OPTO 22 SNAP Integration Manual

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SNAP I/O MODULE

INTEGRATION GUIDE

Form 0876-160623—June 2016

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Phone: 800-321-OPTO (6786) or 951-695-3000

Fax: 800-832-OPTO (6786) or 951-695-2712

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SNAP I/O Module Integration Guide Form 0876-160623—June 2016

The information in this manual has been checked carefully and is believed to be accurate; however, Opto 22 assumes no responsibility for possible inaccuracies or omissions. Specifications are subject to change without notice.

Opto 22 warrants all of its products to be free from defects in material or workmanship for 30 months from the manufacturing date code. This warranty is limited to the original cost of the unit only and does not cover installation, labor, or any other contingent costs. Opto 22 I/O modules and solid-state relays with date codes of 1/96 or newer are guaranteed for life. This lifetime warranty excludes reed relay, SNAP serial communication modules, SNAP PID modules, and modules that contain mechanical contacts or switches. Opto 22 does not warrant any product, components, or parts not manufactured by Opto 22; for these items, the warranty from the original manufacturer applies. Refer to Opto 22 form 1042 for complete warranty information.

Wired+Wireless controllers and brains are licensed under one or more of the following patents: U.S. Patent No(s). 5282222, RE37802, 6963617; Canadian Patent No. 2064975; European Patent No. 1142245; French Patent No. 1142245; British Patent No. 1142245; Japanese Patent No. 2002535925A; German Patent No. 60011224.

Opto 22 FactoryFloor, groov, Optomux, and Pamux are registered trademarks of Opto 22. Generation 4, groov Server, ioControl, ioDisplay, ioManager, ioProject, ioUtilities, mistic, Nvio, Nvio.net Web Portal, OptoConnect, OptoControl, OptoDataLink, OptoDisplay, OptoEMU, OptoEMU Sensor, OptoEMU Server, OptoOPCServer, OptoScript, OptoServer, OptoTerminal, OptoUtilities, PAC Control, PAC Display, PAC Manager, PAC Project, PAC Project Basic, PAC Project Professional, SNAP Ethernet I/O, SNAP I/O, SNAP OEM I/O, SNAP PAC System, SNAP Simple I/O, SNAP Ultimate I/O, and Wired+Wireless are trademarks of Opto 22.

ActiveX, JScript, Microsoft, MS-DOS, VBScript, Visual Basic, Visual C++, Windows, and Windows Vista are either registered trademarks or trademarks of Microsoft Corporation in the United States and other countries. Linux is a registered trademark of Linus Torvalds. ARCNET is a registered trademark of Datapoint Corporation. Modbus is a registered trademark of Schneider Electric, licensed to the Modbus Organization, Inc. Wiegand is a registered trademark of Sensor Engineering Corporation. Allen-Bradley, CompactLogix, ControlLogix, MicroLogix, SLC, and RSLogix are either registered trademarks or trademarks of Rockwell Automation. CIP and EtherNet/IP are trademarks of ODVA.

groov includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit. (http://www.openssl.org)

All other brand or product names are trademarks or registered trademarks of their respective companies or organizations.

Opto 22 Automation Made Simple.

SNAP I/O Module Integration Guide

Table of Contents

Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

SNAP I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Choosing SNAP I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Communicating with SNAP I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

About this Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

For Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 2: Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Mechanical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

All Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Using Modules with an Opto 22 Mounting Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Using Modules without an Opto 22 Mounting Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Electrical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4-Channel Digital Input/Output Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Analog Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Resolution and Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Analog Module Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Other Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Serial Communication Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

SNAP Module Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Chapter 3: Communication Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Serial Protocol (Binary or ASCII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Module Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Point Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Serial Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Serial Protocol Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Message Field Definitions—Serial Protocol Packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

About Data Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Calculating a Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Calculating a CRC16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Serial Message Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Command Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

SNAP I/O Module Integration Guide iii

iii

Response Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

ARCNET Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Point Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

ARCNET Protocol Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Message Field Definitions—ARCNET Protocol Packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

ARCNET Message Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Command Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Response Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Global Protocol Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Product Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Message Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Error Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Module Types, Channel Modes, and Point Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Analog Input Modules with Four Points or Less . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Analog Input Modules with More than Four Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Analog Output, Serial, and High-Density Digital Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Chapter 4: Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Command List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Command Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Read Number of Received Data Bytes Waiting Command 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Read Channel Mode . . . . . . . . . . . . . . . . . . . . . . .Command 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Set Channel Mode . . . . . . . . . . . . . . . . . . . . . . . . Command 3A . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Set Point Configuration . . . . . . . . . . . . . . . . . . . .Command 3C . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Powerup Clear—Current Modules . . . . . . . . . .Command 40 . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Powerup Clear—Legacy Modules. . . . . . . . . . .Command 41 . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Command 42 . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Read Amount of Unused Space in Transmit Buffer Command 42 . . . . . . . . . . . . . . . . . . . . . . . 34

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Save Current Module Configuration in EEPROM Command 45 . . . . . . . . . . . . . . . . . . . . . . . . . 34

SNAP I/O Module Integration Guide

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Identify Module Type . . . . . . . . . . . . . . . . . . . . . . Command 46 . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Set Serial Port Configuration . . . . . . . . . . . . . . . Command 47 . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Set Serial Port Response Delay . . . . . . . . . . . . . Command 48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Read Module Firmware Version . . . . . . . . . . . . Command 49 . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Group Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 52 . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Group Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 52 . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Read Status—Latches Not Cleared . . . . . . . . . Command 52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Receive Serial Data . . . . . . . . . . . . . . . . . . . . . . . . Command 52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Group Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 53 . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Read Status—Latches Cleared . . . . . . . . . . . . . Command 53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Read HDD Counters—Counters Not Cleared Command 54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Read HDD Counters—Counters Cleared . . . . Command 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Channel Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Channel Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Set TPO Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 57 . . . . . . . . . . . . . . . . . . . . . .

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Write Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

. . . . . . 42

SNAP I/O Module Integration Guide v

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Read Status (TPO, Inhibit On/off) . . . . . . . . . . . .Command 58 . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Clear Serial Port Receive Buffer . . . . . . . . . . . . . .Command 63 . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Read Serial Port CTS . . . . . . . . . . . . . . . . . . . . . . . . Command 66 . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Set Serial Port RTS . . . . . . . . . . . . . . . . . . . . . . . . . .Command 66 . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Clear Serial Port RTS . . . . . . . . . . . . . . . . . . . . . . . .Command 66 . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Read Serial Module Info . . . . . . . . . . . . . . . . . . . .Command 69 . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Read Serial Port Configuration . . . . . . . . . . . . . .Command 71 . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Write Serial Port Configuration . . . . . . . . . . . . . .Command 71 . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Write Serial Port Configuration and Store to Flash Command 71 . . . . . . . . . . . . . . . . . . . . . . . 48

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Receive Line of Serial Data . . . . . . . . . . . . . . . . . .Command 72 . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Send & Receive Serial Data . . . . . . . . . . . . . . . . .Command 73 . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Send Serial Data . . . . . . . . . . . . . . . . . . . . . . . . . . . Command 74 . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Command Data Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Response Data Received . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

SNAP I/O Module Integration Guide

Chapter 2

1: Introduction

This guide provides information needed by original equipment manufacturers (OEMs) and others who use SNAP input/output (I/O) modules without a SNAP serial or Ethernet-based brain.

This guide also applies to OEMs using SNAP I/O modules with an Opto 22 OEM brain such as the SNAP-ARL-ASDS. I/O module physical and electrical interfaces and specifications are included, as well as details of the protocols necessary for communication.

SNAP I/O Modules

SNAP I/O modules were designed as OEM products and also as components of Opto 22 SNAP I/O systems. SNAP module types include:

• Four-channel SNAP digital modules—Each module provides four input or four output points. AC and DC models are available with a wide variety of voltages; dry contact models are also available.

• SNAP high-density digital modules, each providing more than four input or output points.

• SNAP analog modules—Analog modules provide

one to 32 input or output points, depending on the model. Inputs include voltage, current, thermocouple, RTD, and others. Outputs are current, voltage, or time-proportional output.

• SNAP serial communication modules, each with two channels for RS-232 or RS-485/422 communication, depending on the model. (Other SNAP serial modules are not documented in this guide; see their data sheets for information.)

SNAP I/O Module Integration Guide 1

SNAP I/O MODULES

Choosing SNAP I/O Modules

To choose modules for your application, see our website, www.opto22.com, or refer to the following data sheets, which are available on our website. Follow the link below or search on its form number.

Data sheet Form #

SNAP Digital Input Modules Data Sheet 773 SNAP Digital Output Modules Data Sheet 1144 SNAP Analog Input Modules Data Sheet 1065 SNAP Analog Output Modules Data Sheet 1066 SNAP Isolated Analog Input Modules Data Sheet 1182 SNAP Serial Communication Modules Data Sheet 1184 SNAP High-Density Digital Module Data Sheet 1556 SNAP Load Cell Modules Data Sheet 1590 SNAP Power Monitoring Modules Data Sheet 1453 SNAP pH/ORP Module Data Sheet 1416 HART SNAP I/O Modules Data Sheet 2080 SNAP Mechanical Power Relay Output Module Data Sheet 1967

Communicating with SNAP I/O Modules

Many SNAP I/O modules can be used either with or without an Opto 22 mounting rack and with or without an Opto 22 brain.

If you are using a Linux-based OEM brain, you must use an Opto 22 rack, because the brain’s only method of communicating with analog and serial modules is via the ARCNET communication built into the rack.

The following table shows the methods of communication available for each type of module.

Module type Interface or protocol

4-Channel Digital 5 VDC logic (No protocol needed)

Analog

High-density digital ARCNET*

Serial ARCNET*

*When used with a Linux-based OEM brain, communication with analog, high-density digital, and serial modules is via ARCNET on an Opto 22 mounting rack. A driver is available for this brain; see the readme file included with the driver for details.

Serial binary or serial ASCII

ARCNET*

SNAP I/O Module Integration Guide

About this Guide

NOTE: Email messages and phone calls to Opto 22 Product Support are grouped together and answered in the order received.

This guide covers hardware, electrical, and protocol interfaces to SNAP digital, analog, and serial modules. This guide assumes that you are already familiar with the communication protocols you will use.

The following sections are included in this guide:

Chapter 1: Introduction—Information about the guide and how to reach Product Support

Chapter 2: Interfaces—Mechanical interface, including board layout and module mounting; and

electrical interface, including signal, power, ground, and data connections

Chapter 3: Communication Protocols—Details of the serial (binary or ASCII) and ARCNET

protocols used to communicate with SNAP I/O modules, including addressing, communication details, and packet information

Chapter 4: Commands—Complete list of commands and the protocols they are used with, plus

details of the data required for each command.

For Help

CHAPTER 1: INTRODUCTION

If you have problems using SNAP I/O modules and cannot find the help you need in this guide or on our Web site, contact Opto 22 Product Support.

Phone: 800-TEK-OPTO (800-835-6786

toll-free in the U.S. and Canada) 951-695-3080 Monday through Friday, 7 a.m. to 5 p.m. Pacific Time

Fax: 951-695-3017

Email: support@opto22.com

Opto 22 website: www.opto22.com

SNAP I/O Module Integration Guide

FOR HELP

SNAP I/O Module Integration Guide

Chapter 3

2: Interfaces

Mechanical Interface

All Modules

The following figure shows the mechanical interface for all SNAP modules. All dimensions are with reference to pin 1 of the electrical connector.

Using Modules with an Opto 22 Mounting Rack

If you are using an Opto 22 mounting rack, the retention rail is built into the rack. The following graphic shows a mounting rack with the retention rail.

SNAP I/O Module Integration Guide 5

MECHANICAL INTERFACE

IMPORTANT: The mounting rack connector has 24 pins; the module connector has 20 pins. The extra pins on the mounting rack connector prevent misalignment of the module when installing.

Using Modules without an Opto 22 Mounting Rack

If you are not using an Opto 22 rack, lengths of retention rail suitable for mounting four modules or six modules are available from Opto 22 distributors. The rails come in packs of 25:

• SNAP-RETN4B (4-Module retention rail, 25 pack)

• SNAP-RETN6B (6-Module retention rail, 25 pack)

Connectors and PEM nuts can be ordered from the following sources:

RS2-24-GPC Board mount 24-pin connector Adam Tech 909 Rahway Ave. Union, New Jersey 07083 Phone: (908) 687-5000 Fax: (908) 687-5710 Email: info@adam-tech.com

PEM NUT 4-40PC Board mount PEM nut for 4-40 screws Penn Engineering & Mfg 5190 Old Easton Rd. Danboro, PA 18916 Phone: 800-342-5736 Fax: (215) 766-3633 Email: info@pennfast.com

SNAP I/O Module Integration Guide

Electrical Interface

4-Channel Digital Input/Output Modules

The bottom view of the module in the following diagram shows the electrical interface pin assignments for 4-channel digital modules. You read or write to each digital point using simple 5 VDC discrete signals.

CHAPTER 2: INTERFACES

4-channel digital modules require only 5-volt power and TTL level data connections to signals D0 through D3 on pins 2, 4, 6, and 8. Like earlier Opto 22 digital modules, SNAP 4-channel digital modules use low-true logic (also called negative-true logic). A digital input point that is on returns a logic 0 signal. A logic 0 control signal turns on a digital output point.

Most 4-channel digital modules require approximately 50 mA for all four channels. SNAP-ICD5-SW and SNAP-IDC5SW-NC modules require 200 mA. “SNAP Module Power Requirements” on page 10 lists requirements for all modules.

SNAP I/O Module Integration Guide

ELECTRICAL INTERFACE

Notes:

1. Pins 1, 3, 5, and 7 set the module address. See “Module

Addresses” on page 12 for details.

2. An Opto 22 AC37 adapter card connection is shown as

typical. Any RS-485 serial port may be used.

3. Optional shielding may be used to reduce noise on

communications. Shields must not be grounded on both ends of the communication link, but should be grounded on one end only. Do NOT tie shield to signal common or 5 VDC return.

4. Optional COM (common) wire is recommended to

reduce common-mode noise. Note that the COM connection is not connected to Earth ground.

Analog Modules

The following figure shows the bottom view of the module with the electrical interface pin assignments for analog modules.

If you are using the serial protocol, the serial ± connection is 2-wire RS-485. These data lines must be multidropped to corresponding connector pins for each analog module on the bus. Serial data lines must be terminated with a 220 Ohm resistor on the end of the communication network. The host end of the communication line must also be biased and terminated. Since the address range of the modules is 80 through 8F (hex), only 16 modules can be installed per data link.

If you are using ARCNET, NET+ and NET– are the ARCNET connections.

Other mandatory connections to the module are for +5 volt power, 5-volt return, Earth ground, and connections to pins 1, 3, 5, and 7, which set the module’s address. For more information on addressing, see page 11 for the serial protocol or page 17 for the ARCNET protocol.

The diagram below shows a typical serial data link connection to an analog module.

SNAP I/O Module Integration Guide

CHAPTER 2: INTERFACES

Resolution and Range

SNAP analog input modules have approximately 15.5-bit resolution in the nominal range, supporting counts from -25,000 to +25,000. These modules support 10% over range and 10% under range. The following example illustrates resolution and range for a SNAP-AIV module:

Module Channel

mode

SNAP-AIV

0x22 -10 to +10 VDC -11 VDC -10 VDC 0 VDC 10 VDC 11 VDC

0x32 -5 to +5 VDC -5.5 VDC -5 VDC 0 VDC 5 VDC 5.5 VDC

Nominal

range

Under-

range limit

-110% -100% 0% 100% 110%

-27,500 -25,000 0 25,000 27,500

Low

scale

Counts

High

scale

Over-

range limit

SNAP analog output modules have 12-bit resolution, supporting counts from 0 to 4095 for a total of 4096 counts. There are no under-range or over-range limits. Unipolar and bipolar modules both receive zero counts at low scale, as shown in the examples below:

Low scale High scale

Counts

Module Nominal range 0 2047 4095

SNAP-AOV-25

SNAP-AOV-27

0 to +10 VDC 0 VDC 5 VDC 10 VDC

-10 to +10 VDC -10 VDC 0 VDC 10 VDC

Analog Module Power Requirements

See the table on page 10.

Other Modules

Serial communication modules and high-density digital modules must be used with the ARCNET protocol. They cannot be used with the serial protocol.

See the table on page 10 for power requirements.

Serial Communication Modules

IMPORTANT: Commands available for the ARCNET protocol apply only to the following serial communication modules:

• SNAP-SCM-232 Revision A modules (manufactured in June 2003 or after) with firmware R1.1e or higher. These modules support optional RTS/CTS flow control.

• SNAP-SCM-232 modules manufactured before June 2003 with firmware R1.1o. These modules do not support RTS/CTS flow control.

• SNAP-SCM-485-422 modules. (Modules manufactured before June 2003 with the part number SNAP-SCM-485 do not work with the commands in this guide.)

SNAP I/O Module Integration Guide

ELECTRICAL INTERFACE

SNAP Module Power Requirements

Module Requirements Module Requirements

SNAP-IDC5-SW 5 VDC @ 200 mA SNAP-AIPM 5 VDC @ 100 mA

SNAP-IDC5-SW-NC 5 VDC @ 200 mA SNAP-AIPM-3 5 VDC @ 100 mA

SNAP-OMR6-A 5 VDC @ 160 mA SNAP-AIPM-3V 5 VDC @ 100 mA

SNAP-OMR6-C 5 VDC @ 160 mA SNAP-AIR40K-4 5 VDC @ 190 mA

Other 4-ch. digital modules 5 VDC @ 50 mA SNAP-AIR400K-8 5 VDC @ 190 mA

SNAP-IAC-16 5 VDC @ 150 mA SNAP-AIRATE 5 VDC @ 190 mA

SNAP-IAC-A-16 5 VDC @ 150 mA SNAP-AIRATE-HFi 5 VDC @ 210 mA

SNAP-IAC-K-16 5 VDC @ 150 mA SNAP-AIRTD 5 VDC @ 190 mA

SNAP-IDC-16 5 VDC @ 150 mA SNAP-AIRTD-10 5 VDC @ 190 mA

SNAP-IDC-HT-16 5 VDC @ 150 mA SNAP-AIRTD-1K 5 VDC @ 190 mA

SNAP-IDC-32 5 VDC @ 150 mA SNAP-AITM 5 VDC @ 170 mA

SNAP-IDC-32-FM 5 VDC @ 150 mA SNAP-AITM-i 5 VDC @ 200 mA

SNAP-IDC-32D 5 VDC @ 150 mA SNAP-AITM-2 5 VDC @ 170 mA

SNAP-IDC-32DN 5 VDC @ 150 mA SNAP-AITM2-i 5 VDC @ 200 mA

SNAP-IDC-32N 5 VDC @ 150 mA SNAP-AITM-4i 5 VDC @ 150 mA

SNAP-ODC-32-SNK 5 VDC @ 150 mA SNAP-AITM-8 5 VDC @ 200 mA

SNAP-ODC-32-SNK-FM 5 VDC @ 150 mA SNAP-AIV 5 VDC @ 170 mA

SNAP-ODC-32-SRC 5 VDC @ 150 mA SNAP-AIV-i 5 VDC @ 200 mA

SNAP-ODC-32-SRC-FM 5 VDC @ 150 mA SNAP-AIV-4 5 VDC @ 170 mA

SNAP-AIARMS 5 VDC @ 170 mA SNAP-AIV-8 5 VDC @ 170 mA

SNAP-AIARMS-i 5 VDC @ 200 mA SNAP-AIV-32 5 VDC @ 150 mA

SNAP-AIARMS-i-FM 5 VDC @ 200 mA SNAP-AIV2-i 5 VDC @ 200 mA

SNAP-AICTD 5 VDC @ 150 mA SNAP-AIVRMS 5 VDC @ 170 mA

SNAP-AICTD-4 5 VDC @ 150 mA SNAP-AIVRMS-i 5 VDC @ 200 mA

SNAP-AICTD-8 5 VDC @ 170 mA SNAP-AIVRMS-i-FM 5 VDC @ 200 mA

SNAP-AILC 5 VDC @ 120 mA SNAP-AOA-3 5 VDC @ 140 mA

SNAP-AILC-2 5 VDC @ 120 mA SNAP-AOV-5 5 VDC @ 150 mA

SNAP-AIMA 5 VDC @ 170 mA SNAP-AOA-23 5 VDC @ 150 mA

SNAP-AIMA2-i 5 VDC @ 200 mA SNAP-AOA-23-iH 5 VDC @ 150 mA

SNAP-AIMA-4 5 VDC @ 170 mA SNAP-AOV-25 5 VDC @ 150 mA

SNAP-AIMA-8 5 VDC @ 170 mA SNAP-AOV-27 5 VDC @ 150 mA

SNAP-AIMA-32 5 VDC @ 150 mA SNAP-AOA-28 5 VDC @ 150 mA

SNAP-AIMA-i 5 VDC @ 200 mA SNAP-AOD-29 5 VDC @ 150 mA

SNAP-AIMA-iH 5 VDC @ 150 mA SNAP-AOD-29-HFi 5 VDC @ 300 mA

SNAP-AIMA-iSRC 5 VDC @ 200 mA SNAP-SCM-232 5 VDC @ 250 mA

SNAP-AIMV-4 5 VDC @ 170 mA SNAP-SCM-485-422 5 VDC @ 250 mA

SNAP-AIMV2-4 5 VDC @ 170 mA SNAP-SCM-PROFI 5 VDC @ 250 mA

SNAP I/O Module Integration Guide

Chapter 4

3: Communication Protocols

Introduction

Opto 22 4-channel digital I/O modules require no protocol; they are simply read or written to using 5 VDC signals. Analog, high-density digital (HDD), and serial I/O modules, however, are “smart” modules. Each one includes a processor. As shown in the table on page 2, the type of module determines the methods available to communicate with it.

This chapter includes detailed descriptions of the Serial (binary or ASCII) and ARCNET protocols.

Serial Protocol (Binary or ASCII)

Each analog (or HDD or serial) input or output module is actually an addressable analog processor that you can communicate with using either ASCII or binary serial modes. It is this on-module intelligence that makes these SNAP modules such a powerful OEM tool.

Addressing

Each I/O module has its own address. Sixteen modules can be addressed per communications link. Modules are addressed 80 through 8F hex.

Voltage to the module’s pins 1, 3, 5, and 7 determine the address, as shown in the table on the following page.

SNAP I/O Module Integration Guide 11

SERIAL PROTOCOL (BINARY OR ASCII)

Module Addresses

Address (hex) Pin 7 Pin 5 Pin 3 Pin 1

80 Ground Ground Ground Ground

81 Ground Ground Ground +5 Volts

82 Ground Ground +5 Volts Ground

83 Ground Ground +5 Volts +5 Volts

84 Ground +5 Volts Ground Ground

85 Ground +5 Volts Ground +5 Volts

86 Ground +5 Volts +5 Volts Ground

87 Ground +5 Volts +5 Volts +5 Volts

88 +5 Volts Ground Ground Ground

89 +5 Volts Ground Ground +5 Volts

8A +5 Volts Ground +5 Volts Ground

8B +5 Volts Ground +5 Volts +5 Volts

8C +5 Volts +5 Volts Ground Ground

8D +5 Volts +5 Volts Ground +5 Volts

8E +5 Volts +5 Volts +5 Volts Ground

8F +5 Volts +5 Volts +5 Volts +5 Volt

Point Numbers

Opto 22 point numbers on each module start with zero. The points on a four-channel analog input module, for example, are referred to as point 0, point 1, point 2, and point 3.

SNAP I/O Module Integration Guide

CHAPTER 3: COMMUNICATION PROTOCOLS

Serial Communication

Default settings for the serial communication baud rate and protocol are shown in the following table. To change serial port communication settings, use the bits shown in this table in the Data byte of command 47 (see page 35).

Bits 7-6 Reserved -- reserved

CRC method is CRC16 Reverse

with a seed value of 0.

Bit 5 Data Verification

Bit 4 Protocol

Bits 3-0 Baud Rate

0 CRC16

1 Checksum (default)

0 Binary

1 ASCII (default)

0 reserved

1115.2k

2 reserved

3 57.6k

4 38.4k

5 19.2k

6 9600 (default)

7 4800

8 2400

9 1200

A 600

B 300

C reserved

D reserved

E reserved

F reserved

Serial Protocol Details

Unlike earlier Opto 22 protocols (such as mistic), every message in the SNAP I/O serial protocol contains the address of both the source and the destination. A sequence identifier has also been added to keep track of sequences of commands and responses. This provision allows smart devices to perform with reduced communication overhead, resulting in higher performance.

Serial data can be transmitted in binary mode or ASCII mode. ASCII messages contain the same information in the same order as binary messages, but they must start with the > (greater than) character and end with a carriage return character. Each byte of ASCII data is transmitted as the ASCII characters represented in the binary message. For example, binary data represented by 41 hex (the character A) is transmitted as the two ASCII characters 4 and 1.

SNAP I/O Module Integration Guide

SERIAL PROTOCOL (BINARY OR ASCII)

85 01 04 20 01 00 41 EC

Add (in hex): 85+01+04+20+01+00+41 = EC Take the least significant byte: EC

Message Field Definitions—Serial Protocol Packet

Abbrev. Contents Definition/Comments

DEST

SRC Source address of this packet

LEN

PRC Product category

SEQ Sequence ID

MST Message type

CMD / DATA

DVF Data verification

Destination address of this packet

Total number of bytes following the Length byte, excluding DVF and carriage return

Command or Data or both

See “Addressing” on page 11.

For the host source address in an OEM application, use a value of

1. For module addressing, see page 11.

Length calculation starting with Product category and ending with the last byte of the Command/Data fields. For ASCII, divide by 2. The ASCII message is just the binary message (including LEN and DVF) converted to ASCII.

Opto 22-defined classification of the message source. See “Product

Categories” on page 20.

A unique ID assigned by the host application to identify the order of messages. Possible values: 0–255. Each message transmitted from the host should increment the Sequence ID to distinguish it from the previous message. The response sequence ID identifies the message being responded to.

Opto 22-defined classification of the message type. See “Message

Types” on page 20.

Command number, data sent or received, or error code. For error codes, see “Error Responses” on page 20.

Data verification field. Checksum requires 1 byte in binary mode or 2 bytes in ASCII mode. CRC requires 2 bytes in binary mode or 4 bytes in ASCII mode. See “About Data Verification” on page 14.

The ASCII version of the message is simply the binary message converted to ASCII format and then encapsulated between the start-of-message character (>) and end-of-message character (carriage return).

About Data Verification

The data verification field (DVF) is calculated on the complete binary message. (For ASCII, the complete binary message including DVF is converted to ASCII.)

In the serial protocol, SNAP modules allow two types of data verification to be used on message transactions, checksum and CRC16.

Calculating a Checksum

Here is a serial binary message sending a Powerup Clear Command (41) to a module at address 85 hex. The last byte is the checksum; it is calculated as shown:

SNAP I/O Module Integration Guide

CHAPTER 3: COMMUNICATION PROTOCOLS

Calculating a CRC16

CRC16 calculation is more complex. For CRC calculations, the method used is CRC16 Reverse, and the seed (or starting) value is zero. Please see Opto 22 form #270, the Mistic Analog and Digital Command Manual, for more information.

Serial Message Examples

Command Message Format

# Bytes: 1 1 1 1 1 1 1 0–1+ 1 or 2

Serial binary DEST SRC LEN PRC SEQ MST

# Bytes: 1 2 2 2 2 2 2 2 0–2+ 2 or 4 1

Serial ASCII > DEST SRC LEN PRC SEQ MST

NOTE: Do not send another command until you have received a response from the previous command or have waited a reasonable timeout period.

DATA

CMD Data

DATA

CMD Data

DVF

DVF <cr>

Serial Binary Examples. The following is an example of Command 41 (Powerup Clear) sent to

the module at address 85 hex using the serial protocol in binary mode. All numbers are in hex.

DEST SRC LEN PRC SEQ MST CMD DVF

85 01 04 20 01 00 41 EC

This message is a total of 8 bytes. The checksum was calculated by taking the least significant byte of the sum of the hex values:

85h + 01h + 04h + 20h + 01h + 00h + 41h = EC hex

If this message were viewed as a string of characters, not all of the characters would be printable. It would look something like this:

Character

Description

Hex85010420010041EC

à SOH EOT space SOH null A



The next example shows Command 52 (Group Read) used to read the point values on a SNAP-AIV analog input module at address 8A.

DEST SRC LEN PRC SEQ MST CMD DVF

8A 01 04 20 02 00 52 03

The following example shows how to write values to a SNAP-AOV-25 analog output module at address 8B. Command 53 (Group Write) writes two 16-bit values for each point, but only 12 bits are needed (see “Resolution and Range” on page 9). This example sets point 0 to 3.8 volts, which is 1556 counts in decimal, or 614 in hex. Point 1 is set to 8 volts, which is 3276 decimal counts, or 0xCCC.



DEST SRC LEN PRC SEQ MST CMD DATA DVF

8B 01 08 20 06 00 53 0614 0CCC FF

SNAP I/O Module Integration Guide

SERIAL PROTOCOL (BINARY OR ASCII)

Serial ASCII Example. The following example shows Command 41 (Powerup Clear) sent to the

module at address 85 hex using the serial protocol in ASCII mode. All numbers are in hex.

As you can see, the ASCII command is very similar to the binary command in the previous example. Each nibble of binary data has been converted to an ASCII character, and the prefix (>) and suffix (carriage return) have been added. The resulting message totals 18 bytes.

Response Message Format

# Bytes: 1 1 1 1 1 1 0–1+ 1 or 2

Serial binary DEST SRC LEN PRC SEQ MST DATA DVF

# Bytes: 1 2 2 2 2 2 2 0–2+ 2 or 4 1

Serial ASCII > DEST SRC LEN PRC SEQ MST DATA DVF <cr>

Serial Binary Examples. The following shows an ACK response packet received after sending

Command 41 in the example above. This response uses the serial protocol in binary mode, and all numbers are in hex.

DEST SRC LEN PRC SEQ MST CMD DVF

> 85010420010041ECcr

DEST SRC LEN PRC SEQ MST DVF

01 85 03 80 01 01 0B

Again, the checksum is the least significant byte of the sum of the hex values:

01h + 85h + 03h + 80h + 01h + 01h = 10B hex ? 0B hex

The next example is a response to the Command 52 sent above, which read the values of the two points on a SNAP-AIV analog input module. The response returns four 16-bit values, but since the module has only two points, only the upper four bytes are significant.

DEST SRC LEN PRC SEQ MST DATA DVF

01 8A 03 80 01 01 09C4 3F7A 0000 0000 96

The response data indicates that point 0 has a value in counts of 0x09C4, or 2500 decimal, which for a SNAP-AIV module equals 1 volt. (See “Resolution and Range” on page 9.) Point 1 has a value of 0x3F7A, or 16,250 decimal, which equals 6.5 volts.

Serial ASCII Example. The following is an ACK response packet received after sending

Command 41 in the example above. This response uses the serial protocol in ASCII mode. All numbers are in hex.

DEST SRC LEN PRC SEQ MST DVF

> 0185038001010Bcr

SNAP I/O Module Integration Guide

ARCNET Protocol

Addressing

Sixteen modules can be addressed per communications link. Every module is automatically assigned an address when it is plugged into a position on the mounting rack.

The address is an offset of 80 hex added to the module’s position number on the rack (0 through 15 decimal, as shown on the rack, or 0 through F hex). For example, module 12 (decimal) is C in hex, so its address is 8C. The following table shows the address assigned to each module position number.

Module # Address (hex) Module # Address (hex)

080 888

181 989

282 108A

383 118B

484 128C

CHAPTER 3: COMMUNICATION PROTOCOLS

585 138D

686 148E

787 158F

Point Numbers

Opto 22 point numbers on each module start with zero. The points on a four-channel analog input module, for example, are referred to as point 0, point 1, point 2, and point 3.

Communication

The physical connections required for ARCNET communication are built into the Opto 22 SNAP mounting rack. If you are using a SNAP-ARL-ASDS brain, you need to use the Opto 22 rack in order to communicate with analog and serial modules.

SNAP I/O Module Integration Guide

ARCNET PROTOCOL

ARCNET Protocol Details

Message Field Definitions—ARCNET Protocol Packet

Abbrev. Contents Definition/Comments

SRC

DEST

CNT Count The number of bytes following this byte, subtracted from 0x100

OSC OS code

PRC Product category

SEQ Sequence ID

BNK / MST

CMD /

SCMD /

PRT / DATA

Source address of this packet

Destination address of this packet

Bank number and Message type

Command, Subcommand, Port, Data, or combination

For the host source address in an OEM application, use a value of 1. For module addressing, see page 17.

See “Addressing” on page 17.

ARCNET Trade Association-defined vendor code (always DA for Opto 22)

Opto 22-defined classification of the message source. See “Product

Categories” on page 20.

Upper nibble is bank number (for SNAP modules, always 0); lower nibble is Opto 22-defined classification of the message type. See “Mes-

sage Types” on page 20.

Command and optional subcommand number, port if required (usually for serial modules), data sent or received, or error code. For error codes, see “Error Responses” on page 20.

ARCNET Message Examples

Command Message Format

# Bytes: 1 1 1 1 1 1 1 1 0–2 0–1 0–1+

ARCNET SRC DEST CNT OSC PRC SEQ

NOTE: Do not send another command until you have received a response from the previous command or have waited a reasonable timeout period.

Command Examples. The following is an example of Command 41 (Powerup Clear) sent to the

module at address 0x85 using the ARCNET protocol. All numbers are in hex.

SRC DEST CNT OSC PRC SEQ

01 85 FB DA 20 00 00 41

SNAP I/O Module Integration Guide

BNK/

MST

CMD SCMD PRT Data

BNK/

DATA

MST

DATA

CHAPTER 3: COMMUNICATION PROTOCOLS

Here’s an example of Command 63 (Clear Serial Port Receive Buffer) sent to port 1 on the serial module at address 80:

SRC DEST CNT OSC PRC SEQ

01 80 F9 DA 20 01 00 63 72 01

BNK/

MST

DATA

CMD SCMD PRT

Another example: This time Command 53 (Group Write) is used to write to the two points on a SNAP-AOV-25 analog output module at address 8B. This command writes two 16-bit values, but only 12 bits are used for each point (see “Resolution and Range” on page 9). The command sets point 0 to 3.8 volts, which is 1556 counts in decimal, or 614 in hex. Point 1 is set to 8 volts, which is 3276 decimal counts, or 0xCCC.

SRC DEST CNT OSC PRC SEQ

01 8B F7 DA 20 04 00 53 0614 0CCC

BNK/

MST

DATA

CMD DATA

Response Message Format

# Bytes:11111110–1+

BNK/

ARCNET SRC DEST CNT OSC PRC SEQ

MST

DATA

Response Examples. The following shows the ACK response that might be received after the

sample Command 41 (Powerup Clear) is sent using the ARCNET protocol. All numbers are in hex.

SRC DEST CNT OSC PRC SEQ

85 01 FC DA 80 00 01

BNK/

MST

Here is an example of a response to a Command 52 (Group Read) reading the values of the two points on a SNAP-AIV analog input module at address 8A. The response returns four 16-bit values, but since the module has only two points, only the upper four bytes are significant.

SRC DEST CNT OSC PRC SEQ

8A 01 F4 DA 80 0A 01 09C4 3F7A 0000 0000

BNK/

MST

DATA

The data indicates that point 0 has a value in counts of 0x09C4, or 2500 decimal, which for a SNAP-AIV module equals 1 volt. (See “Resolution and Range” on page 9.) Point 1 has a value of 0x3F7A, or 16,250 decimal, which equals 6.5 volts.

SNAP I/O Module Integration Guide

GLOBAL PROTOCOL DEFINITIONS

Global Protocol Definitions

The following tables define Opto 22 product categories, message types, and error responses. These tables apply to both serial and ARCNET protocols.

Product Categories

0 - F (Hex) Reserved Numbers used by current products

10 - 1F (Hex) Brain Boards or Brains Use 10 for brain boards or brains

20 - 2F (Hex) Controllers Use 20 for controllers

30 - 3F (Hex) Hosts Use 30 for hosts

40 - 7F Future expansion --

80 and above Modules Use 80 for modules

Message Types

Type Description Byte Definition

0 Send Data Command Data [252 Bytes Max]

1 Ack Data [252 Bytes Max]

2 Nack 1-byte error Error [1 Byte] Data [251 Bytes Max]

NOTE: All binary numeric values are Little Endian (Intel) format. For example, the decimal value 35,243 would be AB 89 in hex.

Error Responses

If an error occurs, the response shows 2 in the MST or BNK/MST byte (see “Message Types” on

page 20) and the error number in the DATA byte. Error numbers are listed below.

Error

Protocol Description

(hex)

Undefined command.

Serial or ARCNET

Serial only

This error occurs when the command does not match the situation, for example, if a write command is used with an input module, or if a command 40 is sent to an older module that does not support it. See notes on commands 40 (page 32) and 41 (page 33).

DVF (checksum or CRC) error

This error code indicates a problem with the communications link, which caused a DVF error when a message from the host was sent to the I/O module. DVF errors often occur when the RS-485 network is not wired, terminated, or biased properly. Make sure of the following

1. The link is terminated at the end points and NOT in the middle.

2. The link is biased in only one location, typically at the host end.

3. Twisted-pair cable is used.

4. The link is routed in a daisy-chain fashion, NOT a “star” type distribution.

SNAP I/O Module Integration Guide

Error

Protocol Description

(hex)

Device lost power since last message

Serial or ARCNET

This error indicates that the module has reset. Configuration parameters may have been lost. This error can only be cleared by issuing a Powerup Clear command (40 or 41). See notes on commands 40 (page 32) and 41 (page 33).

CHAPTER 3: COMMUNICATION PROTOCOLS

Invalid length

This error occurs when the module receives a message that does not contain enough data characters for that command.

Invalid data—limits sent are out of range

This error indicates that at least one of the data fields in the command message contains an illegal value. Make sure that the values sent are within the range allowed by the configuration for that channel.

Serial or ARCNET

Serial or

ARCNET

Module Types, Channel Modes, and Point Types

Analog Input Modules with Four Points or Less

The following table shows module types and channel modes for SNAP analog input modules with four points or less. All numbers are shown in hex. Defaults are indicated by an asterisk (*). To change channel mode, use command 3A, Set Channel Mode (see page 31).

SNAP Module Part

Number

SNAP-AIMA

2 channels, -20 mA to +20 mA * 2 channels, 0–20 mA 2 channels, 4–20 mA

Input Range/Type Module Type

Analog Input Modules

Channel

(Hex)

64 22

Mode (Hex)

2 channels, -20 mA to +20 mA *

SNAP-AIMA-i

SNAP-AIMA-iSRC

SNAP-AIMA-4

SNAP-AIMA2-i 2 isolated channels, -1 to +1 mA 27 22

SNAP-AIMV-4

SNAP-AIMV2-4

SNAP-AITM

2 channels, 0–20 mA 2 channels, 4–20 mA

2 isolated channels, -20 mA to +20 mA * 2 channels, 0–20 mA 2 channels, 4–20 mA

4 channels, -20 mA to +20 mA * 4 channels, 0–20 mA 4 channels, 4–20 mA

4 channels, -150 mV to +150 mV * 4 channels, -75 mV to +75 mV

4 channels, -50 mV to +50 mV * 4 channels, -25 mV to +25 mV

2 channels, -150 mV to +150 mV * 2 channels, -75 mV to +75 mV

22 22

26 22

40 22

20*

SNAP I/O Module Integration Guide

MODULE TYPES, CHANNEL MODES, AND POINT TYPES

SNAP Module Part

Number

SNAP-AITM-i

SNAP-AITM-2

SNAP-AITM2-i

SNAP-AITM-4i

SNAP-AIV

SNAP-AIV-i

SNAP-AIV-4

SNAP-AIV2-i

SNAP-AIV-72 (point 0) SNAP-AIV-72 (point 1)

Input Range/Type Module Type

2 channels, -150 mV to +150 mV * 2 channels, -75 mV to +75 mV

2 channels, -50 mV to +50 mV * 2 channels, -25 mV to +25 mV

4 channels, -150 - +150 mV * 4 channels, -75 - +75 mV 4 channels, -50 - +50 mV 4 channels, -25 - +25 mV

2 channels, -10 V to +10 V * 2 channels, -5 V to +5 V

4 channels, -10 V to +10 V * 4 channels, -5 V to +5 V

2 channels, -100 to +100 VDC * 2 channels, -50 to +50 VDC

2 channels, -10 to +10 VDC 2 channels, -100 to +100 VDC

(Hex)

72 72

Channel

Mode (Hex)

20*

30 A0 B0

22*

22 22

SNAP-AIARMS 2 channels, 0 to 10 Amps RMS 71 1A

SNAP-AIARMS-i SNAP-AIARMS-i-FM

SNAP-AIVRMS 2 channels, 0 to 250 V RMS 70 1A

SNAP-AIVRMS-i SNAP-AIVRMS-i-FM

SNAP-AICTD 2 channels, Temperature (ICTD) 04 20

SNAP-AICTD-4 4 channels, Temperature (ICTD) 42 20

SNAP-AIRATE 2 channels, 0 to 25,000 Hz 69 20

SNAP-AIRATE-HFi

SNAP-AIR40K-4

SNAP-AIRTD

SNAP-AIRTD-10

2 channels, 0 to 10 Amps RMS 29 1A

2 channels, 0 to 250 V RMS 28 1A

2 channels, 0.1 s data freshness 2 channels, 1.0 s data freshness

4 channels, 0–40 K ohms * 4 channels, 0–20 K ohms 4 channels, 0–10 K ohms 4 channels, 0–5 K ohms

2 channels, 100 Ohm Pt 3-wire RTD * 2 channels, 100 Ohm Ni 3-wire RTD 2 channels, 0–400 Ohms, Lead Compensated 2 channels, 120 Ohm Ni 3-wire RTD

2 channels, 10 Ohm Cu 3-wire RTD * 2 channels, 0–25 Ohms, Lead Compensated

10 10

0E 21

44*

10*

20 30 40

SNAP-AIRTD-1K

SNAP I/O Module Integration Guide

2 channels, 1000 Ohm Pt 3-wire RTD * 2 channels, 1000 Ohm Ni 3-wire RTD 2 channels, 1–4000 Ohms, Lead Compensated

0F 21

CHAPTER 3: COMMUNICATION PROTOCOLS

SNAP Module Part

Number

SNAP-AIPM** (point 0) SNAP-AIPM (point 1) SNAP-AIPM (point 2) SNAP-AIPM (point 3)

SNAP-AILC

SNAP-AILC-2

SNAP-pH/ORP

* Default ** The SNAP-AIPM module monitors one device from point 0 (volts) and point 1 (amps). Points 2 and 3 return

calculated values. See form #1453, the SNAP AIPM Modules Data Sheet, for details.

0 to 250 V RMS 0 to 10 Amps RMS True Power Vol t-A mps

2 channels, -2 to +2 mV/V * 2 channels, -3 to +3 mV/V

2 channels, -4 to +4 mV/V * 2 channels, -3 to +3 mV/V

2 channels, –1 to +1 VDC (high impedance) * 2 channels, –0.5 to +0.5 VDC (high impedance)

Input Range/Type Module Type

(Hex)

Channel

Mode (Hex)

57 57

Don’t set

mode

8C*

20 30

Analog Input Modules with More than Four Points

The following table shows module types and point types for SNAP analog input modules with more than four points. (Channel modes are not used with these modules.)

All numbers are shown in hex. Defaults are indicated by an asterisk (*). To assign point type, use “Set

Point Configuration Command 3C” on page 31).

SNAP Module Part Number Input Range/Type Module Type

Analog Input Modules

8 channels, -20 mA to +20 mA *

SNAP-AIMA-8

SNAP-AIMA-32

SNAP-AIPM-3** (pts 0,4,8) SNAP-AIPM-3 (pts 1,5,9) SNAP-AIPM-3 (pts 2,6,10) SNAP-AIPM-3 (pts 3,7,11) SNAP-AIPM-3 (pts 12,13)

SNAP-AIPM-3V** (pts 0,4,8) SNAP-AIPM-3V (pts 1,5,9) SNAP-AIPM-3V (pts 2,6,10) SNAP-AIPM-3V (pts 3,7,11) SNAP-AIPM-3V (pts 12,13)

8 channels, 0 mA to +20 mA 8 channels, 4 mA to +20 mA

32 channels, -20 mA to +20 mA * 32 channels, 0 mA to +20 mA 32 channels, 4 mA to +20 mA

0 to 300 V RMS 0 to 5 Amps RMS True Power Volt-Am ps True Power

0 to 300 V RMS 0 to 0.333 VAC from CT True Power Volt-Am ps True Power

(Hex)

Point Type

(Hex)

40*

2 3

40*

2 3

46 47 52 53 56

64 59 5A 5A B8

SNAP I/O Module Integration Guide

MODULE TYPES, CHANNEL MODES, AND POINT TYPES

SNAP Module Part Number Input Range/Type Module Type

0 to 400K Ohms * 0 to 400K Autorange 0 to 200K Ohms 0 to 100K Ohms 0 to 50K Ohms 0 to 40K Ohms

SNAP-AIR400K-8

SNAP-AITM-8

0 to 20K Ohms 0 to 10K Ohms 0 to 5K Ohms 0 to 4K Ohms 0 to 2K Ohms 0 to 1K Ohms 0 to 500 Ohms

8 channels, -75 mV to +75 mV * 8 channels, -50 mV to +50 mV 8 channels, -25 mV to +25 mV 8 channels, type B thermocouple 8 channels, type C thermocouple 8 channels, type D thermocouple 8 channels, type E thermocouple 8 channels, type G thermocouple 8 channels, type J thermocouple 8 channels, type K thermocouple 8 channels, type N thermocouple 8 channels, type R thermocouple 8 channels, type S thermocouple 8 channels, type T thermocouple

(Hex)

Point Type

(Hex)

69 BC 6A 6B 6C 4A 4B 4C 4D

44*

9 43 18 20 21 13 1F

11 17 12

SNAP-AIV-8

SNAP-AIV-32

SNAP-AICTD-8 8 channels, Temperature (ICTD) * 4C 4*

* Default ** The SNAP-AIPM-3 and SNAP-AIPM-3V modules monitor three phases from points 0, 4, and 8 (volts)

and points 1, 5, and 9 (amps). All other points return calculated values. See form #1453, the SNAP AIPM Modules Data Sheet, for details.

8 channels, -10 V to +10 V * 8 channels, -5 V to +5 V

32 channels, -10 V to +10 V * 32 channels, -5 V to +5 V

SNAP I/O Module Integration Guide

CHAPTER 3: COMMUNICATION PROTOCOLS

Analog Output, Serial, and High-Density Digital Modules

The following table shows module types for analog output modules, serial modules, and high-density digital modules. Module types are shown in hex. (Neither channel modes nor point types are used with these modules.)

Module Description Module Type

Analog Output Modules

SNAP-AOA-3 1 channel, 4–20 mA 83

SNAP-AOV-5 1 channel, 0–10 VDC 85

SNAP-AOA-23 2 channels, current loop 4–20 mA A3

SNAP-AOA-23-iSRC 2 isolated channels, current loop 4–20 mA B3

SNAP-AOV-25 2 channels, 0–10 VDC A5

SNAP-AOV-27 2 channels, -10 to +10 VDC A7

SNAP-AOA-28 2 channels, current loop 0–20 mA A8

SNAP-AOD-29 2 channels, time-proportional digital output 5–60 VDCA9

Serial Modules

SNAP-SCM-232 2 channels, RS-232 F0

SNAP-SCM-485-422 2 channels, RS-485/422 (2-wire or 4-wire) F1

SNAP-SCM-PROFI One electrical interface to PROFIBUS DP® networks.F6

High-Density Digital Modules

SNAP-IDC-32 SNAP-IDC-32-FM

32 channels, digital inputs, 10–32 VDC E0

(Hex)

SNAP-IDC-32N 32 channels, digital inputs, -10 to -32 VDC E6

SNAP-IDC-32D 32 channels, digital inputs, 2.5 to 12 VDC EB

SNAP-IDC-32DN 32 channels, digital inputs, -2.5 to -12 VDC EA

SNAP-IDC-16 16 isolated channels, digital inputs, 10–32 VDC/VAC E5

SNAP-IDC-HT-16 16 isolated channels, digital inputs, 15–28 VDC/VAC E8

SNAP-IAC-16 16 isolated channels, digital inputs, 90–140 VAC/VDC E4

SNAP-IAC-A-16 16 isolated channels, digital inputs, 180–280 VAC/VDC E3

SNAP-IAC-K-16 16 isolated channels, digital inputs, 70–130 VAC/VDC E7

SNAP-ODC-32-SRC SNAP-ODC-32-SRC-FM

SNAP-ODC-32-SNK SNAP-ODC-32-SNK-FM

32 channels, digital outputs, 5–60 VDC load sourcing E1

32 channels, digital outputs, 5–60 VDC load sinking E2

SNAP I/O Module Integration Guide

MODULE TYPES, CHANNEL MODES, AND POINT TYPES

SNAP I/O Module Integration Guide

Chapter 5

4: Commands

Introduction

This chapter starts with a list of all commands and then details individual commands.

In this chapter, only the data required for each command is illustrated. For complete packet information and examples, see “Serial Protocol Details” on page 13 or “ARCNET Protocol Details” on

page 18.

CAUTION: Notice that some commands have the same command number but apply to different types of modules. For example, command 52 takes a different action depending upon what type of module (analog input, TPO, high-density digital, or serial module) it is sent to. Make sure you address modules carefully, so that commands will have the effect you intend.

IMPORTANT: The commands in this chapter support the following serial communication modules only:

• SNAP-SCM-232 Revision A modules (manufactured in June 2003 or after) with firmware R1.1e or higher. These modules support optional RTS/CTS flow control.

• SNAP-SCM-232 modules manufactured before June 2003 with firmware R1.1o. These modules do not support RTS/CTS flow control.

• SNAP-SCM-485-422 modules. (Modules manufactured before June 2003 with the part number SNAP-SCM-485 do not work with the commands in this guide.)

SNAP I/O Module Integration Guide 27

COMMAND LIST

Command List

Commands are shown in numerical order, in hex. Some commands have the same number; be sure to choose the one that applies to your module.

Applies to Modules

Hex Serial ARCNET Command

HDD*

Analog

23 X Read Number of Received Data Bytes Waiting X page 30

32 X X Read Channel Mode (Input modules only) X X page 30

3A X X Set Channel Mode (Input modules only) X X page 31

3C X X Set Point Configuration X page 31

40 X X Powerup Clear—Current Modules (Enables watchdog timer) X X X X page 32

41 X X Powerup Clear—Legacy Modules (Disables watchdog timer) X X X X page 33

42 X X Reset X X page 33

42 X Read Amount of Unused Space in Transmit Buffer X page 34

45 X X Save Current Module Configuration in EEPROM (Input modules only) X X page 34

46 X X Identify Module Type X X X X page 35

47 X Set Serial Port Configuration X X X X page 35

48 X Set Serial Port Response Delay X X X X page 36

49 X X Read Module Firmware Revision X X X page 36

52 X Group Read X page 37

52 X X Group Read (Input and SNAP-AOD-29 modules only) X page 37

>4 ch

Analog

=<4-ch

See

Serial**

52 X Read Status—Latches Not Cleared X page 38

52 X Receive Serial Data Only X page 38

53 X X Group Write (Dual-channel output modules only) X page 39

53 X Read Status—Latches Cleared (Input modules only) X page 39

54 X X Read HDD Counters—Counters Not Cleared X page 40

55 X X Read HDD Counters—Counters Cleared X page 40

55 X X Channel Read X page 41

56 X X Channel Write (Output and SNAP-AOD-29 modules only) X page 41

57 X X Set TPO Period (SNAP-AOD-29 modules only) X page 42

58 X Write Outputs X page 42

58 X X Read Status (TPO, Inhibit On/Off) (SNAP-AOD-29 modules only) X page 43

63 X Clear Serial Port Receive Buffer X page 43

66 X Read Serial Port CTS (SCM-232 Rev A modules only) X page 44

66 X Set Serial Port RTS (SCM-232 Rev A modules only) X page 44

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Applies to Modules

Hex Serial ARCNET Command

HDD*

=<4-ch

Analog

>4 ch

Analog

66 X Clear Serial Port RTS (SCM-232 Rev A modules only) X page 45

69 X

71 X Read Serial Port Configuration X page 46

71 X Write Serial Port Configuration X page 47

71 X Write Serial Port Configuration and Store to Flash X page 48

72 X Receive Line of Serial Data X page 48

73 X Send & Receive Serial Data X page 49

74 X Send Serial Data X page 49

*HDD = high-density digital **SNAP-SCM-232 and SNAP-SCM-485-422 modules only

Read Serial Module Info (SCM-232 Rev A, SCM-485-422 modules only)

See

Serial**

X page 45

SNAP I/O Module Integration Guide

COMMAND DETAILS

Command Details

Read Number of Received Data Bytes Waiting Command 23

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command reads the quantity of bytes waiting in the serial port’s receive buffer.

Command Data Required

CMD 1 byte 23

PRT 1 byte Serial port: 00 for port 0, 01 for port 1

Response Data Received

Data 2 bytes

Number of bytes of received data in the specified serial port’s receive buffer (2-byte value in Big Endian format—most significant byte at lowest memory address)

Read Channel Mode Command 32

(Analog input modules with four points or less)

For analog input modules with 4 points or less, this command reads the current input channel (point) mode. For possible channel modes, see “Module Types, Channel Modes, and Point Types” on

page 21.

To set channel mode, see command 3A on page 31

Command Data Required

CMD 1 byte 32

Data 1 byte Channel (point) number

Response Data Received

Data 1 byte

Channel mode value for specified point (See “Module Types, Channel Modes, and Point

Types” on page 21.)

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Set Channel Mode Command 3A

(Analog input modules with 4 points or less)

For analog inputs for 4 points or less, this command sets the channel (point) mode. For possible modes, see “Module Types, Channel Modes, and Point Types” on page 21.

To save this information to EEPROM, use command 45.

For analog input modules with more than 4 channels, see “Set Point Configuration Command 3C,” below.

Command Data Required

CMD 1 byte 3A

MSB LSB

1 byte 1 byte

Data

Response Data Received

No response data

Channel (point) number Channel mode value

Set Point Configuration Command 3C

(Analog input modules with more than four points)

For analog inputs with more than 4 points, this command configures the specified point. For possible configurations, see “Analog Input Modules with More than Four Points” on page 23.

If the point configuration data sent with the command is not valid, the default configuration for the module is used. Non-existing channels are ignored.

For a similar command to use with 4-channel analog input modules, see “Set Channel Mode

Command 3A,” above.

Command Data Required

CMD 1 byte 3C

MSB LSB

1 byte 1 byte

Data

Response Data Received

No response data

Channel (point) number Point configuration (see page 23)

SNAP I/O Module Integration Guide

COMMAND DETAILS

Powerup Clear—Current Modules Command 40

This initialization command is used to acknowledge that the modules has powered up since the last time the brain communicated with it. This command also enables the command watchdog timer on the module (see notes, below). The command watchdog timer monitors commands received via Arcnet for that module address; if a command is received by the module via Arcnet at least once every 6 seconds, the module will function as normal. However, if the module does not receive a command via Arcnet within a 6 second period, it will assume there is a problem with Arcnet communication, and it initiate an Arcnet bus reconfiguration.

This command must be sent before any other commands will be recognized. This command clears the “Powerup Clear expected” error flag.

Notes: Normal Arcnet command/response times are on the order of milliseconds, so 6 seconds without any Arcnet communication would indicate an abnormal condition.

The command watchdog timer is available on most SNAP I/O modules manufactured after 2004. It is strongly recommended that you use command 40 with modules that support the command watchdog timer. For example, you can initially send command 40 and see if you get a valid response. If you do, then you know that module supports the command watchdog feature. However, you will receive a NAK response if the module does not support this feature. In that case, use command 41 instead.

Command Data Required

CMD 1 byte 40

Response Data Received

No response data

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Powerup Clear—Legacy Modules Command 41

This initialization command is used to acknowledge that the modules has powered up since the last time the brain communicated with it. This command also disables the command watchdog timer on the module. It should be used only for legacy modules; for newer modules that contain a watchdog, we strongly recommend that you enable the command watchdog feature by using command 40 instead.

A Powerup Clear must be sent before any other commands will be recognized. This command clears the “Powerup Clear expected” error flag. If used on a module with a watchdog timer, it disables the timer.

Note: See notes on command 40 for information about the command watchdog feature.

Command Data Required

CMD 1 byte 41

Response Data Received

No response data

Reset Command 42

(Analog input and output modules only)

This command causes a soft reset of the module’s microprocessor.

Like the automatic reset upon powerup, this Reset command must be followed by a Powerup Clear command (41) to restore normal operation.

Command Data Required

CMD 1 byte 42

Response Data Received

No response data

SNAP I/O Module Integration Guide

COMMAND DETAILS

Read Amount of Unused Space in Transmit Buffer Command 42

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command reads the number of bytes of available space in the specified serial port’s transmit buffer. This command can be used to prevent overrun of the buffer.

Command Data Required

CMD 1 byte 42

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Response Data Received

Data 4 bytes

Number of bytes that can be added to the serial port’s transmit buffer without overrunning it (4-byte value in Big Endian format—most significant byte at lowest memory address)

Save Current Module Configuration in EEPROM Command 45

(Analog input modules only)

This command saves channel mode (set with command 3A) and serial port settings (command 47) to EEPROM. Settings are then used automatically upon powerup or reset.

Command Data Required

CMD 1 byte 45

Response Data Received

No response data

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Identify Module Type Command 46

This command reads a 2-byte identification number. The upper byte identifies the product as a module; the lower byte indicates the module type. For more information, see “Module Types,

Channel Modes, and Point Types” on page 21.

Command Data Required

CMD 1 byte 46

Response Data Received

MSB

Data

LSB

1 byte 1 byte

80 = module Module type. See “Module Types, Channel Modes, and Point Types” on page 21.

Set Serial Port Configuration Command 47

Serial protocol only.

This command sets or resets the module’s serial port parameters for communication using the serial protocol. See “Serial Communication” on page 13.

Command Data Required

CMD 1 byte 47

Data 1 byte Serial port configuration. See “Serial Communication” on page 13.

Response Data Received

No response data

SNAP I/O Module Integration Guide

COMMAND DETAILS

Set Serial Port Response Delay Command 48

Serial protocol only.

This command sets a time delay after command execution before a response or ack is returned. This feature may be useful when switching times of modems or if protocol delays need a dead time between serial transmissions.

Command Data Required

CMD 1 byte 48

Data 1 byte Delay byte in hex (Delay = delay byte * 10 milliseconds)

Response Data Received

No response data

Read Module Firmware Version Command 49

(All modules except SNAP-SCM-232 and SNAP-SCM-485-422)

This command is used for troubleshooting, usually with the help of Opto 22 Product Support; it reads the version number of the module’s firmware.

Command Data Required

CMD 1 byte 49

Response Data Received

Data 2 bytes Firmware version number

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Group Read Command 52

(Analog modules with more than four points)

ARCNET protocol only.

For analog modules with more than four channels, this command returns two 16-bit values, corresponding to points 0–31 on the module. The first 16-bit value, “field terminal counts,” applies to all these modules. The second 16-bit value, “cold junction counts,” applies only to modules used as thermocouples; ignore these bytes for other modules. The data is unmodified from the ADC (analog-to-digital converter—sign plus 15 bits).

Command Data Required

CMD 1 byte 52

Response Data Received

Point 0 field terminal counts Point 0 cold junction counts (thermocouples only) Point 1 field terminal counts Point 1 cold junction counts (thermocouples only)

Point 31 field terminal counts Point 31 cold junction counts (thermocouples only) (Total of 128 bytes for 32 points)

Data

MSB

LSB

2 bytes 2 bytes 2 bytes 2 bytes

2 bytes 2 bytes

Group Read Command 52

(Analog 4-channel input and SNAP-AOD-29 TPO modules only)

For analog input modules, this command returns four 16-bit values, corresponding to points 0–3 on the module. The data is unmodified from the ADC (analog-to-digital converter); however, offset and gain modifications are applied.

For the TPO module, this command returns the TPO and period for both channels.

Command Data Required

CMD 1 byte 52

Response Data Received

Point 0 data (or TPO percent for point 0) Point 1 data (or TPO period for point 0) Point 2 data (or TPO percent for point 1) Point 3 data (or TPO period for point 1)

Data

MSB

LSB

2 bytes 2 bytes 2 bytes 2 bytes

SNAP I/O Module Integration Guide

COMMAND DETAILS

Read Status—Latches Not Cleared Command 52

(High-density digital input modules only)

ARCNET protocol only.

For high-density digital input modules, this command reads status, on latches, and off latches for all points. Latches remain as read; they are not cleared. The command returns four 32-bit values, each corresponding to points 0–31 on the module.

To read and clear latches, see “Read Status—Latches Cleared Command 53” on page 39.

Command Data Required

CMD 1 byte 52

Response Data Received

Status of all points (1 = On; 0 = Off) On-latches set (1 = latch set; 0 = latch clear) Off-latches set (1 = latch set; 0 = latch clear) (Future use)

Data

MSB

LSB

4 bytes 4 bytes 4 bytes 4 bytes

Receive Serial Data Command 52

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command receives up to the number of serial bytes specified on the specified port, to a maximum of 249. This command does not look for an end-of-line (EOL) character. To receive a line of serial data, see Command 72 (page 48).

Command Data Required

CMD 1 byte 52

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Data 1 byte Number of bytes to be received (cannot be more than 249)

Response Data Received

Data

0 249

bytes

SNAP I/O Module Integration Guide

Serial data from specified port’s receive buffer. Up to 249 received data bytes can be included in the response.

CHAPTER 4: COMMANDS

Group Write Command 53

(Dual-channel analog output modules only)

This command writes two 16-bit values (12 bits used) to point 0 and point 1 of a dual-channel output module. For examples of how to write data, see “Serial Message Examples” on page 15 or

“ARCNET Message Examples” on page 18.

Sending this command to a single-channel output module results in an undefined command error (error 01; see “Error Responses” on page 20).

Command Data Required

CMD 1 byte 53

MSB

LSB

2 bytes 2 bytes

Data

Response Data Received

No response data

Data to write to point 0 Data to write to point 1

Read Status—Latches Cleared Command 53

(High-density digital input modules only)

ARCNET protocol only.

For high-density digital input modules, this command reads status, on latches, and off latches for all points, and it clears all latches after reading. The command returns four 32-bit values, each corresponding to points 0–31 on the module.

To read without clearing latches, see “Read Status—Latches Not Cleared Command 52” on page 38.

Command Data Required

CMD 1 byte 53

Response Data Received

Status of all points (1 = On; 0 = Off) On-latches set (1 = latch set; 0 = latch clear) Off-latches set (1 = latch set; 0 = latch clear) (Future use)

Data

MSB

LSB

4 bytes 4 bytes 4 bytes 4 bytes

SNAP I/O Module Integration Guide

COMMAND DETAILS

Read HDD Counters—Counters Not Cleared Command 54

(High-density digital modules only)

For high-density digital (HDD) modules, this command reads counters for all points on the module but does not clear counters. The command returns two 16-bit values, corresponding to points 31–0 on the module.

To read and clear counters at the same time, see “Read HDD Counters—Counters Cleared

Command 55,” below.

Command Data Required

CMD 1 byte 54

Response Data Received

Point 31 counter Point 30 counter

Point 0 counter

Data

MSB

LSB

2 bytes 2 bytes

2 bytes

Read HDD Counters—Counters Cleared Command 55

(High-density digital modules only)

For high-density digital (HDD) modules, this command reads and clears counters for all points on the module. The command returns two 16-bit values, corresponding to points 31–0 on the module.

To read counters without clearing them, see “Read HDD Counters—Counters Not Cleared

Command 54,” above.

Command Data Required

CMD 1 byte 55

Response Data Received

etc.

Point 31 counter Point 30 counter Point 29 counter Point 28 counter etc. to Point 0

Data

2 bytes 2 bytes 2 bytes 2 bytes

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

OnTime

OutputData

4095

-------------------------------





Period=

Output Data 4095

DesiredOnTime

Period

------------------------------------------





=

Channel Read Command 55

(Analog modules with more than four points)

For analog modules with more than four points, this command returns two 16-bit values for the specified point on the module. The data is unmodified from the ADC (analog-to-digital converter— sign plus 15 bits); however, offset and gain modifications are applied.

Command Data Required

CMD 1 byte 55

Data 1 byte Point number (00 to 03 hex)

Response Data Received

Data

2 bytes 2 bytes

Field terminal counts for specified point Cold junction counts for specified point

Channel Write Command 56

(Analog output and SNAP-AOD-29 TPO modules only)

On an analog output module, this command writes a 16-bit value (12 bits used) to the specified output channel (point) on the module.

On a TPO module, this command writes the TPO “on” time (duty cycle) for the period.

Note: On Time and Period are both in units of seconds.

To set the period, use command 57.

Command Data Required

CMD 1 byte 56

1 byte

Data

2 bytes

Response Data Received

No response data

Point number (00 or 01) Output data for point

SNAP I/O Module Integration Guide

COMMAND DETAILS

Value

Period

0.251

-----------------





1–=

Set TPO Period Command 57

(SNAP-AOD-29 TPO modules only)

This command sets the time-proportional output (TPO) period for a single channel (point) on a SNAP-AOD-29 output module. Use command 56 to set the TPO “on” time.

Command Data Required

CMD 1 byte 57

1 byte

Data

2 bytes

Determine the value to set the period as shown below. “Period” in the equation is the desired period in units of seconds.

Valid limits: period of 0.251 seconds at 0; 16,449.536 seconds at 65,535.

Response Data Received

Point number (00 or 01) Value to set the period. See equation below.

No response data

Write Outputs Command 58

(High-density digital output modules only)

ARCNET protocol only.

For high-density digital output modules, this command writes status to all 32 output points on the module at once. The command uses two masks: one determines which points to write to, and the other determines whether to write “on” or “off.”

NOTE: Sending this command to a 32-channel input module will result in an undefined command error.

Command Data Required

CMD 1 byte 58

4 bytes

Data

4 bytes 4 bytes

Response Data Received

Set output points (1 = On; 0 = Off) Points to write to (1 = ignore point; 0 = write to point) Future use

SNAP I/O Module Integration Guide

No response data

CHAPTER 4: COMMANDS

0 TPO 0 LED 1; 1 = Output On

1 TPO 1 LED 2; 1 = Output On

2 Inhibit 0 LED 3; 1 = Inhibit

3 Inhibit 1 LED 4; 1 = Inhibit

4 TPO 0 Status before its inhibit; 1 = Output On

5 TPO 1 Status before its inhibit; 1 = Output On

6–7 Reserved

Read Status (TPO, Inhibit On/off) Command 58

(SNAP-AOD-29 TPO modules only)

This command reads an 8-bit value from the SNAP-AOD-29 TPO module. The 8-bit value contains the output status, the inhibit status, and the output status just prior to inhibit. Only the first six bits are used. See table below.

Command Data Required

CMD 1 byte 58

Response Data Received

TPO status. Bit functions are:

Data 1 byte

Clear Serial Port Receive Buffer Command 63

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only) Subcommand 72

ARCNET protocol only.

This command clears any received data from the specified serial port’s receive buffer.

Command Data Required

CMD 1 byte 63

SCMD 1 byte 72

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Response Data Received

No response data

SNAP I/O Module Integration Guide

COMMAND DETAILS

Read Serial Port CTS Command 66

(SNAP-SCM-232 Rev A modules only) Subcommand 72-63

ARCNET protocol only.

This command reads the state of the CTS signal for the specified serial port.

NOTE: If this command is used on a serial module with hardware prior to Rev A, an undefined command error is returned. (Older hardware does not support RTS/CTS.)

Command Data Required

CMD 1 byte 66

SCMD

Response Data Received

1 byte 1 byte7263

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Data 1 byte CTS: 01 = asserted; 00 = deasserted

Set Serial Port RTS Command 66

(SNAP-SCM-232 Rev A modules only) Subcommand 73-72

ARCNET protocol only.

This command sets (asserts) the RTS signal for the specified serial port. This command has no effect on RTS if the serial port is configured for hardware flow control.

Command Data Required

CMD 1 byte 66

SCMD

Response Data Received

No response data

1 byte 1 byte7372

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Clear Serial Port RTS Command 66

(SNAP-SCM-232 Rev A modules only) Subcommand 63-72

ARCNET protocol only.

This command clears (deasserts) the RTS signal for the specified serial port. This command has no affect on RTS if the serial port is configured for hardware flow control.

Command Data Required

CMD 1 byte 66

SCMD

Response Data Received

No response data

1 byte 1 byte6372

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Read Serial Module Info Command 69

(SNAP-SCM-232 Rev A and SNAP-SCM-485-422 modules only) Subcommand 72

ARCNET protocol only.

This command reads module type and hardware and firmware versions.

NOTE: If this command is used on a serial module with older hardware (SNAP-SCM-232 prior to Rev A or SNAP-SCM-485), an undefined command error is returned.

Command Data Required

CMD 1 byte 69

SCMD 1 byte 72

Response Data Received

1 byte

1 byte 4 bytes 4 bytes

Data

4 bytes

Module type; see page 25. Module subtype = 01 for Revision A Hardware revision date. Format is DDMMYYYY in hex (1B0A07D4 = 27 October 2004) Loader version number in the format MMmmTTbb (in hex), where:

MM = Major version mm = Minor version TT = Type (00 = alpha; 01 = beta; 02 = release) bb = Build number (00–FF) Example: 0103020E = R1.3o

Firmware version number in same format as loader revision

SNAP I/O Module Integration Guide

COMMAND DETAILS

Read Serial Port Configuration Command 71

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only) Subcommand 67

ARCNET protocol only.

This command reads the port configuration for all serial ports on the module.

Command Data Required

CMD 1 byte 71

SCMD 1 byte 67

Response Data Received

Data

(total

bytes)

4 bytes

1 byte 1 byte 1 byte 1 byte 1 byte

4 bytes

1 byte 1 byte 1 byte 1 byte 1 byte

5 bytes

1 byte

10 bytes

5 bytes

1 byte

10 bytes

1 byte

Port 0: Data rate, bps (32-bit integer in Big Endian format) Port 0: Parity. N = none, O = odd, E = even, M = mark, S = space Port 0: Number of data bits (5–8) Port 0: Stop bits (1, 2) Port 0: Handshake. 0 = none, 1 = hardware (RTS/CTS full duplex flow control) Port 0: Port greeting enabled on powerup. 1 = yes, 0 = no Port 1: Data rate, bps (32-bit integer in Big Endian format) Port 1: Parity. N = none, O = odd, E = even, M = mark, S = space Port 1: Number of data bits (5–8) Port 1: Stop bits (1, 2) Port 1: Handshake. 0 = none, 1 = hardware (RTS/CTS full duplex flow control) Port 1: Port greeting enabled on powerup. 1 = yes, 0 = no Port 0: End-of-line terminating character list. Contains a null-terminated string of up to 4 EOL terminating characters. Port 0: Filter out sequential duplicate lines. 1 = yes, 0 = no Port 0: Reserved Port 1: End-of-line terminating character list. Contains a null-terminated string of up to 4 EOL terminating characters. Port 1: Filter out sequential duplicate lines. 1 = yes, 0 = no Port 1: Reserved Mode. 0 = 2-wire, 1 = 4-wire (SCM-485-422 modules only)

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Write Serial Port Configuration Command 71

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only) Subcommand 6E

ARCNET protocol only.

This command writes port configuration to all serial ports on the module. Configuration is not stored to flash; to write the configuration and store it to flash, use command 71 with subcommand 73 (page 48).

Command Data Required

CMD 1 byte 71

SCMD 1 byte 6E

Data (total

bytes)

4 bytes

1 byte

1 byte 4 bytes

1 byte

1 byte 5 bytes

1 byte

10 bytes

5 bytes

1 byte

10 bytes

1 byte

Response Data Received

No response data

SNAP I/O Module Integration Guide

COMMAND DETAILS

Write Serial Port Configuration and Store to Flash Command 71

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only) Subcommand 73

ARCNET protocol only.

This command writes port configuration to all serial ports on the module and stores configuration to flash. If you don’t want to store to flash, use command 71 with subcommand 6E (page 47).

Command Data Required

CMD 1 byte 71

SCMD 1 byte 73

Data 51 bytes Same details as command 71, subcommand 6E (see page 47)

Response Data Received

No response data

Receive Line of Serial Data Command 72

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command receives one line of data (or 249 bytes, whichever is shorter) from the specified serial port. A line ends when one of the configured end-of-line (EOL) terminating characters for the serial port appears.

If an EOL character is found in data received by the serial port, all data bytes up to the EOL character are returned in the response. The EOL character itself is thrown away. This command cannot return more than 249 bytes of received data. If an EOL character is not detected within 249 bytes, the first 249 bytes received are returned. If there are less than 249 bytes and no EOL, the response comes back immediately with no characters. (To retrieve data in this situation, use Command 52, Receive Serial Data.)

Command Data Required

CMD 1 byte 72

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

Response Data Received

Data

0 to 249

bytes

One line of data from the serial port’s receive buffer, ending at EOL character or at 249 bytes, whichever is shorter

SNAP I/O Module Integration Guide

CHAPTER 4: COMMANDS

Send & Receive Serial Data Command 73

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command transmits up to 247 data bytes out the specified serial port and immediately returns any data in the serial port’s receive buffer in response. This command is the same as using command 74, Send Serial Data Only (page 49) followed by command 52, Receive Serial Data Only (page 38), but it is more efficient since it requires only one command/response transaction.

Command Data Required

CMD 1 byte 73

PRT 1 byte Serial port number: 00 for port 0; 01 for port 1

0 to 247

Data

bytes

Response Data Received

Data to transmit out serial port. Maximum 247 bytes.

Data

1 byte to

249 bytes

Serial data from specified port’s receive buffer. Up to 249 received data bytes can be included in the response.

Send Serial Data Command 74

(SNAP-SCM-232 and SNAP-SCM-485-422 modules only)

ARCNET protocol only.

This command transmits up to 247 data bytes out the specified serial port.

To transmit and receive in the same command, use command 73, Send & Receive Serial Data.

Command Data Required

CMD 1 byte 74

PRT 1 byte Serial port: 00 for port 0, 01 for port 1

1 byte to

Data

247 bytes

Response Data Received

Data to transmit out serial port. Maximum 247 bytes.

No response data

SNAP I/O Module Integration Guide

COMMAND DETAILS

SNAP I/O Module Integration Guide

Index

addressing modules

ARCNET protocol serial protocol, 11

analog module

channel mode configuring points, 31 description, 1 electrical specifications, 8 input module types, 21, 23 mechanical specifications, 5 output module types, 25 reading, 41 reading points, 37 resolution, 9 scaling, 9 wiring, 8 writing to output, 39, 41

ARCNET protocol, 17

communication, 17 message examples, 18 message field definitions, 18

ASCII, 13, 14

message format, 16 response format, 16

, 17

, 21, 23

baud rate, 13 binary, 13

format of numeric values, 20 message format, 15 response format, 16

BNK/MST, 20

categories for products, 20

channel mode, 21, 23

reading, 30

setting, 31 channel numbering, 12, 17 Channel Read, 41 Channel Write, 41 checksum, 13, 14

calculating, 14, 15

error, 20 Clear Serial Port Receive Buffer, 43 Clear Serial Port RTS, 45 command

list of all commands

message format (ARCNET protocol), 18

message format (serial protocol), 15 communication

ARCNET protocol

default serial port settings, 13

serial protocol, 11

with modules, 2 configuring

point type configuring point type, 23 counters, 40

clearing, 40 CRC16, 13, 14, 15 CTS

modules supported

reading, 44

, 31

, 28

, 17

, 9

data sheets for modules, 2 data verification, 13

serial protocol, 14 digital module

description

electrical specifications, 7

mechanical specifications, 5

, 1

SNAP I/O Module Integration Guide 51

reading & clearing HDD counters, 40 reading & clearning HDD latches, 39 reading HDD counters, 40 reading HDD latches, 38

wiring, 7 disabling watchdog timer, 33 duty cycle, 41 DVF, 14

calculation example, 15

error, 20

high scale, 9 high-density digital module

description module type, 25 reading & clearing counters, 40 reading & clearing latches, 39 reading counters, 40 reading latches, 38 reading status, 38, 39 writing outputs, 42

, 1

EEPROM, saving to, 34, 48 electrical specifications, 7 enabling watchdog timer, 32, 33 error numbers, 20 error responses, 20 example

ARCNET protocol message

reading input (ARCNET protocol), 19

reading input (serial protocol), 16

serial protocol message, 15

writing to output (ARCNET protocol), 19

writing to output (serial protocol), 15

, 18

field definitions

ARCNET protocol

serial protocol, 14 firmware, reading version, 36, 45 flash memory

saving to

storing serial module configuration, 48 format

ARCNET protocol message

binary numeric values, 20

serial protocol message, 15

, 18

, 34

, 18

Group Read, 37 Group Write, 39

hardware

reading version

serial modules supported, 9 help

Product Support

, 45

, 3

Identify Module Type, 35 inhibit status (TPO), 43 input

reading values, ARCNET protocol example reading values, serial protocol example, 16

interface

electrical mechanical, 5

, 7

latches, 38, 39 Linux brain, 2, 17 list of commands, 28 low scale, 9

mechanical specifications, 5 message field definitions

ARCNET protocol serial protocol, 14

message types, 20 module

addressing for ARCNET protocol addressing for serial protocol, 11 choosing modules, 2 communicating with, 2 mounting rack, 5 power requirements, 10 types, 1, 21

, 18

, 17

identifying, 35

mounting rack, 5 MST, 20

Opto 22 Product Support, 3

, 19

SNAP I/O Module Integration Guide

output

writing values to, ARCNET protocol example writing values to, serial protocol example, 15

over range, 9

, 19

packet

ARCNET protocol serial protocol, 14

point

configuring numbering, 12, 17

types, 23 port settings for serial protocol, 13 power requirements for modules, 10 Powerup Clear, 32, 33 PRC, 20 product categories, 20 Product Support, 3 protocol

ARCNET

, 17

choosing, 2

serial, 11

, 18

, 23

rack, 5 range, 9 Read Amount of Unused Space in Transmit Buffer,

Read and Clear HDD Counters, 40 Read Channel Mode, 30 Read HDD Counters, 40 Read Module Firmware Version, 36 Read Number of Received Data Bytes Waiting, 30 Read Serial Module Info, 45 Read Serial Port Configuration, 46 Read Serial Port CTS, 44 Read Status (TPO, Inhibit On/Off), 43 Read Status—Latches Cleared, 39 Read Status—Latches not Cleared, 38 reading analog input points, 16, 19, 37, 41 Receive Line of Serial Data, 48 Receive Serial Data, 38 Reset, 33 resolution, 9 response

errors

, 20

message format (ARCNET protocol), 19

message format (serial protocol), 16

RTS, 45

modules supported, 9 setting, 44

Save Current Module Configuration in EEPROM, 34 scaling, 9 Send & Receive Serial Data, 49 Send Serial Data, 49 serial communication module

buffer overrun clearing receive buffer, 43 clearing RTS, 45 description, 1 module types, 25 modules supported, 9 reading bytes waiting, 30 reading configuration, 46 reading CTS, 44 reading hardware and firmware version, 45 receiving data, 38, 48, 49 sending data, 49 setting RTS, 44 writing configuration, 47, 48

serial module

mechanical specifications module types, 25

serial protocol, 11

ASCII, 13 ASCII examples, 16 binary, 13 binary examples, 15, 16 communication settings, 13 data verification, 14 message examples, 15 message field definitions, 14

setting port configuration, 35, 36 Set Channel Mode, 31 Set Point Configuration, 31 Set Serial Port Configuration, 35 Set Serial Port Response Delay, 36 Set Serial Port RTS, 44 Set TPO Period, 42 SNAP-ARL-ASDS brain, 17 SNAP-SCM-232 serial module, 9 SNAP-SCM-485 serial module, 9 SNAP-SCM-485-422 serial module, 9 specifications

electrical

mechanical, 5

module data sheets, 2

power requirements, 10

, 34

, 5

, 7

SNAP I/O Module Integration Guide 53

technical support, 3 TPO, 37, 41, 42, 43 troubleshooting

error responses Product Support, 3

types of messages, 20

, 20

under range, 9

watchdog timer

disabling

enabling, 32 watchdog timer, enabling, 33 wiring, 7

module addresses for serial protocol, 12 Write Outputs, 42 Write Serial Port Configuration, 47 Write Serial Port Configuration and Store to Flash, 48 writing to analog output, 39, 41

, 33

SNAP I/O Module Integration Guide

OPTO 22 SNAP Integration Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1: Introduction

SNAP I/O Modules

Choosing SNAP I/O Modules

Communicating with SNAP I/O Modules

About this Guide

For Help

2: Interfaces

Mechanical Interface

All Modules

Using Modules with an Opto 22 Mounting Rack

Using Modules without an Opto 22 Mounting Rack

Electrical Interface

4-Channel Digital Input/Output Modules

Analog Modules

Other Modules

SNAP Module Power Requirements

3: Communication Protocols

Introduction

Serial Protocol (Binary or ASCII)

Addressing

Serial Communication

Serial Protocol Details

About Data Verification

Serial Message Examples

ARCNET Protocol

Addressing

Communication

ARCNET Protocol Details

ARCNET Message Examples

GLOBAL PROTOCOL DEFINITIONS

Product Categories

Message Types

Error Responses

Module Types, Channel Modes, and Point Types

Analog Input Modules with Four Points or Less

Analog Input Modules with More than Four Points

Analog Output, Serial, and High-Density Digital Modules

4: Commands

Introduction

COMMAND LIST

COMMAND DETAILS

Read Number of Received Data Bytes Waiting Command 23

Read Channel Mode Command 32

Set Channel Mode Command 3A

Set Point Configuration Command 3C

Powerup Clear—Current Modules Command 40

Powerup Clear—Legacy Modules Command 41

Reset Command 42

Read Amount of Unused Space in Transmit Buffer Command 42

Save Current Module Configuration in EEPROM Command 45

Identify Module Type Command 46

Set Serial Port Configuration Command 47

Set Serial Port Response Delay Command 48

Read Module Firmware Version Command 49

Group Read Command 52

Group Read Command 52

Read Status—Latches Not Cleared Command 52

Receive Serial Data Command 52

Group Write Command 53

Read Status—Latches Cleared Command 53

Read HDD Counters—Counters Not Cleared Command 54

Read HDD Counters—Counters Cleared Command 55

Channel Read Command 55

Channel Write Command 56

Set TPO Period Command 57

Write Outputs Command 58

Read Status (TPO, Inhibit On/off) Command 58

Clear Serial Port Receive Buffer Command 63

Read Serial Port CTS Command 66

Set Serial Port RTS Command 66

Clear Serial Port RTS Command 66

Read Serial Module Info Command 69

Read Serial Port Configuration Command 71

Write Serial Port Configuration Command 71

Write Serial Port Configuration and Store to Flash Command 71

Receive Line of Serial Data Command 72