Video: How to configure an ION meter as a Modbus Gateway

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Issue
PM8000, ION7550, ION7650, and ION8650 devices equipped with Ethernet communication can be used as Ethernet Gateways to allow communications to serial devices. The Ethergate feature of the meters requires that TCP Ports 7801, 7802 or 7803 be used to access the gateway connection. 3rd Party Software or Hardware may not be able to communicate Modbus on a port other than the standard 502, and therefore are unable to access the downstream meters.

Product Line
PM8000
ION 7550 / 7650
ION 8650

Environment
Meter Communications

Resolution
The ION7550 / 7650 v350 Firmware release introduced a new feature called ModGate. When configured, a modbus request is sent through Ethernet using Modbus TCP to the gateway meter over port 502. If this request is addressed with the slave ID of one of the downstream serial devices, the meter forwards the message to that device using Modbus RTU. When the downstream device responds, the gateway meter forwards the response back to the master. Modbus gateway supports an additional slave address of 255 (in addition to 0-247), which sends a packet to the gateway meter only. The figure shows a typical setup:

How to configure ModGate using the ION Setup software:

1) Connect to the ION meter using ION Setup [See FAQ FA212816].
2) Using the Setup Assistant, under Communications > Serial Settings, set the Protocol of the Serial Port in question to Modbus Master. (Also ensure the baud rate, parity are configured properly to that of the daisy chain meters).
3) Close out of the Setup Assistant (and click NO to connect to a different device), and then enter the Advanced Mode by holding CTRL and clicking on the meter.
4) Locate the Modbus Master Options Modules folder and double click it.
5) Double click on the Modbus Master Options 1 module and go to the Setup Registers tab.
6) Select the MMO1 Serial Connection 1 and set it to the Comm port that was configured in Step 2. Click OK.
7) Select the MMO1 ModbusGate Connection and set it to Gateway Enabled - Serial Connection 1. Click OK.
8) Click Send to save and send the configuration to the meter.

Note: For the PM8000 and ION7550/7650, the following procedure can also be used:

1) Connect to the ION meter using ION Setup.
2) Using the Setup Assistant, under Communications > Serial Settings, set the Protocol of the Serial Port in question to Modbus Master. (Also ensure the baud rate, parity are configured properly to that of the daisy chain meters).
3) (If using PM8000) Select Basic Ethernet > TCP/IP and set the Modbus Gateway to the Serial Port in question.
3) (If using ION7550/7650) Select Network Settings > TCP/IP and set the Modbus Gateway to the Serial Port in question.

How to configure ModGate using Power Monitoring Expert software:

1) Open the meter in Designer
2) Open Communications Setup
3) Right-click on the Comm port in question
4) Double-click on Protocol and set to Modbus Master. (Also ensure the baud rate, parity are configured properly to that of the daisy chain meters). Click OK.
5) Close the Communications Setup window and navigate to Advanced Setup > Core Modules
6) Right-click on Modbus Master Options Modules
7) Double-click on MMO1 Serial Connection 1 and select the Comm port that was configured in Step 3. Click OK.
8) Double-click on MMO1 ModbusGate Connection and set to Gateway Enabled - Serial Connection 1. Click OK.

The meter will now route all incoming traffic on TCP Port 502 to the configured serial port. In order to communicate to the gateway meter itself using Modbus, Unit ID 255 must be used.

The video below depicts how to configure ModGate using the ION Setup software.