User`s manual

Watlow Controls Communications Guide 17
Messages with the wrong format, timing or CRC are ignored. A read command sent
to an inactive parameter returns 0x0000.
Example:
Exception 01 - Command 02 is not supported.
Sent: 01 02 00 01 00 02 A8 0B
Received: 01 82 01 81 60
Example:
Exception 02 - The parameter at register 45 (0x002D) is inactive.
Sent: 01 06 00 2D 00 01 D8 C3
Received: 01 86 02 C3 A1
Example:
Exception 03 - Cannot write 12,000 (0x2EE0) to register 7, out of range,
illegal data value.
Sent: 01 06 00 07 2E E0 24 23
Received: 01 86 03 02 61
Special Modbus Functions
The following are Modbus registers with special
functions: 24, Disable Non-volatile (system)
Memory; 106, Alarm Status Output 2; 110, Alarm
Status Output 3; 114, Alarm Status Output 4; 200,
Auto-Manual Operation Mode; 311, Clear Input
Errors; 331, Clear Alarms; 332, Silence Alarms.
A "0" indicates an inactive state. Send "1" to the
register to activate the function. It will automatically
reset to "0" when the function is complete. See your
User’s Manual for detail on your specific model.