labview error -389112 (I can't write modbus holding registers)

[IñigoP]

Hello to everyone,

I'm trying to communicate a cRIO-9039 with a S7-300 using modbus tcp. The thing is that I can read the values from the input registers in the PLC, but when I try to write in the holding registers, I obtain this error:

"Error -389112 the modbus slave does not accept the data address contained in the query. Function 16"

I add the function block on the snapshots.

Do you have any suggestions?

[JensG69]

Not all register addresses have to exist on a modbus slave, so you obviously try to send data to an invalid register address. Or you try to write to a address that you are not allowed to write to.

Regards, Jens

[IñigoP]

Hello Jens,

I've tried to communicate with qmod Master and I obtain an error also (images attached). I've tried to write single and multiple registers, but it says that the data is invalid. Could it be that the registers are write-protected?