Slave Master RTU Timeout

[mwcmwc12]

Hi Christian:

I cannot get the latest version 1.2.1.42 from the VIPM to work in Serial Master RTU. Every time I attempt to read a holding register, it shows error 0x56 timeout. I am trying to communicate to a Test Equity Temp Chamber with a F4T controller trying to read holding register 2782.

I tried 2 alternatives and they both work: 1.) An external (non-Labview) program "modbus poll" and it works with the same setup.

2.) Earlier version of the modbus API version 1.2.1 from here: http://www.ni.com/example/29756/en/

Seems like someone else was seeing this issue as well:

https://forums.ni.com/t5/LabVIEW/Modbus-serial-communication/td-p/3746411?profile.language=en

Regards,

Mike

[djacob91]

Hello @mwcmwc12 ,

Did you find a solution for this. I am also getting error 56 intermittently while polling registers continuously. I also use 1.2.1.42 and Modbus serial RTU.

Regards
Jacob

[Sinaisalelkar]

Same problem error56 what is solution for it
I installed ni modbus library but still not communicating