NOVUS N1040i Indicator - Manual (Page 3)

code in case of an invalid request. Response frames containing error codes
have the most significant bit of the Modbus command set (the value 80H is
added to the response).
If a WRITE command sends an out-of-range value to a parameter, the
indicator will clamp the value to the parameter range limits, replying with a
value that reflects these limits (maximum or minimum value allowed for the
parameter).
The indicator ignores broadcast READ commands; the indicator processes
only broadcast WRITE commands.
Error Code Error Description
01 Invalid Command
02 Invalid Register Number or out of range
03 Invalid Register Quantity or out of range
Table 3 – Exception response error codes