Despatch Protocol Plus Modbus Communications User Manual

E-102 p.n. 143896 A-51643 Rev. 6 10/06/03 Modbus User's Programming Manual For Despatch ProtocolTM Plus

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 4 3. Looking into the back of the controller with the connector terminal strips at the bo

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 5 2.4.2 Communication Card Jumper Settings 1. Turn off power to the controller. 2. Remo

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 6 3 Register and I/O Mapping 3.1 Unmapped and Reserved Registers Reserved and NA registe

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 7 Table 4: ProtocolTM Plus Discrete Output Address Map Data Address Hex Address Descriptio

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 8 3.5 Input Register Assignments Input registers are intended for read only inform

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 9 149 95 Events Status 0 - $F 0 Bits 0-3 = Events 1-4. Bit value: 0 = Off, 1 = On 150 96

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 10 3.6 Holding Register Assignments Holding registers are intended for information and fu

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 11 31 1F Control Type Control[Ctrl] 1 or 2 (Note 1) 0 = Heat, 1 = Cool, 2 = Heat/Cool. H/C

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 12 421 1A5 Segment 4 Ramp Event 1-4 Setup Seg-4 Ramp[Event1-4] 1 or 2 (Note 1) Bits 0-3

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 13 774 306 Sunday Run Mode Auto Start Sun[Mode] 1 or 2 (Note 1) 0=Off, 1=Manual, 2=Timer,

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 i Revision History Rev. Date Description 0 10/6/1998 Original Release 1 01/25/1999 Major r

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 14 1152 -- 1159 480 -- 487 Reserved for factory use 1160 -- 1183 488 -- 49F Illegal, A

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 15 4 Application Operations This section defines application operations in Protocol

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 16 An example is the Manual Setpoint and Manual High Limit Setpoint holding registers. I

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 17 REGISTER ADDRESS REGISTER DESCRIPTION $0000 COMMUNICATIONS ACCESS CODE $0005 KEYPAD LO

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 18 4.6 Event Setup Values For Manual, Timer, and Profile events setup, the corres

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 19 1. Send an individual function code 08, sub-function 10 queries (clear communication c

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 20 5 Function Set Details This section details the Modbus functions supported in the Pro

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 21 15 Return Slave No Response Count Number of messages addressed to the slave for wh

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 22 Response The output status in the response is packed as one output per bit of the data

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 23 Number of outputs hi $00 Number of outputs lo $07 CRC $---- Response The input statu

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 ii Table of Contents 1 OVERVIEW ...

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 24 Number of registers hi $00 Number of registers lo $03 CRC $---- Response The register

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 25 Starting address lo $09 Number of registers hi $00 Number of registers lo $01 CRC $----

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 26 Field Name Data Slave address $0E Function $06 Register address hi $00 Register address

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 27 high order bits and the second byte the low order bits. Next, the actual

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 28 5.3 Diagnostics and Support Description for ProtocolTM Plus All of the diagnostic

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 29 Query Response Field Name Data Field Name Data Slave address $02 Slave address $02 Func

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 30 Table 11: ProtocolTM Plus Diagnostic Register Bit Assignment Bit # Description 0 NA 1 N

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 31 addressed to the slave are monitored, but no action is taken and no respon

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 32 Query Response Field Name Data Field Name Data Slave address $09 Slave address $09 Func

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 33 Function $08 Function $08 Sub-function hi $00 Sub-function hi $00 Sub-function lo $0E S

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 iii 5.1 FUNCTION SET OVERVIEW ...

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 34 Data hi $00 Data hi $00 Data lo $00 Data lo $03 CRC $---- CRC $---- 5.3.2 [17] Report

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 35 5.4 Exception Response Description Except for broadcast messages, when a master

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 36 No. of Registers Lo $08 CRC $---- Exception Response Format Field Name RTU Example

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 37 6 Modbus Protocol Quick Reference This section highlights portions of the Modbu

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 38 Without Parity Checking Start D0 D1 D2 D3 D4 D5 D6 D7 Stop Stop 6.2.3 Error Checking

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 39 6.5 Data Field The data field contains additional information that the slave

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 40 Figure 6 CRC Flowchart 6.7 Field Contents in Modbus Messages The following tables s

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 41 Query Field Name RTU Example Data Description Header > 3.5 idle characters Start cha

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 42 7 Programming Example and General Hints This section provides an example of Micr

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 43 'initialize the CRC register: CRCValue = 65535 For i = 1 To MLength 'thi

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 iv 6.7.1 The Byte Count Field ...

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 44 'set the Settings to select Baud Rate, Parity, Data bits, and Stop bits. 'Not

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 45 CRCWord = GetCRC(TxMessage) 'add the CRC bytes to the message: TxMessage = TxMess

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 46 'can be calculated before the TxMessage is sent, when RxMessage contains &

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 47 7.2 Additional Communications Troubleshooting Hints Communications problems occur prim

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 v

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 1 1 Overview 1.1 Purpose This document provides all application specific information nec

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 2 2 Communications Specifications 2.1 Support Specifications Device Support: Slave only.

Chromalox Instruments and Controls A-51643 Rev. 6 10/06/03 3 Figure 2: RS422A Wiring (4 wire) Figure 3: RS485 Wiring (2 wire) 2.4 Communication Ca