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What I/A Series G3 object can be used to retrigger a write a value to a Modbus controller?

Issue

What I/A Series G3 object can be used to retrigger a write a value to a Modbus controller?

Environment

I/A Series G3, Modbus

Cause

Various Modbus controllers require the rewrite of values to maintain use of remote values versus local values.  This fallback mechanism allows the local Modbus controller to maintain control in the event of a BMS controller failure or loss of communications.

Resolution

The I/A Series G3 Modbus driver utilizes Modbus preset components to perform the rewrite function.  Presets allow writing preset values to the target addressed data items upon right-click action (command). If required, the “Write” action of any preset container can be linked into other control logic.

For example, the “Trigger” slot of a TriggerSchedule can be linked into a ModbusClientPresetRegisters container component for periodic writes of child registers defined under the parent.  The same is also true using a periodic trigger object found in kitControl.  Preset components can be found in the modbusAsync palette and modbusTcp palette in the “Presets” folder.

Note: Modbus client preset components are not proxy points or proxy extensions.  Modbus client preset components are not polled and do not read data from the device.  Modbus client preset components are only used to write data to the device. Presets exist for both Modbus coils and holding registers.

Reference the I/A Series G3 Modbus Guide (About Modbus preset components) included with G3 documentation for more details.

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Last update:
‎2018-09-10 01:05 PM
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