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AlexG

Reading Output Coils via Modbus

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Vision 280

Output coil O49

I try to read coil status via Modbus (Kepware).

In Help address must started from 000000.I try 000049 and 005049, but its not work. Help...

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Why from 0000?!

Please check the Slave address table for Standard Vision Division (VisiLogic > FB Modbus > Help > Slave addressing). The start address for outputs is stated there as 5000.

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I work via Kepware.

5 digit addressing vs. 6 digit addressing.

In my case O50 (Unitronics) => 005051 (KepServer). Its work.

For example: MI18(Unitronics) =>400019 (KepServer)

ML4(Unitronics) =>405109 (KepServer) (must calculate addres according to type).

Very bad that is not table transformation addresses (SI,SB,O,I,T etc to Modbus addresses via KepServer)

Thanks.

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What you've found with Kepware actually makes sense. Kepware is following the strict Modbus addressing scheme, which starts counting at 1. Unitronics starts counting at 0, so you have to add 1 to all your address requests.

I've run into this before. I know it's a pain in the butt, but that's the way it is.

Cara - it would be good if the Modbus Slave Addressing tables Help were updated to include an example of working with SCADA Modbus packages.

Joe T.

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