disable modbus error checking

[acolbourn]

Hey,

I am trying to connect to an Omega ir2c series temperature logger without much success. I just talked to Omega and they think the problem is that the amount of data that this series outputs doesn't match the normal modbus amount so I get modbus exception code 3 (which basically just means illegal data value).  I need to try disabling error checking for the standard labview modbus drivers but can't figure out a way.  Any ideas?  

Thanks

[MarcoMauri]

Just a couple of comments:

- Exception code 2 means "A value contained in the query data field is not an allowable value for the slave". ( From http://modbus.org/docs/PI_MBUS_300.pdf page 96).

Are you using function 24? (see page 70 about how this can cause exception code 3)

- "they think the problem is that the amount of data that this series outputs doesn't match the normal modbus amount": ...should not be the case, provided the device is MODBUS compliant.

Regards

Marco

[acolbourn · Accepted solution]

Just doing a follow up on this.  I basically ended up abondoning Modbus and using the companies Newport protocol instead.  Then it worked really easily.  I'm pretty sure the way they built their modbus commands was causing the error and wasn't standardized.