I have problems establishing communications (Modbus RTU) between an Omron CP1H PLC using the on board CP1W-CIF01 RS232-Option board and a Campbells Scientific CR10X Data Logger which can be configured as a Slave Device.

Do any of you people have experience in establishing this communication link in the past.
I would appreciate your assistance greatly.

Padraig O'Murchu.
Brightview Technology Ltd.,
Chapel Road, Ovens, Co.CORK,
IRELAND.

e-mail [email protected]

 

No experience, but I looked at the CR10x manual and it appears pretty straightforward Modbus.

- runs Modbus RTU, not Modbus ASCII
- supports function 03 read holding registers (does not 04 support read input registers)
- floating point (FP) format
- input locations 1, 2, 3 are in successive registers from 40001 and up (skipping even numbers because of FP format)
- RS-232
- slave node address is configurable, not clear whether it defaults to 1 or not. Zero disables slave. Something worth checking.

What happens when you poll it with one of the PC Modbus test masters like Simply Modbus or Modscan32?