Honeywell UDC2800 User Manual

Data Field:
In a normal response, the responder may return data or statistics in
the data field. In an exception response, the responder returns an
exception code in the data field. This defines the responder condition
that caused the exception.
Query
Example: Internal responder error reading 2 registers starting at
address 1820h from responder at responder address 02.
02 03 18 20 00 02 CRC CRC
Response
Example: Return MSB in Function Code byte set with responder
Device Failure (04) in the data field.
02 83 04 CRC CRC
Table 13-1: 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 no
within range.
428
Chapter 13 - Modbus Communication Exception Codes

Honeywell UDC2800 Specifications

General

Control Modes	PID, ON/OFF, Manual
Mounting	Panel Mount
Display	Dual 4-digit LED
Input Types	Thermocouple, RTD, mA, mV, V
Output Types	Relay
Power Supply	100-240 VAC, 50/60 Hz
Communication	RS-485 Modbus RTU
Enclosure Rating	NEMA 4X