Honeywell UDC2500 manual General Information, Non-volatile Memory Retention

Modbus Read, Write and Override Parameters plus Exception Codes

10 Modbus Read, Write and Override Parameters plus Exception Codes

10.1 Overview

Introduction

This section contains information concerning Reading, Writing, and Overriding parameters in this instrument. There are two types of parameters:

•Data Transfer—These parameters include reading control data, option status, and reading or changing setpoints.

•Configuration Data—All the configuration data is listed in the order in which it appears in the controller.

Each type of parameter has the identifying codes listed with it.

What's in this section?

The following topics are covered in this section.

	TOPIC	See Page
10.1	Overview	189
10.2	Reading Control Data	190
10.3	Read Options Status	191
10.4	Miscellaneous Read Onlys	192
10.5	Setpoints	193
10.6	Using a Computer Setpoint (Overriding Controller Setpoint)	194
10.7	Configuration Parameters	195
10.8	Modbus RTU Exception Codes	218

General Information

Non-volatile Memory Retention

•This controller uses non-volatile memory to store configuration data. These memories are guaranteed to retain data for a minimum of ten years as long as the data is not written and erased more than 10,000 times. In order not to exceed this number, it is strongly recommended that configurations which change rapidly such as Computer Setpoint use the Override feature which does not affect non-volatile memory.

4/07 UDC2500 Universal Digital Controller Product Manual 189