Yokogawa M Series User Manual

User’s Manual

M Series Digital Limit Alarms Communication Functions

IM 77J04J11-01E

1st Edition

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Introduction

This user's manual describes the communication functions of the M Series digital limit alarms (hereinafter simply referred to as M Series) and contains information on how to create communication programs.

Read the manual carefully to understand the communication functions of the M Series.

The M Series have the following communication protocols.

● PC link communication protocol

● MODBUS communication protocol

● Ladder communication protocol

Note that the M Series cannot communicate with a higher-level device with a communication protocol other than these.

You are required to have background knowledge of the communication specifications of higher-level devices, their communication hardware, language used for creating communication programs, and so on.

■ Intended Readers

This manual is intended for people familiar with the functions of the M Series, control engineers and personnel in charge of maintaining instrumentation and control equipment.

■ Related Documents

The following user's manuals all relate to the communication functions of the M Series. Read them as necessary.

● Model MVHK Digital Limit Alarm (DC Input Type) Document number: IM 77J04H31-01E

● Model MVRK Digital Limit Alarm (RTD Input Type) Document number: IM 77J04R31-01E

● Model MVTK Digital Limit Alarm (Thermocouple Input Type) Document number: IM 77J04T31-01E

The user's manuals above describe mounting, wiring, and how to operate the digital limit alarms.

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Documentation Conventions

■ Symbols

The following symbols are used in this manual.

● Symbols Used in the Main Text

CAUTION

Draws attention to information that is essential for understanding the operation and/or features of the product.

TIP

Gives additional information to complement the present topic.

Notices

■ Regarding This User's Manual

(1) This manual should be passed on to the end user. Keep the manual in a safe place. (2) Read this manual carefully to gain a thorough understanding of how to operate this

product before you start using it.

(3) This manual is intended to describe the functions of this product. Yokogawa Electric

Corporation (hereinafter simply referred to as Yokogawa) does not guarantee that these functions are suited to the particular purpose of the user.

(4) Under absolutely no circumstance may the contents of this manual, in part or in whole,

be transcribed or copied without permission.

(5) The contents of this manual are subject to change without prior notice. (6) Every effort has been made to ensure accuracy in the preparation of this manual.

Should any errors or omissions come to your attention however, please contact your nearest Yokogawa representative or our sales office.

iii

■ Regarding Protection, Safety, and Prohibition Against Unauthorized Modification

(1) In order to protect the product and the system controlled by it against damage and

ensure its safe use, be certain to strictly adhere to all of the instructions and precautions relating to safety contained in this document. Yokogawa does not guarantee safety if products are not handled according to these instructions.

(2) The following safety symbols are used on the product and/or in this manual.

● Symbols Used on the Product and in This Manual

CAUTION This symbol on the product indicates that the operator must refer to an explanation in

the user's manual in order to avoid the risk of injury or death of personnel or damage to the instrument. The manual describes how the operator should exercise special care to avoid electric shock or other dangers that may result in injury or loss of life.

Protective Grounding Terminal This symbol indicates that the terminal must be connected to ground prior to operating

the equipment.

Functional Grounding Terminal This symbol indicates that the terminal must be connected to ground prior to operating

the equipment.

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■ Force Majeure

(1) Yokogawa does not make any warranties regarding the product except those men-

tioned in the WARRANTY that is provided separately.

(2) Yokogawa assumes no liability to any party for any loss or damage, direct or indirect,

caused by the use or any unpredictable defect of the product.

(3) Be sure to use the spare parts approved by Yokogawa when replacing parts or

consumables. (4) Modification of the product is strictly prohibited. (5) Reverse engineering such as the disassembly or decompilation of software is strictly

prohibited. (6) No portion of the software supplied by Yokogawa may be transferred, exchanged,

leased or sublet for use by any third party without the prior permission of Yokogawa.

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M Series Digital Limit Alarms Communication Functions

Introduction........................................................................................................... i

Documentation Conventions ...............................................................................ii

Notices .................................................................................................................iii

1. Setup ....................................................................................................... 1-1

1.1 Setup Procedure ............................................................................................. 1-1

1.2 Notes on Setting Parameters ......................................................................... 1-2

2. Communication Specifications.............................................................. 2-1

2.1 RS-485 Communication Specifications ......................................................... 2-1

Toc-1

IM 77J04J11-01E 1st Edition

3. PC Link Communication ........................................................................ 3-1

3.1 Overview.......................................................................................................... 3-1

3.1.1 Configuration of Command ............................................................... 3-2

3.1.2 Configuration of Response ............................................................... 3-3

3.1.3 Response Error Codes ..................................................................... 3-4

3.1.4 Specifying Broadcast ........................................................................ 3-5

3.2 Commands ...................................................................................................... 3-6

3.2.1 List of Commands ............................................................................. 3-6

BRD Reads I relays on a bit-by-bit basis ......................................... 3-7

BWR

Writes data into I relays on a bit-by-bit basis ........................... 3-8

BRR Reads I relays on a bit-by-bit basis in random order ................ 3-9

BRW

Writes data into I relays on a bit-by-bit basis in random order ..

BRS Specifies I relays to be monitored on a bit-by-bit basis ........... 3-11

BRM Monitors I relays on a bit-by-bit basis .................................... 3-12

WRD

Reads D registers and I relays on a word-by-word basis ....... 3-13

WWR

Writes data into D registers and I relays on a word-by-word

basis..................................................................................... 3-14

WRR

Reads D registers and I relays on a word-by-word basis in

random order ........................................................................ 3-15

WRW

Writes data into D registers and I relays on a word-by-word

basis in random order ........................................................... 3-16

WRS

Specifies D registers and I relays to be monitored on a word-

by-word basis ....................................................................... 3-17

WRM

Monitors D registers and I relays on a word-by-word basis.... 3-18

INF Reads the model, range code number, number of alarms and

revision ................................................................................. 3-19

3-10

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4. Ladder Communication.......................................................................... 4-1

5. MODBUS Communication...................................................................... 5-1

Toc-2

3.3 Communication with Higher-level Devices ................................................. 3-20

3.3.1 Example of Communication Program Created Using Visual Basic .. 3-21

3.3.2 Communication with UT Link Module .............................................. 3-25

3.3.3 Communication with Touch Panel ................................................... 3-26

4.1 Overview.......................................................................................................... 4-1

4.2 Commands/Responses at the PLC ................................................................ 4-2

4.2.1 Configuration of Command/Response .............................................. 4-2

4.2.2 Reading Parameters......................................................................... 4-3

4.2.3 Writing Parameters ........................................................................... 4-4

4.2.4 Response Error Codes ..................................................................... 4-5

5.1 Overview.......................................................................................................... 5-1

5.1.1 Configuration of Message ................................................................. 5-2

5.1.2 Specifying D Registers...................................................................... 5-3

5.2 Function Codes ............................................................................................... 5-4

5.2.1 List of Function Codes ...................................................................... 5-4

03 Reads data from multiple D registers ...................................... 5-5

06 Writes data into a D register.................................................... 5-7

08 Performs loop back test .......................................................... 5-9

16 Writes data into multiple D registers ...................................... 5-10

5.2.2 Response Error Codes ................................................................... 5-12

5.2.3 Specifying Broadcast ...................................................................... 5-13

6. Functions and Usage of D Registers ..................................................... 6-1

6.1 Overview of D Registers ................................................................................. 6-1

6.2 Interpretation of D Register Map Table .......................................................... 6-1

6.3 D Register Map Table ...................................................................................... 6-2

6.3.1 Contents of D Registers .................................................................... 6-3

7. Functions and Usage of I Relays ........................................................... 7-1

7.1 Status............................................................................................................... 7-2

Appendix Table of ASCII Codes (Alphanumeric Codes).........................App.-1

Revision Information ............................................................................................ i

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1. Setup

This chapter describes the setup procedure required to use the communication functions (PC link, Ladder and MODBUS) and the communication parameters of the M Series.

1.1 Setup Procedure

Set up the communication functions on the M Series as follows:

Set up the communication function parameters of the M Series. (See section 1.2.)

Connect a higher-level device and a M Series. (See the connection diagram below.)

Create communication programs for the higher-level device to perform communication.

Note: Refer to the documentation of each higher-level device when creating communication programs.

• Connection

PLC

B (+)

A (-)

Terminating resistor

220 Ω 1/4 W

M Series M Series

B (+)

A (-)

B (+)

A (-)

1-1

Terminating resistor

220 Ω 1/4 W

Shielded

JIS Class D grounding (grounding resistance of 100 Ω or less)

PC or PLC

(straight cable)

(RS-232C/RS-485 converter)

RS-232C

ML2

B (+)

A (-)

JIS Class D grounding (grounding resistance of 100 Ω or less)

M Series M Series

B (+)

A (-)

JIS Class D grounding (grounding resistance of 100 Ω or less)

COMCOM

B (+)

A (-)

COMCOM

Terminating resistor

220 Ω 1/4 W

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1.2 Notes on Setting Parameters

This section describes the setting parameters for using the communication functions and their setting ranges.

CAUTION

The details of M Series communication functions need to be the same as those of the communication functions of the higher-level device to be connected. Check the communication parameters of the higher-level device first, then set up those of the M Series.

Table 1-1 Parameters to be Set for Communication Functions

1-2

Parameter Name

Protocol selection Without checksum (0)

Address Baud rate Parity Stop bit Data length

*1: When "Ladder communication" is selected in protocol selection, the data length is fixed to 8.

When "MODBUS communication" is selected, the data length is fixed to 7 for ASCII mode and to 8 for RTU mode.

Symbol

PSL

ADR

BPS

PRI STP DLN

Setting Range

PC link communication

With checksum (1)

MODBUS communication ASCII mode (3)

RTU mode (4)

Ladder (2)Ladder communication

1 to 99

1.2 (0), 2.4 (1), 4.8 (2), 9.6 (3) kbps NON (0), EVN (1), ODD (2)

1, 2

7, 8 (*1)

PC link communication

without checksum

● Protocol selection (PSL)

Set the communication protocol identical to that of the higher-level device to be connected.

Default

(0)

9.6 (3)

EVN (1)

1 8

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● Address number (ADR)

Set the address number of the M Series itself. An address number of 1 to 99 can be assigned in any order. Note that the number of M Series that can be connected to a single communication port is limited to 31.

Example of connecting four M Series to a higher-level device by setting address numbers of 1, 5, 10 and 20

A maximum of 1200 m; up to 31 slave stations

1-3

ADR=1 ADR=20ADR=10ADR=5

● Baud rate (BPS)

Set the baud rate identical to that of the higher-level device to be connected. (Otherwise, proper communication cannot be achieved.) The unit of the baud rate is kbps (kbits per second).

● Parity (PRI)

Set the handling of parity to be carried out when data is sent or received. Set the parity bit state identical to that of the higher-level device to be connected.

● Stop bit (STP)

Set the stop bit identical to that of the higher-level device to be connected.

● Data length (DLN)

Set the data length identical to that of the higher-level device to be connected. (When Ladder or MODBUS communication is selected in protocol selection, the data length is fixed.)

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2. Communication Specifications

The RS-485 communication interface has the PC link communication, Ladder communication and MODBUS communication protocols.

Table 2-1 M Series Communication Specifications

2-1

Communication Hardware Terminal

Communication Protocol Specifications

Maximum Baud Rate

Table 2-2 Types of Devices to be Connected

Connected Device

PC PC, touch panel and PLC

(FA-M3 UT link module)

PLC (sequencer) (FA-M3 ladder communication module)

2-wire RS-485 communication system Two-piece connector on the front panel: 1, 2, 3

PC link communication without checksum PC link communication with checksum MODBUS communication (ASCII mode) MODBUS communication (RTU mode) Ladder communication

9600 bps

Communication Protocol

MODBUS communication PC link communication

Ladder communication

Example of Connected Device

General-purpose PC General-purpose PC, FA-M3

and GP Series

General-purpose PLC (sequencer)

2.1 RS-485 Communication Specifications

Table 2-3 RS-485 Communication Interface

Item

Compliant standard EIA, RS-485 Maximum number of devices to be connected 31 Communication system Synchronization Asynchronous (start-stop)

Maximum communication distance 1200 m Baud rate 1200, 2400, 4800, 9600

2-wire, half duplex

No handshakingCommunication method

Specifications

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3. PC Link Communication

3.1 Overview

The use of PC link communication enables the M Series to communicate with a device such as a PC, graphic panel and FA-M3 UT link module easily. In this communication, you can use such device to read/write data from/into D registers or I relays, both of which are internal registers of the M Series.

A maximum of 1200 m; up to 31 slave stations

3-1

Figure 3-1 Example of Connection for PC Link Communication

Hereafter, PCs etc. are generically called "higher-level devices."

3.1.1 Configuration of Command

Commands sent from a higher-level device to the M Series consist of the following elements.

3-2

Number of Bytes 1 2 2 1 3 2 1 1

Element STX Address

number

(ADR)

(1) (2) (3) (4) (5) (7) (8) (9)(6)

CPU

number

Time to wait

for response

Command Data

Variable length

Checksum ETX CR

corresponding

to command

(1) STX (Start of Text)

This control code indicates the start of a command. The ASCII code is 02 in hexadecimal.

(2) Address Number (01 to 99)

Adress numbers are used by a higher-level device to identify the M Series at the communication destination. (Identification numbers specific to individual M Series.)

(3) CPU Number

This is fixed to 01.

(4) Time to Wait for Response

This is fixed to 0.

(5) Command (See subsection 3.2.)

This specifies a command to be issued from the higher-level device.

(6) Data Corresponding to Command

This specifies an internal register (D register or I relay), number of data pieces and others.

(7) Checksum

This converts the ASCII codes of texts between the character next to STX and the character immediately before the checksum into hexadecimal values and adds them byte by byte. It then fetches the single lowermost byte of the added results as the checksum.

This column is only required for PC link communication with checksum. PC link communication without checksum does not require this 2-byte space of ASCII code.

(8) ETX (End of Text)

This control code indicates the end of a command string. The ASCII code is 03 in hexadecimal.

(9) CR (Carriage Return)

This control code indicates the end of a command. The ASCII code is 0D in hexadecimal.

CAUTION

The control codes STX, ETX and CR are essential for commands when you create a communication program for PC link communication. Omission of any of them or incorrect order of them results in communication failure.

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3.1.2 Configuration of Response

Responses from the M Series with respect to a command sent from the higher-level device consist of the following elements, which differ depending on the condition of communication; normal or failure.

1) Normal Communication

If communication succeeded, a character string "OK" is returned with the data corresponding to a command.

Number of Bytes Variable length12 22 211

Element STX Address

number

(ADR)

CPU

number

2) In the Event of Failure

If communication failed, a character string "ER" is returned with error codes (EC1 and EC2). (See subsection 3.1.3, "Response Error Codes.")

• No response is returned in case of an error in address number specification or CPU number specification.

• If ETX in a command cannot be received, a response may not be returned.

Note: As a countermeasure, provide a timeout process in the communication functions of the higher-level device or in

communication programs.

Number of Bytes 1 2 2 2 2 2 3 2 1 1

Element STX ER EC1 EC2 Command Checksum ETX CRAddress

number

(ADR)

CPU

number

OK Parameter data Checksum ETX CR

3-3

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3.1.3 Response Error Codes

3.1.4 Specifying Broadcast

Broadcast addressing allows the corresponding multiple M Series to receive the command. (1) To use this function, specify BM for the address number in a command. (2) Broadcast addressing works independently of the address number. (3) Broadcast addressing is only applicable to write commands. (4) No response is returned if broadcast addressing is used.

Higher-level device (master)

Broadcast data.

* No response from slaves

A maximum of 1200 m; up to 31 slave stations

3-5

For the M Series communication, D registers and I relays are used.

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3.2 Commands

3.2.1 List of Commands

The following shows lists of commands available in PC link communication. Their details are explained in the description of each command.

(1) Bit-basis Access Commands Dedicated to I Relays

Command Description Number of Bits to be Handled

BRD BWR Bit-basis write 1 to 256 bits

BRR Bit-basis random read BRW Bit-basis random write 1 to 32 bits

BRS Specifies registers to be monitored on a bit-by-bit basis.

BRM

(2) Word-basis Access Commands

Command Description Number of Words to be Handled

WRD

WWR

WRR

WRW

WRS

WRM

Bit-basis read

Bit-basis monitoring

Word-basis read Word-basis write

Word-basis random read Word-basis random write Specifies registers to be monitored on a word-by-word basis. Word-basis monitoring

1 to 256 bits

1 to 32 bits

1 to 64 words 1 to 64 words

1 to 32 words 1 to 32 words 1 to 32 words

3-6

(3) Information Command

Command Description Number of Units to be Handled

INF1Reads model, input range code, number of alarms

and revision.

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BRD Reads I relays on a bit-by-bit basis

● Function

Reads the ON/OFF statuses of a sequence of contiguous I relays by the specified number of bits, starting at a specified I relay number.

• The number of bits to be read at a time is 1 to 256.

• For the format of response in the event of failure, see subsection 3.1.2.

• The command shown below includes the checksum function.

When performing communication without checksum, do not include the 2-byte checksum element in the command.

● Command/Response (for normal operation)

Number of Bytes 1 2 2 1 3 5 1 3 2 1 1

Command

element

STX Address

number

(ADR)

CPU

number

0 BRD ETX CRI relay

number

Comma

or space

Number

of bits

(n)

Checksum

3-7

Number of Bytes

element

Responses 0 and 1 indicate OFF and ON respectively.

dn: read data of the specified number of bits (n=1 to 256)

dn=0 (OFF)

dn=1 (ON)

1 2 2 2111 1 2 1 1

CPU

STX Address

number

(ADR)

number

OK d1 d2 d3 ETX CRResponse

● Example:

Reading the status of alarm 1 of the M Series with address number 01. The following command reads the status of alarm 1 (

[Command]

[STX]01010BRDI0001,00191[ETX][CR]

The following response is returned with respect to the above command. (Alarm 1 is ON.)

[Response]

[STX]0101OK18D[ETX][CR]

• • •

• • • dn Checksum

I0001) of address number 01.

Alarm has been ON since 1 was returned.

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+ 49 hidden pages

Yokogawa M Series User Manual

Introduction

Documentation Conventions

Notices

CONTENTS

1. Setup

1.1 Setup Procedure

1.2 Notes on Setting Parameters

2. Communication Specifications

2.1 RS-485 Communication Specifications

3. PC Link Communication

3.1 Overview

3.1.1 Configuration of Command

3.1.2 Configuration of Response

3.1.3 Response Error Codes

3.1.4 Specifying Broadcast

3.2 Commands

3.2.1 List of Commands

BRD Reads I relays on a bit-by-bit basis