Illegal functions s 0 n 2

[karthik]

Why am I getting the error the error "Illegal functions s 0 n 2". I have a tag having a valid register address tied to it. This tag is attached to an analog numeric. When I enter input I get the above error some times and some times it wont complain. What could be the reason?

[Chris T.]

Hi karthik,
We see this very frequently when an incorrect datatype is being used and what you write crosses a threshold. For example, in modbus you have a controller that has 16 bit registers and you try to force the write of a 32 bit register into it. This only happens if the controller does some kind of validation.
It also can be that your controller does not support multiple write requests and it is trying to write to registers (similar to above).

These can be a bit tricky to pin down. If this is over Ethernet i suggest using wireshark as you can see the exact reply from the controller and not what the iX driver is reporting. It is possible that the controller transmits a more detailed error over Ethernet that can help you narrow this down.