Fieldbus Technologies - Industrial Communication & Control - Industrial Electronics & Software - Embedded Systems

User Manual: GCP-MG GCP Modbus gateway

Contents

Important user information

This manual explains how to install, operate and configure a GCP-MG. This device may only be used for the applications described in this document.

This manual is to be used with a GCP-MG with firmware version 1.0 to 1.5.

These instructions are intended for use by trained specialists in electrical installation and control and automation engineering, who are familiar with the applicable national standards and safety procedures.

Safety Precautions

Warning
ELECTRICAL HAZARD
  • This equipment must be installed and serviced only by qualified personnel. Such work should be performed only after reading this entire set of instructions.

  • Before performing visual inspections, tests, or maintenance on this equipment, disconnect all sources of electric power. Assume that all circuits are live until they have been completely de-energized, tested, and tagged. Pay particular attention to the design of the power system. Consider all sources of power, including the possibility of backfeeding.

  • Apply appropriate personal protective equipment and follow safe electrical practices.

  • Turn off all power supplying the equipment in which the GCP-MG is to be installed before installing, wiring or removing the GCP-MG.

  • Always use a properly rated voltage sensing device to confirm that power is off.

  • The successful operation of this equipment depends upon proper handling, installation, and operation. Neglecting fundamental installation requirements may lead to personal injury as well as damage to electrical equipment or other property.

Failure to follow these instructions could result in death or serious injury!

Document conventions

Throughout this manual we use the following symbols and typefaces to make you aware of safety or other important considerations:

Warning

Indicates a potentially hazardous situation that, if not avoided, could result in death or serious injury.

Caution

Indicates a potentially hazardous situation that, if not avoided, could result in damage to equipment.

Important

Indicates information that is critical for successful application and understanding of the product.

Note

Provides other helpful user information that does not fall in above categories.

Tip

Provides supplemental user information.

Acronym

This typeface is used to introduce acronyms or product names.

Command

This typeface is used to represent commands, prompts, input fields and filenames. In the context of programming it is used for functions, variable names, constants or class names.

Placeholder

This typeface is used to represent replacable text. Replaceable text is a placeholder for data you have to provide, like filenames or command line arguments.

User input

This typeface is used to represent data entered by the user or buttons.

Screen output

Screen output or program listing

Introduction

The GCP-MG is a next-generation Modbus/CAN gateway specifically designed to interface Woodward’s GCP-30 Series Genset Controls and LS 4 Circuit Breaker Controls with Modbus networks.

The GCP-MG gateway has been developed in cooperation with Woodward to ensure the highest possible degree of interoperability with Woodward equipment.

The gateway features CAN, serial RS-232 and RS-485 ports as well as an Ethernet port and can be mounted on a DIN rail. On the CAN side it implements the Woodward CAL protocol to connect to the GCP controls. On the serial ports and on Ethernet it implements a Modbus server (Modbus RTU and Modbus/TCP) and accepts connections from Modbus master devices like PLCs and SCADA systems.

Usage and configuration of the gateway is simple and conveniently performed using a web browser which connects to the embedded web server.

GCP-MG

Possible areas of application are:

  • PLC connection

  • Operator panel interfacing

  • HMIs

  • SCADA integration

  • Power station automation

  • Gen set control

  • Remote control & monitoring

  • Data logging

Features

The GCP-MG gateway provides the following key features:

  • Modbus/TCP protocol (Ethernet)

  • Modbus RTU protocol (either RS-232 or RS-485, software configurable)

  • Interfaces with up to 16 GCP-30 controls and up to 8 LS 4 controls

  • Full support of Option SB03 (Cat CCM) and Option SC06 (MTU MDEC)

  • Modbus register layout compatible with GW 4

  • Dedicated Modbus slave ID for each GCP-30 and LS 4 control

  • Large internal buffer for data

  • Complete data set of one GCP-30 unit can be read with a single Modbus transaction

  • Integer/Exponent value pairs for voltages, power and currents are additionally represented as 32-bit floating point registers

  • Transparent handling of data guarantees compatibility with future Woodward firmware updates

  • Serial baud rate up to 115200 bps

  • Support of Modbus function codes 03, 04, 06 and 16

  • Concurrently one Modbus serial line and up to two Modbus/TCP connections

  • Low configuration overhead, just an IP address

  • Embedded web server for easy configuration and commissioning using a web browser

  • Firmware upgradeable via Ethernet

  • Status LEDs for power, Ethernet link, device status and communication status

  • 24 V DC (10-30 V) power supply

  • DIN rail mountable

Quick start checklist

  • Read this set of instructions properly and in its entirety.

  • Mount the unit.

  • Connect the power. Do not connect yet CAN bus or serial ports.

  • Configure the Ethernet communications settings with a web browser (using an Ethernet crossover cable) or with a terminal program like HyperTerminal (using a null modem cable)

  • Configure the CAN bus settings.

  • Configure the serial line communication settings.

  • Configure the operational aspects of the device.

  • Wire CAN bus.

  • Wire serial line interfaces.

Description

The power, CAN and RS-485 terminals are placed on the top side of the unit. The RS-232 and Ethernet connectors are placed on the bottom side of the unit as shown in the following illustration:

GCP-MG connectors
Figure 1. Location of connectors
(1)  Clear front cover (2)  RS-232 Modbus connector (3)  Diagnostic port connector (4)  Ethernet connector (5)  DIN rail clip (6)  Power LED (7)  Ethernet link LED (8)  Device status LED (9)  Modbus/CAN status LED (10)  Power terminals (11)  RS-485 Modbus terminals (12)  CAN connector

LED indicators

Four LEDs located at the front panel indicate the status of the GCP-MG. The LEDs assist maintenance personnel in quickly identifying wiring or communication errors.

A LED test is exercised at power-up, cycling each LED off, green and then red for approximately 0.25 seconds. At the same time the power-on self test of the device is performed.

The following table outlines the indicator condition and the corresponding status after the power-on self-test has been completed:

Table 1. LED diagnostic codes
LED Function Condition Indication

Power

Power

Off

No power applied to the device.

Green

Power supply OK

Link

Ethernet link

Off

No Ethernet link

Green

Ethernet link OK

Status1

Device status

Off

The device has an unrecoverable fault; may need replacing.

Flashing green
1 s rate

Device operational but needs commissioning due to configuration missing, incomplete or incorrect.

Green

The device is operating in normal condition.

Flashing red
1 s rate

Device operational but has a fault listed which requires acknowledgment.

Red

The device has an unrecoverable fault; may need replacing. Flashing sequence and rate of Status2 LED indicates fault class.

Status2

Communication status

Off

CAN connection OK, Connection time-out on Modbus

Green

Both Modbus and CAN connection OK

Flashing red-green
1 s rate

Modbus connection OK, Connection time-out on CAN

Flashing red
1 s rate

Connection time-out on both CAN and Modbus

Red

The device has detected an error that has rendered it incapable of communicating on CAN.

Principles of operation

The GCP-MG establishes a communication channel to each GCP-30 and LS 4 unit connected to the CAN bus. All GCP-30 and LS 4 units transmit multiplexed data values which the GCP-MG stores in its internal data tables. A GCP-30 for example sends a new value every 100 ms, a LS 4 every 200 ms.

The GCP-MG acts as a Modbus server on Ethernet and the serial interface. It accepts connections and Modbus queries from Modbus master devices. The Modbus registers are then served from the GCP-MG's internal data tables. Because of the data table buffering, the Modbus can be polled significantly faster than the update rate on the CAN bus. However faster poll rates would not offer higher update cycles of the data values. The GCP-MG allows a maximum of 2 connections via Modbus/TCP and in addition one serial connection via either RS-485 or RS-232.

Modbus gateway operation
Figure 2. Gateway operation

For remote control, a Modbus master writes control words to a dedicated internal data table which is then cyclically sent to the corresponding GCP-30 or LS 4 unit. One remote control data table is processed every 100 ms. This makes the remote control update cycles depend on the number of units enabled for remote control. For example if 3 GCP-30s are enabled for remote control, it takes 300 ms to send all control words to all GCP-30s, if all 16 GCP-30 and all 8 LS 4 units are enabled for remote control it takes 2.4 seconds ((16 + 8) x 0.1 s) to transmit all control words to the connected units.

Installation

Regulatory notes

icons/warning.png
  1. The GCP-MG is suitable for use in non-hazardous locations only.

  2. The GCP-MG is not authorized for use in life support devices or systems.

  3. Wiring and installation must be in accordance with applicable electrical codes in accordance with the authority having jurisdiction.

  4. This is a Class A device and intended for commercial or industrial use. This equipment may cause radio interference if used in a residential area; in this case it is the operator’s responsibility to take appropriate measures.

  5. The precondition for compliance with EMC limit values is strict adherence to the guidelines specified in this set of instructions. This applies in particular to the area of grounding and shielding of cables.

FCC Notice (USA only)

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.

Industry Canada Notice (Canada only)

This Class A digital apparatus complies with Canadian ICES-003.

Unpacking, handling and storage

icons/important.png
  1. Please read this set of instructions. carefully before fitting it into your system.

  2. Keep all original packaging material for future storage or warranty shipments of the unit.

  3. Do not exceed the specified temperatures.

Before connecting anything

icons/warning.png
  1. Before installing or removing the unit or any connector, ensure that the system power and external supplies have been turned off.

  2. Check the system supply voltage with a multimeter for correct voltage range and polarity.

  3. Connect the power supply cable and switch on the system power. Check if the Power LED is lit.

  4. Turn off system power.

  5. Connect all I/O cables.

  6. Once you are certain that all connections have been made properly, restore the power.

DIN rail mounting and removal

The GCP-MG gateway is designed to be mounted on a 35 mm DIN rail according to DIN/EN 50022. The enclosure features a 35 mm profile at the back which snaps into the DIN rail. No tools are required for mounting. Please observe the rules outlined in [Mounting].

Clip to DIN rail

To mount the unit on a DIN rail, slot the top part of the GCP-MG into the upper guide of the rail and lower the enclosure until the bottom of the red hook clicks into place.

Removal from DIN rail

To remove the GCP-MG from the DIN rail, use a screw driver as a lever by inserting it in the small slot of the red hook and push the red hook downwards. Then remove the unit from the rail by raising the bottom front edge of the enclosure.

Mounting rules

The enclosure provides protection against solid objects according to IP 20 / NEMA Type 1 protection rating. When mounting the unit observe the following rules:

icons/caution.png
  • No water splash and water drops

  • No aggressive gas, steam or liquids

  • Avoid dusty environments.

  • Avoid shock or vibration

  • Do not exceed the specified operational temperatures and humidity range.

  • Mount inside an electrical switchboard or control cabinet.

  • Make sure there is sufficient air ventilation and clearance to other devices mounted next to the unit.

  • Observe applicable local regulations like EN60204 / VDE0113.

Powering the GCP-MG

icons/warning.png

Before connecting power please follow the rules in [Safety] and [Connecting].

Power is supplied via a 3.81 mm 2-pin pluggable terminal block located at the top side of the mounted unit (refer to [DescriptionDiagram]). The following table and picture shows the power terminal socket pinout:

Power supply connector pinout
Power supply pinout
Pin Signal Function

1

V+

Positive voltage supply (10 - 30 V DC)

2

V-

Negative voltage supply, DC power return

Caution Make sure that the polarity of the supply voltage is correct before connecting any device to the serial and CAN ports! A wrong polarity can cause high currents on the ground plane between the V- power supply pin and the CAN port and serial port ground pins, which can cause damage to the device.

Wiring the CAN interface

The CAN interface connects to the GCP-30 and LS 4 devices.

The CAN connector is a male 9-pin D-sub type located at the top side of the mounted unit (refer to [DescriptionDiagram]). It has industry standard CiA DS-102 pinout as shown in the following table and picture:

CAN connector pinout
CAN pinout
Pin Signal Function

1

NC

2

CAN_L

CAN_L bus line

3

CAN_GND

CAN ground

4

NC

5

NC

6

CAN_GND

CAN ground

7

CAN_H

CAN_H bus line

8

NC

9

NC

  • The network must be terminated at both ends with its characteristic impedance, typically a 120 Ohm 1/4 W resistor.

  • Maximum number of electrically connected CAN nodes is 64
    [The number of logically adressable units may be less.]
    .

  • Maximum CAN cable length is 250 m (820 ft) and is derated depending on bit rates and cable type.

  • Stub connections off the main line should be avoided if possible or at least be kept as short as possible. Stub connections must not have terminating resistors.

  • To ensure a high degree of electromagnetic compatibility and surge protection the cable should be twisted pairs and shielded. An additional cable conductor or pair may be used for the CAN_GND reference.

Caution Do not connect the cable shield to the CAN_GND pins or the connector shell! Use an external chassis ground connection to terminate the shield.

The following diagram illustrates a typical interconnection between GCP-30 units and the GCP-MG:

gcpmg_can_wiring.png
Figure 3. CAN bus topology

Wiring the RS-485 Modbus interface

The RS-485 Modbus interface is used for integrating the GCP-MG into a two-wire Modbus over Serial Line network. The use of the RS-485 interface must be configured using the web interface (See [ModbusConfig]). The GCP-MG is a Modbus slave device.

The RS-485 signals are located at the 3.81 mm 6-pin pluggable terminal block on the top side of the mounted unit (refer to [DescriptionDiagram]). The following table and picture shows the pinout:

RS-485 connector pinout
RS-485 pinout
RS-485
 

Pin Signal Function

3

GND

Modbus Common

4

D+

Modbus D1

5

D-

Modbus D0

6

reserved, must be left unconnected

7

reserved, must be left unconnected

8

reserved, must be left unconnected

  • Line termination is required and is typically done with a 120 Ohm 1/4 W resistor. For RS-485 operation the bus must be terminated at both ends.

  • Maximum number of RS-485 nodes without repeater is 32.

  • Stub connections off the main line should be avoided if possible or at least be kept as short as possible. Stub connections must not have terminating resistors.

  • Maximum cable length to 1200 m (4000 ft).

  • To assure a high degree of electromagnetic compatibility and surge protection the cable should be twisted pairs and shielded. An additional cable conductor or pair may be used for the GND reference.

Caution Do not connect the cable shield to the GND pins! Use an external chassis ground connection to terminate the shield.

Wiring the RS-232 Modbus interface

The RS-232 Modbus interface can alternativly be used for serial communication to a Modbus master device instead of RS-485. The use of the RS-232 interface must be configured using the web interface (See [ModbusConfig]). The GCP-MG is a Modbus slave device.

The RS-232 Modbus connector is a male 9-pin D-sub type located at the bottom side of the mounted unit (refer to [DescriptionDiagram]). It has industry standard EIA-574 data terminal equipment (DTE) pinout as shown in the following table and picture:

RS-232 Modbus connector pinout
RS-232 DTE pinout
Pin Signal Function Direction

1

DCD

(unused)

in

2

RXD

Receive data

in

3

TXD

Transmit data

out

4

DTR

(unused)

out

5

GND

Signal ground

6

DSR

(unused)

in

7

RTS

(unused)

out

8

CTS

(unused)

in

9

RI

(unused)

in

  • Maximum cable length is 15 m (50 ft) or a length equal to a line capacitance of 2500 pF, both at the maximum standard bit rate of 20 kbps. If operating at higher bit rates the maximum cable length drops to 3 m (10 ft) at a bit rate of 57.6 kbps.

  • To assure a high degree of electromagnetic compatibility and surge protection the RS-232 cable should shielded. The shield shall be connected to an external chassis ground at the either or both ends, depending on the application.

  • The shield must not be connected to the GND pin.

Note To connect the GCP-MG to a PC (Personal Computer) or any other device with data terminal equipment (DTE) pinout you need a null-modem or cross-over cable.

Connecting Ethernet

The following table describes the 10BASE-T Ethernet RJ-45 connector pinout:

Ethernet connector pinout
RJ-45 pinout
Pin Signal Function

1

TX+

Non-inverting transmit signal

2

TX-

Inverting transmit signal

3

RX+

Non-inverting receive signal

4

Internal termination network

5

Internal termination network

6

RX-

Inverting receive signal

7

Internal termination network

8

Internal termination network

  • We recommend to use Category 5 UTP network cable.

  • Maximum cable length is 100 m (3000 ft).

Connecting to the diagnostic port

The device’s second RS-232 interface is used as a diagnostic port and only active after power-up of the device. It allows configuration of the IP settings and reset of the settings to factory defaults via a terminal program.

The Diagnostic port connector is a male 9-pin D-sub type located at the bottom side of the mounted unit. It has industry standard EIA-574 data terminal equipment (DTE) pinout as shown in the following table and picture:

Diagnostic port connector pinout
RS-232 DTE pinout
Pin Signal Function Direction

1

NC

2

RXD

Receive data

in

3

TXD

Transmit data

out

4

NC

5

GND

Signal ground

6

NC

7

NC

8

NC

9

NC

  • Maximum cable length is 15 m (50 ft) or a length equal to a line capacitance of 2500 pF, both at the maximum standard bit rate of 20 kbps. If operating at higher bit rates the maximum cable length drops to 3 m (10 ft) at a bit rate of 57.6 kbps.

  • To assure a high degree of electromagnetic compatibility and surge protection the RS-232 cable should shielded. The shield shall be connected to an external chassis ground at the either or both ends, depending on the application.

  • The shield must not be connected to the GND pin.

Note To connect the GCP-MG to a PC (Personal Computer) or any other device with data terminal equipment (DTE) pinout you need a null-modem or cross-over cable.

Ethernet & IP configuration

Before configuring the GCP-MG, obtain a unique static IP address, subnet mask, and default gateway address from your network administrator.

The factory default IP address of the GCP-MG is 169.254.0.10 which is in the Automatic Private IP Addressing (APIPA) address range.

There are several methods of configuring the unit’s IP address:

  1. Removing your PC from your corporate network and using a cross-over network cable (see [ConfigCrossOver]).

  2. Via the diagnostic port and a terminal program like HyperTerminal (see [ConfigTerminal]).

  3. Leaving your PC connected to your corporate network and temporarily changing the IP settings on your PC to match the subnet of the GCP-MG (see [ConfigChangeIP]).

Note In order to connect to the GCP-MG via TCP/IP, your PC must be on same IP subnet as the gateway. In most situations this means that the first three numbers of the IP address have to be identical.

IP setup using a web browser and a cross-over network cable

This method applies only to operating systems like Windows, which support APIPA (Automatic Private IP Addressing). It also requires your PC to be configured for DHCP. If your computer is configured with a static IP address, follow the procedure in [ConfigChangeIP].

  1. Disconnect your PC from your corporate network. If your computer is configured for DHCP it should now automatically fall back to use a default IP address from the APIPA range 169.254.x.x (Windows PCs only).

  2. Connect an Ethernet crossover cable from the GCP-MG to the computer.

  3. Start Internet Explorer.

  4. In the address box, type 169.254.0.10 and then press Enter.

  5. Click Configuration… and then Ethernet & IP in the menu on the left side of the page.

  6. Enter the IP address, subnet mask, and gateway address assigned to your GCP-MG, then click Save.

  7. Reconnect your computer to your corporate network.

IP setup using a terminal program like HyperTerminal

  1. Connect a null modem RS-232 cable between your PC and the GCP-MG's diagnostic port.

  2. In Windows XP, click Start, point to All Programs, point to Accessories, point to Communications, and then click HyperTerminal.

  3. When HyperTerminal starts, it opens a dialog box and asks for a name for the new connection. Enter a name (for example, deviceconfig) then click OK.

  4. The Connect to dialog opens. Select the COM port you will be using in the Connect using drop-down list box, then click OK.

  5. Select 9600, 8, None, 1, None in the COM Properties dialog, then click OK.

  6. HyperTerminal is now connected to the serial line.

  7. Keep the space bar pressed in HyperTerminal and power-cycle your device at the same time.

  8. A menu should appear after one or two seconds showing device information, the current IP configuration and a > prompt.

  9. Type SETIP, then press Enter within 10 seconds after the prompt is shown:

    Diagnostic mode
  10. The device will show current values and prompt for new values for IP address, net mask and gateway address. Enter the new values and press Enter. A key press must be received at least every 10 seconds otherwise the device will go back to RUN MODE and resume normal operation.

  11. The gateway will return to the main prompt. Type X and press Enter to leave DIAG MODE and resume normal operation indicated with RUN MODE.

Temporarily changing the IP settings on your PC

This method involves manually assigning an IP address to your PC in the same subnet as the gateway. The default subnet of the gateway is 169.254.0.0/16.

  1. Connect the GCP-MG to your Ethernet network.

  2. On a Windows PC, open the Control Panel and double-click on Network Connections. Right-click on the Network Connection associated with your network adapter and select Properties:

    Windows local area connection context menu

    This will show the Local Area Connection Properties Dialog:

    Local area connection properties dialog

  3. Select the Internet Protocol (TCP/IP) entry and click on Properties to open the TCP/IP Properties dialog as shown below:

    Internet protocol (TCP/IP) properties dialog

  4. Write down your current settings so they can be restored later.

  5. Select Use the following IP address and configure a static IP address in the same subnet as the device, for example 169.254.0.1 and the subnet mask 255.255.0.0. Click OK to save the changes.

  6. Start Internet Explorer.

  7. In the address box, type 169.254.0.10 and then press Enter.

  8. Click Configuration… and then Ethernet & IP in the menu on the left side of the page.

  9. Enter the IP address, subnet mask, and gateway address assigned to your GCP-MG, then click Save.

  10. Restore your computer’s original settings.

Web browser based management

The GCP-MG incorporates an embedded web server. This allows you to connect to the device and monitor and configure it using a web browser. Most browsers should work, provided they support JavaScript. We recommend Internet Explorer 6.0 or higher.

Connecting to the GCP-MG

Once you made sure that your PC is configured to be on the same subnet as the GCP-MG, start your web browser. In the address box, type the IP address of your device (169.254.0.10 is the default), and then press Enter. (See [EthernetConfig])

The web browser will establish communication with the embedded web server and an overview page similar to the following picture will appear:

Web browser access
Figure 4. Device management and configuration via the web browser
(1)  Gateway IP address (2)  Main menu (3)  Configuration sub-menu (4)  Information area

Use the menu bar shown on the left side to navigate the different pages.

Note In order to connect to the GCP-MG via TCP/IP, your PC must be on same IP subnet as the gateway. In most situations this means that the first three numbers of the IP address have to be identical.

Monitoring and diagnostic

The GCP-MG offers several web pages which allow monitoring of the status of the different communication networks and the device performance.

Device status

The Overview page shows the principal device status as shown in the following picture:

Overview screen
Figure 5. Overview page

The value shown in the Device row represents the device status register which keeps track of run-time faults. All run-time faults are latched and must be reset by the user. The following faults can be listed here:

OK

The device is fault free.

Watchdog reset

This warning indicates that the device was reset by it’s internal watchdog supervision circuit.

Brown out reset

This warning indicates that the device was reset by it’s internal supply voltage monitoring circuit. This fault occurs when the supply voltage drops below the lower limit.

Device out of memory

This warning indicates that the internal dynamic memory has been exhausted and due to this a certain function could not be completed.

Device configuration data write failure

This alarm indicates that the configuration data could not be written to the non-volatile memory. Configuration data changes will be lost once the device is power-cycled or reset.

Reset to factory defaults

This alarm indicates that the device' configuration data was reset to factory defaults. The device requires re-commissioning.

The CAN controller status indicates the status of the CAN interface and can be in one of the following states:

ACTIVE

The CAN bus is fault free.

PASSIVE

CAN’s built in fault confinement mechanism has set the node to error passive state due to a large number of errors on the CAN bus. This warning indicates a wiring error.

BUS-OFF

CAN’s built in fault confinement mechanism has set the node to bus-off state due to excessive errors on the CAN bus. This alarm indicates a wiring error. The GCP-MG will not transmit or receive any message on the CAN bus once entered this state. The device needs to be manually restarted on order to recover from this fault.

Modbus connection status

The Modbus Status page shows status and statistics about the Modbus traffic. These values provide valuable information used to troubleshoot Modbus network problems. This page is automatically updated every 5 seconds.

Modbus status screen
Figure 6. Modbus status page
Note This page shows accumulated readings since the GCP-MG was last activated or reset. If power to the GCP-MG is lost, all cumulative values are reset to zero.

The following statistics are maintained:

TCP status

Status of the TCP/IP connection as per TCP finite state machine (refer to RFC 793). If no client is connected the status indicates LISTEN. If a client is connected, it’s IP address is shown.

Accumulative connections

A counter that increments each time a client opens a Modbus/TCP connection.

Requests

A counter that increments each time an inbound request message is successfully received.

Replies

A counter that is incremented each time a reply message is sent back to the master. This includes exception replies.

CRC errors

A counter that increments each time a message is received that has a CRC that does not match what is calculated. Typically the result of wiring issues. Messages with CRC errors are discarded and not replied to.

Invalid frames

A counter that increments each time a malformed Modbus frame is detected. Malformed frames are for example messages larger than the allowed maximum PDU size defined in the Modbus standards. This can be caused by non-Modbus traffic on the network.

Rx time-outs (Modbus serial line)

A counter that increments each time an inter-character time-out occurred during the reception of an inbound message.

Rx time-outs (Modbus/TCP)

A counter that increments if the master connection has timed out. Subsequently the connection is terminated by the GCP-MG. A time-out occurs if no Modbus request is received from a connected client within a 10 second period.

Tx time-outs

Number time-outs occurred when attempting to send a reply message.

The cumulative diagnostic data is reset when the device is power cycled or reset. The data is also reset by pressing the Clear Counter button.

CAN communication status

The CAN Status page shows status and statistics about the CAN bus traffic. These values provide valuable information used to troubleshoot CAN problems. This page is automatically updated every 5 seconds.

CAN communication status screen
Figure 7. CAN communication status page
Note This page shows accumulated readings since the GCP-MG was last activated or reset. If power to the GCP-MG is lost, all cumulative values are reset to zero.

The CAN communication channel between a GCP-30 or LS 4 unit and the GCP-MG can be in one of the following states:

OK

The CAN communication channel with the GCP-30 or LS 4 unit has been established. The GCP-30 or LS 4 control is cyclically updating data.

WAIT

The presence of a GCP-30 or LS 4 unit has been detected however the GCP-MG is currently waiting to receive a complete data set. It takes approximately between 2.3 and 3 seconds to receive a full data set from the GCP-30 and approximately 10 seconds from the LS 4.

TIME-OUT

No CAN message was received for a period of 1 second. A GCP-30 control is supposed to send a CAN message every 100 ms, a LS 4 every 200 ms.

The following statistics are maintained:

Messages received

A counter that increments each time an inbound CAN message matching the shown CAN ID is successfully received.

Messages sent

A counter that is incremented each time a CAN message is sent. CAN messages are only sent if Remote Control is enabled for this GCP-30 or LS 4.

The cumulative diagnostic data is reset when the device is power cycled or reset. The data is also reset by pressing the Clear Counter button.

Finding the firmware version and serial number

Click on the About menu entry on the menu bar to show the product information as shown below:

About Screen
Figure 8. About page

This product information is important for service and support inquiries. The following product information is provided:

Product name

The name of the product.

Hardware version

GCP-MG hardware version.

Firmware version

The firmware version that is installed on the GCP-MG.

Serial number

The serial number of the GCP-MG. The serial number is specific to your device.

Configuring and commissioning

The configuration pages are accessed by clicking on the Configuration… menu entry on the menu bar which then expands a configuration sub-menu. All configuration settings are kept in the device' non-volatile memory.

Note If you make changes to any settings, remember to save each page before changing to a different page!

Configuring Ethernet and IP

Select the Configuration→Ethernet & IP sub-menu from the menu bar to open the Ethernet and IP settings which are shown below:

Ethernet and IP settings screen
Figure 9. Ethernet and IP settings page

The following Ethernet parameters are shown:

MAC address

The device' unique MAC address. This number is hard coded and cannot be changed.

The following Internet protocol (IP) settings can be entered:

IP address

The IP address assigned to this device.

Subnet mask (also known as network mask)

If you have a router, enter the subnet mask for the segment to which this device is attached.

Gateway address

If your network segment has a router, enter its IP address here. Otherwise leave the address as 0.0.0.0.

Once you click Save the new settings are stored and applied instantly. The new settings are confirmed with the following page:

IP settings changed confirmation screen
Figure 10. IP settings changed confirmation
Important Please write down the new IP address so you are able to communicate with the device in the future!

Configuring GCP-30 and LS 4 Modbus access

Access from the Modbus to a GCP-30 and LS 4 unit can be configured on a per unit basis. You have the option of completely disabling a gen set control for Modbus access, have read-only access or enabling remote control either unsupervised or time-out supervised.

To configure the Modbus access, enter the Configuration sub-menu and click on either the GCP-30 or LS 4 menu entry. This opens either the GCP-30 settings or the LS 4 settings as shown below:

GCP-30 Modbus settings screen
Figure 11. GCP-30 settings page

The CAN identifiers and Modbus slave identifiers are preassigned and cannot be changed. The following Modbus access options can be selected:

disabled

Modbus access to this unit is completely disabled. The gateway does not respond to a Modbus master query and ignores messages for the associated Modbus slave ID. The associated slave ID can be used by another Modbus device connected to the Modbus network.

read-only

Modbus access is enabled for read-only data. No remote control is possible, access to the remote control data table 4:0001 will result in Modbus exception code 03 Illegal Value being returned.

control

Modbus access is enabled for reading and for remote control. No supervision of Modbus master activity takes place (See Monitored Control). Before being able to use Remote Control, please check that the GCP-30 unit has been parameterized accordingly, otherwise the messages sent by the GCP-MG are ignored by the GCP-30. Refer to chapter Interface in your GCP-30 Series Genset Control manual. For Remote Control to work, GCP-30 parameter 120 Control via COM X1X5 must be turned on and discrete input Automatic 2 (Terminal 5) must be asserted. If remote alarm acknowledgment is required, GCP-30 parameter 122 Ackn. F2,F3 via COM interf must be turned on in addition. If power setpoint shall be accepted by the GCP-30, discrete input Automatic 1 (Terminal 3) must be de-energized and parameter 78 Power set point value: external input must be set to OFF.

monitored control

Similar to control but in addition the remote control is monitored and a Modbus muster must cyclically update the remote control words by writing to the remote control data table. If a Modbus master fails to do this within a certain time limit, the GCP-MG will trigger an Interface error X1X5 alarm on the GCP-30. For Monitored Control to be effective, GCP-30 Parameter 121 Supervision X1X5 must be turned on.

Once you click Save the new settings are stored and applied instantly. A confirmation message is shown.

Important It is of great importance to ensure that there is not two devices with the same Modbus address. In such a case, an abnormal behavior of the whole serial bus can occur, the master being then in the impossibility to communicate with all present slaves on the bus.

Configuring serial line Modbus

The Modbus settings for serial line can be configured to match the network configuration of your Modbus master device. Select the Configuration→Modbus sub-menu from the menu bar to open the Modbus settings which are shown below:

Modbus settings screen
Figure 12. Modbus settings page

The following Modbus settings can be entered:

Physical layer

Can be set to two-wire RS-485 or RS-232 mode. RS-485 is the default. Depending on this setting either the D-sub (RS-232) connector or the terminal block connector (RS-485) of the GCP-MG is utilized.

Transmission mode

Only RTU mode can be selected here.

Baud rate

9600 and 19200 are the most common baud rates for Modbus. 19200 is the default setting.

Data bits

Only 8 data bits can be selected here which is a requirement for RTU.

Stop bits

Can be configured to be 1 or 2. The Modbus standard mandates that 2 stop bits are configured when using no parity.

Parity

Changes parity mode to either none, even or odd. The default parity mode for Modbus is even parity.

Once you click Save the new settings are stored and applied instantly. A confirmation message is shown.

Remote restarting the device

You can perform a remote restart of the device from the web interface. A remote restart is similar to power cycling the device. Possibly connected clients are disconnected and communication is interrupted until the device has rebooted.

To perform a remote restart, click on the Configuration sub-menu and then click on the Restart menu entry. This will open the device restart page as shown below:

Restart device screen
Figure 13. Restart device page

Click on the Restart button to perform a restart of the device. The restart is confirmed with the following notification:

Restart confirmation screen
Figure 14. Restart confirmation page

Please allow a few seconds before continuing working with the device as it has to fully start-up first, before being able to respond to further web browser requests.

Note After a remote restart a Watchdog reset alarm is shown on the device' home page. This is a side-effect of the remote restart procedure and the alarm shall be ignored and cleared.

Modbus data reference

This chapter describes how GCP-30 and LS 4 data values are organized in logical blocks and accessed via Modbus.

The GCP-MG supports the Modbus function codes 03, 04, 06 and 16. A maximum of 100 16-bit words can be requested with Modbus command 04. This makes it possible to read the complete data set of a GCP-30 or LS 4 unit with a single Modbus transaction.

Table 2. Supported Modbus function codes
Modbus function code Function name Access Max. number of 16-bit words per transaction Data table/block

04

Read input registers

read

100

3:0000

03

Read holding registers

write

3

4:0000

06

Write single register

write

1

4:0000

16

Write multiple registers

write

3

4:0000

The GCP-MG emulates a virtual Modbus slave device for each GCP-30 and LS 4 unit connected to the CAN bus. This simplifies management of PLC and SCADA variable tag tables, as the Modbus start address is identical for all GCP-30 and LS 4 units.

The following tables show the relation of an individual unit with the Modbus slave ID and the Modbus register range:

Table 3. Modbus slave ID relationship
Unit Modbus slave ID Modbus read address range Modbus write address range Modbus floating point address range CAN ID

GCP-30 #1

1

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

801

GCP-30 #2

2

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

802

GCP-30 #3

3

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

803

GCP-30 #4

4

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

804

GCP-30 #5

5

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

805

GCP-30 #6

6

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

806

GCP-30 #7

7

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

807

GCP-30 #8

8

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

808

GCP-30 #9

9

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

809

GCP-30 #10

10

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

810

GCP-30 #11

11

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

811

GCP-30 #12

12

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

812

GCP-30 #13

13

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

813

GCP-30 #14

14

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

814

GCP-30 #15

15

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

815

GCP-30 #16

16

3:0001-3:0100

4:0001-4:0003

3:1001-3:1076

816

LS 4 #1

17

3:0001-3:0100

4:0003

3:1001-3:1034

817

LS 4 #2

18

3:0001-3:0100

4:0003

3:1001-3:1034

818

LS 4 #3

19

3:0001-3:0100

4:0003

3:1001-3:1034

819

LS 4 #4

20

3:0001-3:0100

4:0003

3:1001-3:1034

820

LS 4 #5

21

3:0001-3:0100

4:0003

3:1001-3:1034

821

LS 4 #6

22

3:0001-3:0100

4:0003

3:1001-3:1034

822

LS 4 #7

23

3:0001-3:0100

4:0003

3:1001-3:1034

823

LS 4 #8

24

3:0001-3:0100

4:0003

3:1001-3:1034

824

A standard LS 4 occupies only the range from 3:0001 to 3:0029. The remaining range is reserved for future expansion of the LS 4 or custom versions.

Note If no response was obtained from the target GCP-30 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

The following table lists the Modbus exception responses sent by the gateway instead of a normal response message in case of an error:

Table 4. Modbus exception codes
Modbus exception code Exception name Reason

01

Illegal function

A Modbus master sent a Modbus function which is not supported by the gateway. Please refer to the documentation of the individual data tables for valid function codes.

02

Illegal data address

A Modbus master queried a non-existing Modbus address or the queried range points outside of a data table. Please refer to the documentation of the individual data tables for valid address ranges.

03

Illegal value

A Modbus master sent a Modbus message which’s structure or implied length is invalid. Also returned if a Modbus master tries to access remote control functions for a unit configured as read-only.

0B

Gateway target device failed to respond

A Modbus master tries to access data which is unavailable because no response was obtained from the target GCP-30 or LS 4 unit. Usually means that the unit is not present on the CAN bus.

Alternative access of Input Registers as Holding Registers

Since firmware version 1.3 the Input registers located in the 3:0001 and 3:1001 range can alternatively be accessed as Holding registers in the range 4:0101 and 4:1001 respectively.

GCP-30 MUX data table 3:0001

The GCP-30 MUX data table contains all data values a GCP-30 is transmitting cyclically on the CAN bus. A GCP-30 sends a value every 100 ms. Therefore it takes approximately between 2.3 and 3 seconds for a complete update of the data table with new values from the CAN bus. The data table can be polled much faster by a Modbus master, however faster poll rates would not offer higher update cycles.

The GCP-30 MUX data table is located in the so called Input register address block, which sometimes is also identified with offset 3:0000.
[Alternative access as "Holding Registers" is possible at 4:0101 since firmware 1.3]
The block is accessed using Modbus function code 04 Read input registers.

Only Modbus address 0001 can be accessed at all times. All other Modbus addresses can only be accessed if the CAN communication between GCP-MG and GCP-30 has been established. If this is not the case, Modbus exception code 0B Gateway target device failed to respond is returned indicating the GCP-30 is not present on the CAN bus.

For the GCP-30 MUX data table, the GCP-MG acts as a transparent gateway between the GCP-30 unit and the Modbus. Except for the device status register at Modbus address 0001, it does not perform any modification to the representation of the data values.

The Woodward "GCP-30 Series Genset Control" manual [GCP30] is the ultimate reference for the encoding and representation of the data values. Please refer to the "Transmission Telegram" table in Appendix C "Interface Control" of this manual for further details.

The following table shows the relationship between Modbus addresses and the so called MUX identifiers or word numbers:

Table 5. Modbus addresses for GCP-30 MUX values
Block Modbus address GCP-30 MUX GCP-30 word no. GCP-30 manual designator

3

0001

n/a

n/a

CAN device status register
Bit 1: 1 = CAN communication GCP-MG and GCP-30 OK
Bit 2-16: reserved for future use

3

0002

0/1

1

Generator voltage delta V12

3

0003

0/2

2

Generator frequency f

3

0004

0/3

3

Actual generator real power P

3

0005

1/1

4

Exponents

3

0006

1/2

5

Real power set point value

3

0007

1/3

6

Conversion factor steps to kW

3

0008

2/1

7

Bus bar voltage delta V12

3

0009

2/2

8

Mains voltage delta V12

3

0010

2/3

9

Currently present alarm class

3

0011

3/1

10

Control register 2

3

0012

3/2

11

Actual mains interchange (import/export) real power

3

0013

3/3

12

Control register 1

3

0014

4/1

13

Alarm message IKD (SC06)

3

0015

4/2

14

Internal alarm 6

3

0016

4/3

15

Generator voltage delta V23

3

0017

5/1

16

Generator voltage delta V31

3

0018

5/2

17

Generator voltage delta V1N

3

0019

5/3

18

Generator voltage delta V2N

3

0020

6/1

19

Generator voltage delta V3N

3

0021

6/2

20

Configuration [T1]-[T4]

3

0022

6/3

21

Engine speed measured via the Pickup

3

0023

7/1

22

Generator current in L1

3

0024

7/2

23

Generator current in L2

3

0025

7/3

24

Generator current in L3

3

0026

8/1

25

Actual generator reactive power

3

0027

8/2

26

Generator cos phi

3

0028

8/3

27

Current reserve power in the system in kW

3

0029

9/1

28

Current actual real power in the system

3

0030

9/2

29

Number of participants on the CAN bus

3

0031

9/3

30

High byte: Mains status, Low byte: Generator status

3

0032

10/1

31

Exponents

3

0033

10/2

32

Bus bar frequency

3

0034

10/3

33

Configuration [T5]-[T8]

3

0035

11/1

34

Mains voltage delta V23

3

0036

11/2

35

Mains voltage delta V31

3

0037

11/3

36

Mains voltage delta V1N

3

0038

12/1

37

Mains voltage delta V2N

3

0039

12/2

38

Mains voltage delta V3N

3

0040

12/3

39

Mains frequency out off VN12/VN23/VN31

3

0041

13/1

40

Mains current in L1

3

0042

13/2

41

Mains reactive power

3

0043

13/3

42

Mains power factor

3

0044

14/1

43

Exponents

3

0045

14/2

44

Exponents

3

0046

14/3

45

Engine operating hours, high word

3

0047

15/1

46

Engine operating hours, low word

3

0048

15/2

47

Hours until next maintenance

3

0049

15/3

48

Engine start number

3

0050

16/1

49

Operation mode

3

0051

16/2

50

Generator active energy, high word

3

0052

16/3

51

Generator active energy, low word

3

0053

17/1

52

Battery voltage

3

0054

17/2

53

Internal alarm 1

3

0055

17/3

54

Internal alarm 2

3

0056

18/1

55

Internal alarm 3

3

0057

18/2

56

Internal alarm 4

3

0058

18/3

57

Internal alarm 5

3

0059

19/1

58

External alarm 1

3

0060

19/2

59

External alarm 2

3

0061

19/3

60

Internal alarm 7

3

0062

20/1

61

Analogue input T1

3

0063

20/2

62

Analogue input T2

3

0064

20/3

63

Analogue input T3

3

0065

21/1

64

Analogue input T4

3

0066

21/2

65

Analogue input T5

3

0067

21/3

66

Analogue input T6

3

0068

22/1

67

Analogue input T7

3

0069

22/2

68

Alarm messages IKD2 (SC06)

3

0070

22/3

69

LCD-display / Pickup

3

0071 - 0100

Not used by a standard GCP-30, reserved for options, future expansion or custom versions. See below for allocation by option SB03 and SC06.

Note If no response was obtained from the target GCP-30 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

Allocation with options SB03 and SC06

Table 6. Modbus addresses for SB03 Cat CCM and SC06 MTU MDEC options
Block Modbus address GCP-30 MUX GCP-30 word no. SB03 option Cat CCM designator SC06 option MTU MDEC designator

3

0071

23/1

70

Coolant temperature

Woodward ST-3 control lambda setpoint

3

0072

23/2

71

Oil pressure

Woodward ST-3 control lambda reading

3

0073

23/3

72

Raw water temperature

Woodward ST-3 control actuator position

3

0074

24/1

73

Turbo charger intake temperature

Engine speed

3

0075

24/2

74

Oil temperature

Oil pressure

3

0076

24/3

75

Intake manifold temperature

Alarm code

3

0077

25/1

76

Throttle position

Operating hours

3

0078

25/2

77

Engine speed

Coolant temperature

3

0079

25/3

78

Multiplexed ECU alarms 1

Oil temperature

3

0080

26/1

79

Multiplexed ECU alarms 2

Fuel temperature

3

0081

26/2

80

Multiplexed ECU alarms 3

Speed reply

3

0082

26/3

81

Multiplexed ECU alarms 4

Multiplexed ECU alarm group 1

3

0083

27/1

82

Multiplexed ECU alarm group 2

3

0084

27/2

83

Reserved MDEC bit 11

3

0085

27/3

84

Reserved MDEC bit 12

3

0086

28/1

85

Reserved MDEC bit 13

3

0087

28/2

86

Reserved MDEC bit 14

3

0088

28/3

87

Reserved MDEC bit 15

3

0089

29/1

88

Reserved MDEC bit 16

3

0090

29/2

89

Reserved MDEC bit 17

3

0091

29/3

90

Reserved MDEC bit 18

GCP-30 floating point table 3:1001

The GCP-30 floating point data table is located in the so called Input register address block, which is sometimes also identified with offset 3:0000.
[Alternative access as Holding Registers is possible at 4:1001 since firmware 1.3]
This block is accessed using Modbus function code 04 Read input registers.

The floating point values are encoded in industry standard single-precision (32-bit) IEEE 754 format. The 32-bit floating point values are transmitted as pairs of two consecutive 16-bit registers in little-endian word order.

Table 7. Modbus addresses for GCP-30 floating point data table
Block Modbus address GCP-30 MUX GCP-30 word no. GCP-30 manual designator Unit

3

1001

0/1

1

Generator voltage delta V12

V

3

1003

0/2

2

Generator frequency f

Hz

3

1005

0/3

3

Actual generator real power P

kW

3

1007

1/2

5

Real power set point value

kW

3

1009

2/1

7

Busbar voltage delta V12

V

3

1011

2/2

8

Mains voltage delta V12

V

3

1013

3/2

11

Actual mains interchange (import/export) real power

kW

3

1015

4/3

15

Generator voltage delta V23

V

3

1017

5/1

16

Generator voltage delta V31

V

3

1019

5/2

17

Generator voltage delta V1N

V

3

1021

5/3

18

Generator voltage delta V2N

V

3

1023

6/1

19

Generator voltage delta V3N

V

3

1025

6/3

21

Engine speed measured via the pickup

rpm

3

1027

7/1

22

Generator current in L1

A

3

1029

7/2

23

Generator current in L2

A

3

1031

7/3

24

Generator current in L3

A

3

1033

8/1

25

Actual generator reactive power

kW

3

1035

8/2

26

Generator cos phi

3

1037

8/3

27

Current reserve power in the system in kW

kW

3

1039

9/1

28

Current actual real power in the system

kW

3

1041

10/2

32

Busbar frequency

Hz

3

1043

11/1

34

Mains voltage delta V23

V

3

1045

11/2

35

Mains voltage delta V31

V

3

1047

11/3

36

Mains voltage delta V1N

V

3

1049

12/1

37

Mains voltage delta V2N

V

3

1051

12/2

38

Mains voltage delta V3N

V

3

1053

12/3

39

Mains frequency out off VN12/VN23/VN31

V

3

1055

13/1

40

Mains current in L1

A

3

1057

13/2

41

Mains reactive power

kVAR

3

1059

13/3

42

Mains power factor

3

1061

17/1

52

Battery voltage

V

3

1063

20/1

61

Analogue input T1

3

1065

20/2

62

Analogue input T2

3

1067

20/3

63

Analogue input T3

3

1069

21/1

64

Analogue input T4

3

1071

21/2

65

Analogue input T5

3

1073

21/3

66

Analogue input T6

3

1075

22/1

67

Analogue input T7

GCP-30 remote control data table 4:0001

The GCP-30 remote control data table is located in the so called Holding Register address block, which sometimes is also identified with offset 4:0000. This block can be written to using Modbus function code 16 Write multiple registers or function code 06 Write single register.

If remote control is enabled, the three remote control words are sent cyclically to the respective GCP-30. They are also stored in the GCP-MG's memory and can be read back using Modbus function code 03 Read holding registers.

Note Remote control is disabled by default and Modbus exception code 03 Illegal value is returned if a Modbus master tries to access remote control functions for a unit configured as read-only. Remote control can be enabled on a per unit basis through the GCP-30 settings page of the GCP-MG (see [ConfigModbusAccess]).
Table 8. Modbus addresses for GCP-30 remote control
Block Modbus address GCP-30 word no. GCP-30 manual designator Encoding

4

0001

501

Generator real power set-point

kW with control argument

4

0002

502

Generator power factor set-point

cos phi x 100

4

0003

503

Control word

Bit 1: 1 = Remote start
Bit 2: 1 = remote stop (high priority)
Bit 3: write always 0
Bit 4: write always 0
Bit 5: 1 = Alarm acknowledgment
Bit 6-16: internal use

Note If no response was obtained from the target GCP-30 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

LS 4 MUX data table 3:0001

The LS 4 MUX data table contains all data values a LS 4 is transmitting cyclically on the CAN bus. A LS 4 sends a value every 200 ms. Therefore it takes approximately 10 seconds for a complete update of the data table with new values from the CAN bus. The data table can be polled much faster by a Modbus master, however faster poll rates would not offer higher update cycles.

The LS 4 MUX data table is located in the so called Input register address block, which sometimes is also identified with offset 3:0000.
[Alternative access as Holding Registers is possible at 4:0101 since firmware 1.3]
The block is accessed using Modbus function code 04 Read input registers.

Only Modbus address 0001 can be accessed at all times. All other Modbus addresses can only be accessed if the CAN communication between GCP-MG and LS 4 has been established. If this is not the case, a Modbus exception code 0B Gateway target device failed to respond is returned, indicating the LS 4 unit is not present on the CAN bus.

For the LS 4 MUX data table, the GCP-MG acts as a transparent gateway between the LS 4 unit and the Modbus. Except for the device status register at Modbus address 0001, it does not perform any modification to the representation of the data values.

The Woodward "LS 4 Circuit Breaker Controls" manual [LS4] is the ultimate reference for the encoding and representation of the data values. Please refer to the "Transmission telegram" table in Appendix E "Interface" of this manual for further details.

The following table shows the relationship between Modbus addresses and the so called MUX identifiers or word numbers.

Table 9. Modbus addresses for LS 4 MUX values
Block Modbus address LS 4 MUX LS 4 word no. LS 4 manual designator

3

0001

n/a

n/a

CAN device status register
Bit 1: 1 = CAN communication between GCP-MG and LS 4 OK
Bit 2-16: reserved for future use

3

0002

0/1

1

Protocol number 1600

3

0003

0/2

2

Voltage L12 system A

3

0004

0/3

3

Voltage L23 system A

3

0005

1/1

4

Voltage L31 system A

3

0006

1/2

5

Voltage L1N system A

3

0007

1/3

6

Voltage L2N system A

3

0008

2/1

7

Voltage L3N system A

3

0009

2/2

8

Frequency system A

3

0010

2/3

9

Current L1 system A

3

0011

3/1

10

Current L2 system A

3

0012

3/2

11

Current L3 system A

3

0013

3/3

12

Power factor

3

0014

4/1

13

Real power system A

3

0015

4/2

14

Reactive power system A

3

0016

4/3

15

Voltage L12 system B

3

0017

5/1

16

Voltage L23 system B

3

0018

5/2

17

Voltage L31 system B

3

0019

5/3

18

Frequency system B

3

0020

6/1

19

Exponent

3

0021

6/2

20

Exponent

3

0022

6/3

21

Internal alarms 1

3

0023

7/1

22

Internal alarms 2

3

0024

7/2

23

Internal alarms 3

3

0025

7/3

24

Internal alarms 4

3

0026

8/1

25

Internal alarms 5

3

0027

8/2

26

Internal alarms 6

3

0028

8/3

27

Internal alarms 7

3

0029

9/1

28

Internal Diagnosis

3

0030 - 0100

Not used by a standard LS 4, reserved for future expansion or custom versions.

Note If no response was obtained from the target LS 4 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

LS 4 floating point data table 3:1001

The LS 4 floating point data table is located in the so called Input register address block, which is sometimes also identified with offset 3:0000.
[Alternative access as Holding Registers is possible at 4:1001 since firmware 1.3]
This block is accessed using Modbus Function Code 04 Read input registers.

The floating point values are encoded in industry standard single-precision (32-bit) IEEE 754 format. The 32-bit floating point values are transmitted as pairs of two consecutive 16-bit registers in little-endian word order.

Table 10. Modbus addresses for LS 4 floating point data table
Block Modbus address LS 4 MUX LS 4 word no. LS 4 manual designator Unit

3

1001

0/2

2

Voltage L12 system A

V

3

1003

0/3

3

Voltage L23 system A

V

3

1005

1/1

4

Voltage L31 system A

V

3

1007

1/2

5

Voltage L1N system A

V

3

1009

1/3

6

Voltage L2N system A

V

3

1011

2/1

7

Voltage L3N system A

V

3

1013

2/2

8

Frequency system A

Hz

3

1015

2/3

9

Current L1 system A

A

3

1017

3/1

10

Current L2 system A

A

3

1019

3/2

11

Current L3 system A

A

3

1021

3/3

12

Power factor

3

1023

4/1

13

Real power system A

kW

3

1025

4/2

14

Reactive power system A

kVAR

3

1027

4/3

15

Voltage L12 system B

V

3

1029

5/1

16

Voltage L23 system B

V

3

1031

5/2

17

Voltage L31 system B

V

3

1033

5/3

18

Frequency system B

Hz

Note If no response was obtained from the target LS 4 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

LS 4 remote control data table 4:0001

The LS 4 remote control data table is located in the so called Holding Register address block, which sometimes is also identified with offset 4:0000. The block can be written to using Modbus function code 16 Write multiple registers or function code 06 Write single register.

If Remote Control is enabled, the three remote control words are sent cyclically to the respective LS 4. They are also stored in the GCP-MG's memory and can be read back using Modbus function code 03 Read holding registers.

Note Remote control is disabled by default and Modbus exception code 03 Illegal value is returned if a Modbus master tries to access remote control functions for a unit configured as read-only

Remote control can be enabled on a per unit basis through the LS 4 settings page of the GCP-MG (see [ConfigModbusAccess]).

Table 11. Modbus addresses for LS 4 remote control
Block Modbus address LS 4 word no. LS 4 manual designator Encoding

4

0001

501

(not used for LS 4)

4

0002

502

(not used for LS 4)

4

0003

503

Control word

Bit 1: 1 = Open CB (high priority)
Bit 2: 1 = Close CB
Bit 3: write always 0
Bit 4: write always 0
Bit 5: 1 = Alarm Acknowledgment
Bit 6-16: internal use

Note If no response was obtained from the target LS 4 unit, Modbus exception code 0B Gateway target device failed to respond is returned.

Decommissioning

Before disconnecting the GCP-MG unit please follow the rules in [Safety].

Disconnecting

icons/warning.png
  1. Ensure that the system power and external supplies have been turned off.

  2. Disconnect power supply plug.

  3. Disconnect all I/O cables.

  4. Remove the GCP-MG from the DIN rail following the procedure described in [removal].

Disposal

icons/AJ_Recycling_Symbol.png

This product must be disposed of at a specialized electronic waste recycling facility. Do not dispose of in domestic waste.

Appendix A: Specifications

Product name

GCP-MG

Interfaces

Ethernet

1

Serial ports

1 for Modbus (either RS-232 or RS-485, software configurable)
1 for diagnostics (RS-232)

CAN

1

User interface

LED indicators

Power (green), Ethernet link (green), 2 status (bi-color red/green)

Monitoring & configuration

Web browser based

Diagnostic

High availability features

Watchdog supervision, brown-out detection

CAN interface

Connector

male 9-pin D-sub, CiA DS-102 pin-out

Physical layer

ISO 11898

Isolation

non-isolated

Speed

125 kBit/s

Max. number of connected nodes

64

Protocols

CAL 2.0

RS-485 Modbus interface

Connector

3.81 mm 6-pin pluggable terminal block header

Physical layer

EIA-485-A, 2-wire

Isolation

non-isolated

Speed

300, 600, 1200, 2400, 4800, 9600, 19200, 57600, 115200 bps

Max. number of nodes

32

Protocols

Modbus RTU slave

RS-232 Modbus interface

Connector

male 9-pin D-sub, DTE, EIA-574 pin-out

Physical layer

EIA-232-F

Isolation

non-isolated

Signals

RXD, TXD, RTS, CTS, DTR, DSR, DCD, RI

Speed

300, 600, 1200, 2400, 4800, 9600, 19200, 57600, 115200 bps

Protocols

Modbus RTU slave

RS-232 diagnostic port

Connector

male 9-pin D-sub, DTE, EIA-574 pin-out

Physical layer

EIA-232-F

Isolation

n/a

Signals

RXD, TXD

Speed

9600 bps

Protocols

ASCII terminal

Ethernet port

Connector

8-pin RJ-45 socket for Cat 5 UTP

Physical & Data Link Layer Layer

IEEE 802.3i 10BASE-T

Isolation

1.5 kV galvanic

Speed

10 Mbit/s

Max. cable length

100 m (328 ft)

Ethernet frame types

802.3

Protocols

Modbus/TCP slave, HTTP, IP, TCP, ARP

Concurrent connections

2 Modbus/TCP, 2 HTTP

Power supply

Connector

3.81 mm 2-pin pluggable terminal block header

Voltage

10-30 V DC

Current

30 mA typical @ 24 V DC

Intrinsic consumption

750 mW

Electromagnetic compatibility

Emissions (radiated and conducted)

AS/NZS CISPR 22 / EN 55022 (Class A)

Immunity

EN 55024

Electrostatic discharge

EN 61000-4-2

Radiated RF

EN 61000-4-3

Fast transients

EN 61000-4-4

Conducted RF

EN 61000-4-6

Enclosure

Material

Self-extinguishing PC/ABS blend (UL 94-V0)

Mounting

35 mm DIN rail (EN 60715)

Classification / Type rating

IP 20 / NEMA Type 1

Cooling

Convection

Environmental

Operating temperature

0 to 60 °C / 32 to 140 °F

Storage temperature

-25 to 85 °C / -13 to 185 °F

Humidity

10 to 95% non condensing

Operating ambience

Free from corrosive gas, minimal dust

Physical

Dimensions

101 x 22.5 x 120 mm / 3.98 x 0.886 x 4.72 in

Weight

0.13 kg / 0.287 lb

Compliance

Australia

C-Tick

Europe

CE, RoHS

USA

FCC Part 15 (Class A)

Canada

ICES-003 (Class A)

Dimensions

Dimension Drawing
Figure 15. Enclosure dimensions

References

  • [GCP30] Woodward Governor Company, "GCP-30 Series Packages Genset Control — Configuration", Manual 37365A, February 2007

  • [LS4] Woodward Governor Company, "LS 4 Circuit Breaker Control — Manual", Manual 37105A, May 2004

Glossary

10BASE-T

10 Mbit/s twisted pair Ethernet standard. Standardized in IEEE 802.3i

APIPA

Automatic Private IP Addressing

CAN

Controller area network. Standardized in ISO 11898.

CiA DS-102

Standard for the pinout of CAN connectors

Class A

Class A equipment is that used in commercial or light industrial environments.

DCE

Data communications equipment. DTE and DCE devices have different pinouts for RS-232 connectors. A Modem for example is a DCE.

DIN rail

35 mm wide mounting bracket standardized in DIN/EN 50022.

DTE

Data terminal equipment. DTE and DCE devices have different pinouts for RS-232 connectors. A PC for example is a DTE.

EIA-232

Standard for serial transmission of data between two devices, also known as RS-232 and V.24.

EIA-422

ANSI/TIA/EIA-422 standard for serial transmission of data between two devices, also known as RS-422 and V.11.

EIA-485

ANSI/TIA/EIA-485 standard for serial transmission of data between multiple devices, also known as RS-485.

EIA-574

Standard for the pinout of serial D-sub connectors.

EMC

Electromagnetic compatibility

EMI

Electromagnetic interference

ESD

Electrostatic discharge. ESD can damage electronic equipment.

IEEE

Institute of Electrical and Electronics Engineers

IP

Ingress Protection Rating standardized in IEC 60529. Standard for various grades of electrical enclosures.

ISO

International Standards Organisation

MAC address

Every piece of Ethernet hardware has a unique number assigned to it called it’s MAC address. MAC addresses are administered and assigned by the IEEE organization.

Modbus

Fieldbus protocol used in the process automation industry. It uses a master and slave structure. Originally developed by Modicon, now part of Schneider Automation.

NEMA

National Electrical Manufacturers Association. NEMA defines standards for various grades of electrical enclosures.

Node

A communications device on the network

PC/ABS

Polycarbonate-ABS. Widely used thermoplastic material.

PLC

Programmable Logic Controller

RS-232

See EIA-232.

RS-422

See EIA-422.

RS-485

See EIA-485.

UL 94

Plastics flammability standard released by Underwriters Laboratories of the USA.


Document revision history

2007-05-14, 1.0

Initial Release for hardware version J367-S3-PB and firmware version 1.0

2008-07-28, 1.1

LED description added. Added max. number of Modbus/TCP connections. Corrected weight. Updated company name and address. Editorial Changes.

2010-10-32, 1.2

Added alternative holding register address range. Editorial Changes.

2011-04-06, 1.3

Editorial Changes.


No part of this material may be reproduced or transmitted in any form or by any means or used to make any derivative work without express written consent from the copyright holders.

proconX is a trademark of proconX Pty Ltd. Modbus is a registered trademark of Schneider Automation Inc. All other product and brand names mentioned in this document may be trademarks or registered trademarks of their respective owners.

Disclaimer

proconX Pty Ltd makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty which is detailed in the Terms and Conditions located on the Company’s Website. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of proconX are granted by the Company in connection with the sale of proconX products, expressly or by implication. proconX products are not authorized for use as critical components in life support devices or systems.

Support & product feedback

We provide an electronic support and feedback system for our proconX products. It can be accessed through the following web link:

Your feedback and comments are always welcome. It helps improving this product.

Contact

For further information about the GCP-MG product or this document please contact us at:

proconX Pty Ltd
Unit 7 / 14 Argon St
Sumner QLD 4074
Australia
Tel +61-7-3376 3911
Website: http://www.proconx.com/gcpmg

Terms of Use | Terms of Sale | Privacy Policy | Info & Contact     © 2005-2017 proconX Pty Ltd