question

heei avatar image
heei asked

Problem reading modbus from Cerbo GX

Hello,

We have a problem reading modbus registers on a Cerbo GX from a PLC.

When trying to read from unit id 226, which is in the list of available services, we get this error message:

"Error processing function code 3, unit id 255, start address 257, quantity 68, src 192.168.11.11: Modbus address 257 is not registered"

Note that the error message says unid id 255, not 226.

Unit id 255 isn't valid either, is it?

Has anyone experienced this issue?



cerbo gxModbus TCP
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ijeamaka-omayeka avatar image ijeamaka-omayeka commented ·

I'm currently having same issue:

CCGX firmware version: v2.73


The error code keeps popping up


ERROR "Error processing function code 3, unit id 126, start address 40000, quantity 2, src 192.168.1.116: Modbus address 40000 is not registered"

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1 Answer
wkirby avatar image
wkirby answered ·

There is no unitID 255.
What firmware version are you running on the CerboGX?
The latest version according to the lastes modbus spreadsheet (v2.70) does not have register 257.
Register 259 is the first register available for com.victronenergy.battery (I presume you are trying to read the data from a battery monitor connected to VE.Direct port 1).
Also then, there are only 64 registers to read, you seem to be attempting to read 68 registers.

Try to read one regiser maybe register 259 from unitID 226 and prove if that works, then work up to what you need.

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