Configuring the meter as an Ethernet gateway using ION Setup

The meter can function as an Ethernet gateway, allowing Ethernet access to serial devices connected to the meter’s RS-485 serial communications port.

You must install the serial Modbus slave devices, configure them and connect them to your Ethernet-connected Modbus gateway meter. Ensure that each serial device is configured to communicate over Modbus with the same baud rate and parity as the gateway device, and that each device, including the gateway, has a unique unit ID.

The only configuration required for the meter to function as a gateway is to set the serial port’s mode. You can configure other settings, depending on your requirements and network.

NOTE: The protocol of the serial port must be set to Modbus RTU or Jbus for the meter to function as a gateway.

Start ION Setup and connect to your meter.
Open the Advanced Serial Settings screen in the RS-485 Comm Setup folder.
Set Mode to Master Mode to enable the gateway feature or to Slave Mode to disable it.
Set Modbus Broadcast to Enabled if you want broadcast messages to be forwarded to the connected slave devices.
Configure the other advanced parameters required by your system.
Click Send to save your changes to the meter.

Use the meter webpages if you want to adjust the maximum number of Modbus TCP connections allowed.

Modbus Ethernet gateway settings available using ION Setup

Parameter	Value	Description
Response Timeout	0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10	Set the time the gateway meter waits for an answer from a downstream serial device before generating an exception response.
Delay Between Frames	0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100	The minimum time in milliseconds between the end of a received response and the beginning of a new request. Set this parameter to help improve communications between the gateway and downstream slave devices with slower response times.
Silent Interval Extension	0 – 15	Set this parameter to extend the silent interval (used to mark the end of a Modbus packet) beyond the default 3.5 characters defined in the Modbus standard. After the defined character time elapses without a new character, the gateway meter treats the next character as the start of a new message.

Parameter

Value

Description

Response Timeout

0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Set the time the gateway meter waits for an answer from a downstream serial device before generating an exception response.

Delay Between Frames

0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100

The minimum time in milliseconds between the end of a received response and the beginning of a new request.

Set this parameter to help improve communications between the gateway and downstream slave devices with slower response times.

Silent Interval Extension

0 – 15

Set this parameter to extend the silent interval (used to mark the end of a Modbus packet) beyond the default 3.5 characters defined in the Modbus standard. After the defined character time elapses without a new character, the gateway meter treats the next character as the start of a new message.

NOTE: These are advanced settings that you can adjust if you have communication errors when communicating through the gateway to the downstream serial devices. They only apply if the meter is functioning as a gateway, and you should only change these settings if you have an advanced knowledge of Modbus communications and your communications network.