Trying to get infos from a Voltmeter connected to a MODBUS

[StageAge54]

Hello friends.
I am using a PLC communicating with an UAC CB 01RS4.

What I want to achieve is an meter MODBUS measuring the volt and amp value of a load, connected to a PLC via Modbus, this PLC is connected to a computer via ethernet.
I managed to establish communication but didn't suceed. Indeed, All attempted sessions are fails and the status is 3  - Connection exists, but there is an error in the MODBUS commands.
I have added the MODBUS module to the PLC on UniLogic, and all informations (Modbus panel, baud rate, data bit....) are correct.

Then I've added a Master -> 'registers periodic' -> the modbus communication is the UAC-CB-RS4 and the adress is 5000 (which is the adress register of the Voltage measurement content (for the automate). I also tried to add a slave but still I have the same errors.

If you have any clue on why I have a connection but the MODBUS command has errors, please tell me 😀.

Thank you very much !!

 

 

[Gabriel Franco]

I suggest to double check wiring, network configuration (ID, baud and so on) on the meter side and register numbering, response timeout.

Also, first try using a Modbus software.

Any chance that 5000 is hex?  If so, set decimal address.

[kratmel]

Please post meter model name plate or pdf manual.

Some models have non modbus protocol on board.

[Ausman]

Gabriel and Kratmel, does Unistream stuff also do the register number offset of 1 that Vision does?  Perhaps this is the issue?

And Stage, trial your comms using a PC first, then once proven transfer the known good parameters to the PLC's commands.