Honeywell HC900 - Pre-Installation Planning; Overview

Modbus RTU Exception Codes
Introduction
Revision 13 HC900 Process Controller Communications User Guide 41
April 2017
Table 5-1 Modbus RTU Data Layer Status Exception Codes
Exception
Code
Definition
Description
01
Illegal Function
The message received is not an allowable action for the
addressed device.
02
Illegal Data Address
The address referenced in the function-dependent data
section of the message is not valid in the addressed
device.
03
Illegal Data Value
The value referenced at the addressed device location
is not within range.
04
Slave Device Failure
The addressed device has not been able to process a
valid message due to a bad device state.
06
Slave Device Busy
The addressed device has rejected a message due to a
busy state. Retry later.
07
NAK,
Negative Acknowledge
The addressed device cannot process the current
message. Issue a PROGRAM POLL to obtain device-
dependent error data.