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Using Modbus Tester to control an ION meter

Published date: 04 November 2019

This article discusses how to control an ION module and in turn an ION meter.  This includes resetting, triggering and changing state of a module registers.

Product Line
Applies to all ION meters (7330, 7650RTU, 8600, ...).

Modbus Tester or any other Modbus program or device with write capability.
Refer to Modbus Map for ION Meters document that lists each module (ION register) and its corresponding Modbus register based on the ION module number.

Controlling an ION meter by sending commands using Modbus protocol.  The commands can be written to the following modules:

  • External Numeric
  • External Boolean
  • External Pulse

For demonstration purposes, a value will be written to External Numeric 1 and 4 modules.  Writing to External Boolean and External Pulse modules follow the same procedure.

1. Determine Modbus addresses by referring to Modbus Map for ION Meters document

  • External Numeric 1:     42301 - 42302
  • External Numeric 4:     42307 - 42308
Note that each address consists of two 16 bit registers.


2.  Configure Tester and write (any value) to first set of registers.
Note that the IP address has to match the IP address of the ION meter that is being written to.  Also by default the slave address for an ION meter is 100.

3.  Configure Tester and write (any value) to second set of registers:

4.  Verify the above two operations have completed successfully by reading all registers:

For more information on how to use Modbus Tester and where to download it see FA180037.

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