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5 exception responses, 6 phrases, abbreviations & acronyms, Modbus – AERCO Modbus Communications Manual User Manual

Page 11: Communication, Gf-114

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Chapter 1

MODBUS

Communication

GF-114

Introduction & Description

USER MANUAL

OMM-0035_0C

05/18/12 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288

Page

11 of 200

1.5 EXCEPTION RESPONSES

With the exception of Broadcast Messages, queries transmitted by the Master expect a normal

response from the addressed Slave on the network. However, if the addressed Slave cannot

process or interpret the message, it will respond with one of the Exception Codes listed in Table

1-4.

Table 1-4: Minimum Exception Code Set

Exception Code

Description

Comments

01

Illegal Function

The function code received is not valid or

is not supported.

02

Illegal Data Address

The data address received is invalid or is

not accessible due to security setting.

03

Illegal Data Value

The data value received is not valid

1.6 PHRASES, ABBREVIATIONS & ACRONYMS

The phrases, abbreviations and acronyms used in this manual are listed in Table 1-5.

Table 1-5: Phrases, Abbreviations and Acronyms

Phrase, Abbreviation

or Acronym

Meaning

ACS

AERCO Control System

ASCII

American Standard Code for Information Interchange

BAS

Building Automation System

Baud

Bits per Second (bps)

BMS (BMS II)

Boiler Management System (Boiler Management System II)

C-More Controller

(or Control Box)

A control system developed by AERCO International and currently

used in all Benchmark and KC Series product lines

EMS

Energy Management System

FDX

Full-Duplex

HDX

Half-Duplex

Hex

Hexadecimal Number (0 - 9, A - F)

I/O Box

Input/Output (I/O) Box currently used on all Benchmark and KC

Series products

LSB

Least Significant Byte

Modbus®

A serial, half-duplex data transmission protocol developed by AEG

Modicon

MSB

Most Significant Byte

RS232

A standard for serial, full-duplex (FDX) transmission of data based

on the RS232 Standard

RS422

A standard for serial, full-duplex (FDX) transmission of data based

on the RS422 Standard

RS485

A standard for serial, half-duplex (HDX) transmission of data

based on the RS485 Standard

RTU

Remote Terminal Unit