Writing to Modbus from FX30

Octave
1

Hello everyone,

I am trying to write to an IO board using modbus, and I am having trouble writing to a digital output. The modbus address for these inputs are 00001-00006, and I can read them using Coil as the starting address as shown below.

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In the Modbus guide ( Modbus Guides (octave.dev)) it is clear how to write to a Holding Register (HLD) as shown below.
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Here, to write to the analog output, I use the HLD as the starting address and the “address” field acts as the offset. I think I could write to the digital output if I knew the three letter code, and I think this is it shown below.
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According to this page on the documentation, DO should be the code used as the the “type”. Modbus Reference (octave.dev)
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Thanks,
Wilson Teachey

2

Hi Wilson,

Your question is not very clear, but I confirm you that “DO” is the correct type for Coils (also known as Digital Output).

Let me known of you need any further information.

3

Hello Guillaume,

Sorry the question was not clear. The “DO” code was the primary question that I had. I got it working this morning, but I’m not sure what changed to make it work.

Thanks,
Wilson Teachey

4

Thanks for the information!

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