Yokogawa PR300 User Manual

User’s
Manual

Model PR300
Power and Energy Meter
Communication Interface

(RS-485 and Ethernet Communications)

IM 77C01E01-10E

IM 77C01E01-10E

4th Edition

<Toc> <Ind> <Rev>

Introduction

This user's manual describes the communication functions of the PR300 power and energy
meter and contains information on how to create communication programs.

Hereafter, the PR300 power and energy meter is simply referred to as the PR300.
Read the manual carefully to understand the communication functions of the PR300 .

The PR300 has the following communication protocols.

● PC link communication protocol

● Modbus /RTU and Modbus/ASCII communication protocols

● Modbus/TCP communication protocol (for the PR300 with Ethernet communication

function)

● PR201 original communication protocol

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.

i

■ Intended Readers

This manual is intended for people familiar with the functions of the PR300, 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 PR300. Read
them as necessary.

● Model PR300 Power and Energy Meter User's Manual (electronic manual)
Document number: IM 77C01E01-01E

● Model PR300 Power and Energy Meter Startup Manual <Installation>
Document number: IM 77C01E01-02E

● Model PR300 Power and Energy Meter Startup Manual <Initial Setup Operations>
Document number: IM 77C01E01-03E

These manuals provide information about the procedure of installation, wiring and opera­tion.

■ Trademark

(1) All the brands or names of Yokogawa Electric's products used in this manual are

either trademarks or registerd trademarks of Yokogawa Electric Corporation.

(2) Ethernet is a registered trademark of XEROX Corporation in the United States.
(3) Company and product names that appear in this manual are trademarks or registered

trademarks of their respective holders.

Media No. IM 77C01E01-10E 3rd Edition : Feb. 15, 2007 (YK)
All Rights Reserved Copyright © 2006, Yokogawa Electric Corporation

IM 77C01E01-10E

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Documentation Conventions

■ Symbols

This manual uses the following symbols.

● Symbols Used in the Main Text

NOTE

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.

See Also

ii

Gives reference locations for further information on the topic.

● Symbols Used in Figures and Tables

[NOTE]

Draws attention to information that is essential for understanding the features of the
product.

[TIP]

Gives additional information to complement the present topic.

[See Also]

Gives reference locations for further information on the topic.

■ Description of Displays

(1) Some of the representations of product displays shown in this manual may be exag-

gerated, simplified, or partially omitted for reasons of convenience when explaining
them.

(2) Figures and illustrations representing the PR300's displays may differ from the real

displays in regard to the position and/or indicated characters (upper-case or lower­case, for example), the extent of difference does not impair a correct understanding of
the functions and the proper operations and monitoring of the system.

IM 77C01E01-10E

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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.

(7) The document concerning TCP/IP software has been created by Yokogawa based on

the BSD Networking Software, Release 1 that has been licensed from the University
of California.

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

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.

IM 77C01E01-10E

<Toc> <Ind> <Rev>

■ 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.

iv

IM 77C01E01-10E

<Int> <Ind> <Rev>

Model PR300 Power and Energy Meter
Communication Interface

Toc-1

(RS-485 and Ethernet Communications)

IM 77C01E01-10E 4th Edition

CONTENTS

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

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

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

1. Communications Overview

1.1 RS-485 Communication Specifications ......................................................... 1-1

1.2 Ethernet Communication Specifications....................................................... 1-1

2. Setup

2.1 Setup Procedure ............................................................................................. 2-1

2.1.1 Procedure for RS-485 Communication ............................................. 2-2

2.1.2 Procedure for Ethernet Communication ............................................ 2-3

2.1.3 Procedure for Ethernet-Serial Gateway Function .............................. 2-4

2.2 Setting Communication Conditions .............................................................. 2-6

2.2.1 Conditions for RS-485 Communication ............................................. 2-6

2.2.2 Conditions for Ethernet Communication ............................................ 2-8

2.2.3 Conditions for Ethernet-Serial Gateway Function ............................ 2-10

2.3 Wiring for Communication ........................................................................... 2-12

2.3.1 Wiring for RS-485 Communication .................................................. 2-12

2.3.2 Wiring for Ethernet Communication ................................................ 2-13

2.3.3

Wiring for RS-485 Communication for Ethernet-Serial Gateway Function ..

2-14

3. Procedures for Setting PR300 Functions

3.1 Basic Setting ................................................................................................... 3-2

3.1.1 Setting of VT Ratio ............................................................................ 3-2

3.1.2 Setting of CT Ratio............................................................................ 3-3

3.1.3 Setting of Integrated Low-cut Power ................................................. 3-4

3.2 Setting Pulse Output....................................................................................... 3-5

3.2.1 Selection of Measurement Item for Pulse Output .............................. 3-5

3.2.2 Pulse Unit ......................................................................................... 3-6

3.2.3 ON Pulse Width ................................................................................ 3-7

3.3 Setting Analog Output .................................................................................... 3-8

3.3.1 Selection of Measurement Item for Analog Output ............................ 3-8

3.3.2 Upper/Lower Limits of Scaling .......................................................... 3-9

3.4 Demand Setting ............................................................................................ 3-10

3.4.1 Demand Power/Current .................................................................. 3-10

3.4.2 Demand Period................................................................................3-11

3.4.3 Demand Alarm Mask Time .............................................................. 3-12

3.4.4 Demand Power Alarm Point ............................................................ 3-13

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3.4.5 Demand Current Alarm Point .......................................................... 3-14

3.4.6 Demand Alarm Release Function ................................................... 3-15

3.5 Communication Setting ................................................................................ 3-16

3.5.1 Protocol .......................................................................................... 3-16

3.5.2 Baud Rate ...................................................................................... 3-17

3.5.3 Parity .............................................................................................. 3-18

3.5.4 Stop Bit ........................................................................................... 3-19

3.5.5 Data Length .................................................................................... 3-20

3.5.6 Station Number............................................................................... 3-21

3.5.7 IP Address (for Ethernet communication) ........................................ 3-22

3.5.8 Subnet Mask (for Ethernet communication) .................................... 3-23

3.5.9 Default Gateway (for Ethernet communication) ............................... 3-24

3.5.10 Port Number (for Ethernet communication) ..................................... 3-25

3.6 Writing Energy Values .................................................................................. 3-26

3.6.1 Active Energy ................................................................................. 3-26

3.6.2 Regenerative Energy ...................................................................... 3-27

3.6.3 LEAD Reactive Energy ................................................................... 3-28

3.6.4 LAG Reactive Energy ..................................................................... 3-29

3.6.5 Apparent Energy............................................................................. 3-30

3.7 Executing Reset Operations ........................................................................ 3-31

3.7.1 Remote Reset ................................................................................ 3-31

3.7.2 Maximum/Minimum Values Reset ................................................... 3-32

3.7.3 Energy Value All-Reset ................................................................... 3-32

3.7.4 Active Energy Reset ....................................................................... 3-33

3.7.5 Regenerative Energy Reset ............................................................ 3-33

3.7.6 Reactive Energy Reset ................................................................... 3-34

3.7.7 Apparent Energy Reset .................................................................. 3-34

3.8 Setting Control States .................................................................................. 3-35

3.8.1 Integration Start/Stop ..................................................................... 3-35

3.8.2 Optional Integration Start/Stop ........................................................ 3-36

3.8.3 Demand Measurement Start/Stop................................................... 3-37

3.8.4 Confirmation and Release of Demand Alarm State ......................... 3-38

4. PC Link Communication Protocol

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

4.1.1 Configuration of Command ............................................................... 4-2

4.1.2 Configuration of Response ............................................................... 4-3

4.1.3 Response Error Codes ..................................................................... 4-4

4.1.4 Specifying Broadcast ........................................................................ 4-5

4.2 Command and Response ............................................................................... 4-6

WRD Reads D registers on a word-by-word basis ................................... 4-7

WWR Writes data into D registers on a word-by-word basis..................... 4-8

WRR Reads D registers on a word-by-word basis in random order......... 4-9

WRW
WRS

WRM Monitors the D registers on a word-by-word basis ........................ 4-12

INF6 Reads the model, suffix codes, and version information............... 4-13

INF7 Reads the maximum value of CPU ............................................... 4-14

4.3 Communication with Higher-level Devices ................................................. 4-15

4.3.1 Communication with FA-M3 (UT Link Module) ................................ 4-15

Writes data into D registers on a word-by-word basis in random order ...

Specifies the D registers to be monitored on a word-by-word basis ........

4-10
4-11

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5. Modbus/RTU and ASCII Communication Protocols

6. Modbus/TCP Communication Protocol

Toc-3

4.4 Sample Program ........................................................................................... 4-17

4.4.1 Example of BASIC Program for Send and Receive ......................... 4-17

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

5.1.1 Configuration of Message ................................................................. 5-3

5.1.2 Specifying D Registers...................................................................... 5-4

5.1.3 Checking Errors ................................................................................ 5-4

5.1.4 Configuration of Response ............................................................... 5-7

5.1.5 Specifying Broadcast ........................................................................ 5-9

5.2 Message and Response ............................................................................... 5-10

03 Reads data from multiple D registers ............................................ 5-11

06 Writes data into D register ............................................................. 5-12

08 Performs loop back test................................................................. 5-13

16 Writes data into multiple D registers .............................................. 5-14

6.1 Overview.......................................................................................................... 6-1

6.2 TCP/IP Communication .................................................................................. 6-3

6.3 Network Frame Structure ............................................................................... 6-4

6.3.1 MBAP Header Structure ................................................................... 6-4

6.3.2 PDU Structure .................................................................................. 6-4

6.4 Communication with Higher-level Devices ................................................... 6-5

6.4.1 List of Function Codes ...................................................................... 6-5

6.4.2 Specifying D Registers...................................................................... 6-5

6.4.3 Request and Response .................................................................... 6-6

03 Reads data from multiple D registers .............................................. 6-6

06 Writes data into D register ............................................................... 6-7

08 Performs loop back test................................................................... 6-8

16 Writes data into multiple D registers ................................................ 6-9

6.4.4 Response Error Codes .................................................................... 6-11

6.5 Sample Program ........................................................................................... 6-12

6.5.1 Example of BASIC Program for Send and Receive ......................... 6-12

7. Functions and Usage of D Registers

7.1 Overview of D Registers ................................................................................. 7-1

7.2 Configuration of D Registers.......................................................................... 7-1

7.3 Interpretation of D Register Map Table .......................................................... 7-1

7.4 D Register Map ................................................................................................ 7-2

8. PR201 Original Communication Protocol

8.1 Overview.......................................................................................................... 8-1

8.2 Communication Specifications ...................................................................... 8-1

8.3 Command/Response Format ......................................................................... 8-2

8.4 List of Commands........................................................................................... 8-3

8.5 Command Details............................................................................................ 8-5

Appendix Table of ASCII Codes (Alphanumeric Codes)
Revision Information

IM 77C01E01-10E

<Toc> <Ind> <1. Communications Overview >

1. Communications Overview

1.1 RS-485 Communication Specifications

Protocols available for RS-485 communication interfaces include the PC link com­munication protocol and the Modbus communication protocol.

Table 1.1 RS-485 Communication Specifications

Item Details Connected Device
Communication Hardware
Compliant Standard

Protocol Specification

Baud Rate
Maximum Communication Distance
Maximum Number of

Connectable Devices
Transmission Method
Synchronization
Communication Method
Communication Cable

2-wire system RS-485
EIA RS-485

PC Link Communication with
and without checksum

Modbus Communication
(ASCII and RTU modes)

PR201 original communication

2400 bps, 9600 bps, 19200 bps
1200 m

31
2-wire, half-duplex

Start-stop synchronization
Non-procedural
Shielded twisted pair cable

(AWG24-equivalent size)

A PC installed with a driver for PC link
communication and SCADA software,
PLC (FA-M3 UT link module), etc.

A PC installed with a Modbus driver
and SCADA software,
a Modbus-compatible PLC, etc.

Personal computer etc. with SCADA
software installed to support PR201
original communication protocol

1-1

1.2 Ethernet Communication Specifications

Protocols available for Ethernet communication interfaces include the Modbus/TCP
communication protocol.

Table 1.2 Ethernet Communication Specifications

Item Details

Communication Hardware
Compliant Standard
Access Control
Protocol Specification
Baud Rate
Maximum Segment Length
Maximum Connecting

Configuration
Communication System
Data Format
Maximum Number of

Connections
*1: Distance between the hub and module.

*2: The number of hubs connectable in cascade configuration.

10BASE-T/100BASE-TX
Ethernet IEEE802.3
CSMA/CD
Modbus communication (Port No.: 502)
10 Mbps/100 Mbps
100 m *1
Cascade max. 4 levels (for 10BASE-T)

max. 2 levels (for 100BASE-TX) *2
TCP/IP
Binary
1

Connected Device

Ethernet-equipped PC etc.

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2. Setup

This chapter describes how to set up the PR300, which is equipped with RS-485
communication as a standard feature.

When using an Ethernet-equipped model, either RS-485 or Ethernet can be selected
by parameter setting for communications.

For details of use of RS-485 communication, see subsection 2.1.1 “Procedure for
RS-485 Communication.”

For details of use of the Ethernet communication, see subsection 2.1.2 “Procedure
for Ethernet Communication.”

For details of use of the Ethernet-serial gateway function, see subsection 2.1.3
“Procedure for Ethernet-Serial Gateway Function.”

2.1 Setup Procedure

Set up the communication functions on the PR300 as follows:

2-1

WARNING

To avoid an electric shock, be sure to turn off the power supply source to the equipment
involved before you start wiring.

Note: Create communication programs referring to the user’s manual for communications of each higher-level device.

Higher-level devices : PCs, PLCs (sequencers), and others.

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2.1.1 Procedure for RS-485 Communication

(Example)

Higher-level device

Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31

2-2

Station number 01

(arbitrary)

Communication parameters setting for PR300

1

Set up the communication function using
the front panel keys.

Connect a higher-level device with PR300

2

Create communication programs for the

3

higher-level device to perform
communication

Station number 02

(arbitrary)

Subsection 2.2.1 “Conditions for RS-485
Communication”

Subsection 2.3.1
“Wiring for RS-485 Communication”

Chapter 3
“Procedures for Setting PR300 Functions”

For communication protocol, see
Chapter 4
“PC Link Communication Protocol”
Chapter 5

Modbus/RTU and ASCII Communication Protocols

“
Chapter 8
“PR201 Original Communication Protocol”

For data storage location, see
Chapter 7
“Functions and Usage of D Registers”

See

See

See

Station number 10

(arbitrary)

Station number 20

(arbitrary)

”

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<Toc> <Ind> <2. Setup>

2.1.2 Procedure for Ethernet Communication

(Example)

2-3

Higher-level device
IP address [192.168.1.1]

HUB

LAN
connection

Station number 01 (fixed)
IP address [192.168.1.2]
(arbitrary)

Communication parameters setting for PR300

1

Set up the communication function using

(arbitrary)

Ethernet

Station number 01 (fixed)
IP address [192.168.1.3]
(arbitrary)

the front panel keys.

See

Subsection 2.2.2 “Conditions for Ethernet
Communication”

Connect a higher-level device with PR300

2

See

Subsection 2.3.2
“Wiring for Ethernet Communication”

Maximum distance between hub and module: 100 m
Maximum number of hubs connectable in cascade configuration:
4 levels for 10BASE-T
2 levels for 100BASE-TX

Station number 01 (fixed)
IP address [192.168.1.4]
(arbitrary)

Station number 01 (fixed)
IP address [192.168.1.5]
(arbitrary)

Create communication programs for the

3

higher-level device to perform
communication

See

Chapter 3
“Procedures for Setting PR300 Functions”

For communication protocol, see
Chapter 6

“Modbus/TCP Communication Protocol”

For data storage location, see
Chapter 7
“Functions and Usage of D Registers”

Note: It is recommended to use the Ethernet network as a dedicated one for the

PR300.

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<Toc> <Ind> <2. Setup>

2.1.3 Procedure for Ethernet-Serial Gateway Function

(Example)

Higher-level device
IP address [192.168.1.1] (arbitrary)

Ethernet

2-4

PR300

communication function)

(with Ethernet

Communication parameters setting for PR300

1

Set up the communication function using
the front panel keys.

Connect a higher-level device with PR300

2

RS-485

Station number 02

(arbitrary)

Subsection 2.2.2
“Conditions for Ethernet Communication”
Subsection 2.2.3
“

Subsection 2.3.2
“Wiring for Ethernet Communication”

Station number 01 (fixed)
IP address [192.168.1.2] (arbitrary)

Station number 03

(arbitrary)

See

Conditions for Ethernet-Serial Gateway Function

See

Station number 20

(arbitrary)

”

Connect a lower-level device with PR300

3

See

Subsection 2.3.3
“Wiring for RS-485 Communication for
Ethernet-Serial Gateway Function”

Create communication programs for the

4

higher-level device to perform
communication

Note: It is recommended to use the Ethernet network as a dedicated one for the PR300.

See

Chapter 3
“Procedures for Setting PR300 Functions”

For communication protocol, see
Chapter 6

“Modbus/TCP Communication Protocol”

For data storage location, see
Chapter 7
“Functions and Usage of D Registers”

IM 77C01E01-10E

<Toc> <Ind> <2. Setup>

●

VJET Ethernet/RS-485 converter as an Ethernet-serial gateway function

(Example)

Higher-level device
IP address [192.168.1.1] (arbitrary)

Ethernet

2-5

Ethernet/RS-485 converter

VJET*

RS-485

Station number 02 (arbitrary) Station number 03 (arbitrary)

* The VJET is Yokogawa’s converter. For details of use of the VJET, refer to its user’s manual.

Note: It is recommended to use the Ethernet network as a dedicated one for the PR300.

The communication conditions of any slave PR300 must conform to those of the VJET at
a higher level.

Station number 01 (fixed)
IP address [192.168.1.2] (arbitrary)

Station number 20 (arbitrary)

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2.2 Setting Communication Conditions

This section describes the setting parameters for using the communication func­tions, and the setting ranges. For details of setting method, refer to the PR300
Power and Energy Meter User’s Manual (electronic manual).

2.2.1 Conditions for RS-485 Communication

This subsection describes the setting parameters for using the RS-485 communication
function, and the setting ranges.

Table 2.1 Parameters to be Set for Communication Functions

Parameter Name

Menu

Parameter Symbol

Setting Range

2-6

Initial

Value

Station number

Protocol

Baud rate

3

Parity*

Stop bit*

3

(RS-485

communication)

(ST-NO)

(COMM)

(B-RT)

(PRI)

(STP)

01 to 99 (01 to 31 recommended)

PC link without checksum

PC link with checksum

Modbus/ASCII

Modbus/RTU

Modbus/TCP*

PR201 original

1

(PCLK1)

(PCLK2)

(M ASC)

(M RTU)

(M TCP)

(PR201)

2400 bps
9600 bps
19200 bps

None

Even

Odd

(NONE)

(EVEN)

(ODD)

1

2

01

PCLK2

9600

NONE

1

Data length*2 *

*1: Modbus/TCP can be selected for the PR300 with Ethernet communication function only.
*2: When Modbus /RTU is selected for the protocol, select 8 for the data length. If 7 is selected for the data length,

communication is not possible.

*3: When PR201 original is selected for the protocol, select NONE for the parity, 1 for the stop bit and 8 for the data length.

3

(DLN)

7

8

8

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● Protocol (COMM)

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

● Station number (ST-NO)

Set the station number of the PR300 itself. A station number of 01 to 99 may be assigned
in any order. However, the maximum number of PR300 to be connected to a single com­munication port is 31.

When connecting two or more PR300 to a single communication port, set a different station
number to each.

Example of connecting a higher-level device with four PR300 having station numbers 01,
05, 10, and 20

(Example)

Higher-level device

2-7

Maximum communication distance: 1200 m
Maximum number of slave sations to be connected: 31

Station number 01

(arbitrary)

Station number 05

(arbitrary)

Station number 10

(arbitrary)

Station number 20

(arbitrary)

● Baud rate (B-RT)

Set the baud rate identical to that of the higher-level device to be connected. (Otherwise,
proper communication cannot be achieved.)

● 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.

* When PR201 original is selected for the protocol, select NONE for the parity.

● Stop bit (STP)

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

* When PR201 original is selected for the protocol, select 1 for the stop bit.

● Data length (DLN)

Set the same data length as for the upper device that is to be connected.

* When Modbus/RTU is selected for the protocol, select 8 for the data length.
* When PR201 original is selected for the protocol, select 8 for the data length.

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2.2.2 Conditions for Ethernet Communication

This subsection describes the setting parameters for using the Ethernet communication
function, and the setting ranges.

Table 2.2 Parameters to be Set for Communication Functions

Parameter Name

Menu

Parameter Symbol

Setting Range

2-8

Initial

Value

Protocol

IP address-1

IP address-2

IP address-3

IP address-4

Subnet mask-1

Subnet mask-2

(RS-485

Communication)

(COMM)

(IP-1)

(IP-2)

(IP-3)

(IP-4)

(SM-1)

(SM-2)

PC link without checksum

PC link with checksum

Modbus/ASCII

Modbus/RTU

Modbus/TCP*

1

PR201 original

0 to 255

0 to 255

0 to 255

0 to 255

0 to 255

0 to 255

(PCLK1)

(PCLK2)

(M ASC)

(M RTU)

(M TCP)

(PR201)

PCLK2

192

168

1

1

255

255

Subnet mask-3

(SM-3)

(Ethernet

Subnet mask-4

Communication)

2

*

(SM-4)

Default gateway-1

(DG-1)

Default gateway-2

(DG-2)

Default gateway-3

(DG-3)

Default gateway-4

(DG-4)

Port number

(PORT)

Ethernet setting switch

(E-SW)

*1: Modbus/TCP can be selected for the PR300 with Ethernet communication function only.
*2: Ethernet communication menu is displayed when Modbus/TCP is selected for the protocol.

0 to 255

0 to 255

0 to 255

0 to 255

0 to 255

0 to 255

502, 1024 to 65535

OFF, ON

255

0

0

0

0

0

502

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<Toc> <Ind> <2. Setup>

● Protocol (COMM)

Set the protocol to Modbus/TCP.

● IP address-1 to 4 (IP-n) [n: integers from 1 to 4]

Set the IP address for the PR300 by the following format.

2-9

0 to 255

IP address IP-1

0 to 255

IP-2

0 to 255

IP-3

0 to 255

IP-4

● Subnet mask-1 to 4 (SM-n) [n: integers from 1 to 4]

Set the subnet mask for the PR300 by the following format.

0 to 255

Subnet Mask SM-1

0 to 255

SM-2

0 to 255

SM-3

0 to 255

SM-4

● Default gateway-1 to 4 (DG-n) [n: integers from 1 to 4]

Set the default gateway for the PR300 by the following format.

0 to 255

Default Gateway DG-1

0 to 255

DG-2

0 to 255

DG-3

0 to 255

DG-4

NOTE

Before performing setup of IP address, subnet mask, and default gateway, consult the
administrator for the network to which the PR300 is to be connected.

● Port number (PORT)

Set the port number for the PR300.

NOTE

To activate the settings of IP address, subnet mask, default gateway, and port number, set
the Ethernet setting switch to ‘ON’ after setting them.

● Ethernet setting swtich (E-SW)

This switch activates the Ethernet communication parameters settings. Setting this param­eter to ON activates the settings of IP address, subnet mask, default gateway, and port
number.

This parameter automatically reverts to OFF in about 20 seconds after being set to ON.

IM 77C01E01-10E

<Toc> <Ind> <2. Setup>

2.2.3 Conditions for Ethernet-Serial Gateway Function

The Ethernet-serial gateway function is a function that reads/writes data from/to other
devices equipped with RS-485 serial communication function using the Modbus/TCP
protocol via the PR300.

With this function, the higher-level device can access the devices connected to the RS-485
serial communication line in the same way as to access the devices connected to Ethernet.

(Example)

Higher-level device

2-10

PR300

communication function)

Device with RS-485 serial
communication function

Power Monitor of POWERCERT series
Digital indicating controller of
GREEN series
Signal conditioner of JUXTA series

(with Ethernet

Ethernet

RS-485

Station number 02

(arbitrary)

10BASE-T, 100BASE-TX

Station number 01 (fixed)

Station number 03

(arbitrary)

Station number 04

(arbitrary)

The PR300 operates as a gateway that changes the Modbus/TCP protocol received via
network to the Modbus/RTU protocol for the serial devices connected to the RS-485
communication interface. Therefore, the devices supporting the Modbus/RTU protocol are
required for the devices to be connected.

NOTE

• If the Ethernet-serial gateway function is used, set a station number other than 01 for
the RS-485 communication devices which are slaves of the PR300 connected to
Ethernet.

• If the Ethernet communication function is used, the RS-485 communication interface
is used specifically for the Ethernet-serial gateway function. Therefore, it is not pos­sible for a higher-level device such as a PC to access the PR300 via the RS-485
communication interface.

IM 77C01E01-10E

<Toc> <Ind> <2. Setup>

● Setting for PR300 to perform the Ethernet-serial gateway function

To use the Ethernet-serial gateway function, set the parameters of subsection 2.2.2, “Con­ditions for Ethernet Communication” and set a parity (PRI) in Table 2.3.

When the protocol is set to Modbus/TCP, the parameters of RS-485 other than the parity
are fixed and unchangeable.

Table 2.3 Parameters of PR300 to Perform the Ethernet-Serial Gateway Function

Parameter Name

Menu Setting Range

Parameter Symbol

2-11

Initial
Value

Station number

Baud rate

Parity

Stop bit

Data length

(RS-485

communication)

(ST-NO)

(B-RT)

(PRI)

(STP)

(DLN)

01 (fixed)

9600 bps (fixed)

None
Even

Odd

1 (fixed)

8 (fixed)

NONE
EVEN
ODD

● Slave PR300

The station number of any slave PR300 (device for RS-485 communication) must be a
different number other than 01.

The communication conditions for any slave PR300 (device for RS-485 communication)
other than the station number must conform to those in Table 2.3.

Table 2.4 Parameters of Slave PR300

Parameter Name

Station number

Baud rate

Parity

Stop bit

Menu Setting Range

(RS-485

communication)

Parameter Symbol

(ST-NO)

(B-RT)

(PRI)

(STP)

02 to 99

2400 bps
9600 bps
19200 bps

None
Even
Odd

1

2

NONE
EVEN
ODD

01

9600

NONE

1

8

Initial

Value

01

9600

NONE

1

Data length

(DLN)

8

8

When using the VJET Ethernet/RS-485 converter as an Ethernet-serial gateway function,
the communication conditions of any slave PR300 must conform to those of the VJET at a
higher level. The initial value of the VJET parity is EVEN.

IM 77C01E01-10E

7

<Toc> <Ind> <2. Setup>

2.3 Wiring for Communication

Connect a higher-level device with the PR300 for using the communication func­tions. The wiring procedures and precautionary notes are as follows.

2.3.1 Wiring for RS-485 Communication

For a common PC, the RS-485 interface is not directly connectable. Use a ML2 RS232C/
RS485 converter for wiring.

WARNING

To avoid an electric shock, be sure to turn off the power supply source to the equipment
involved before you start wiring.

Use crimp-on terminals at cable ends.
Before you start wiring, read the user’s manual of each device.

PR300
(with RS-485
communication function)

17

Aⴚ

18

Bⴙ

19

PC

(RS232C/RS485 converter)

Terminator

120Ω 1/4W

3

4

Aⴚ

Bⴙ

PR300
(with RS-485
communication function)

18

19

2-12

Terminator (built-in)

120Ω 1/4W

Wthen terminating on
wiring, short-circuit
terminals 17 and 18 .

SG

RS-232C
straight cable

SG

5

6

JIS Class D (3) grounding
(grounding resistance
of 100Ω or less)

20

Communication cableCommunication cable

JIS Class D (3) grounding
(grounding resistance
of 100Ω or less)

Note: Use UL Listed RS-232C/RS-485 converter if the converter has AC/DC power supply input; this is

optional for converters supplied by a Limited Power Source with input voltages less than 30 V AC or
60 V DC and which are separated from mains by double or reinforced insulation.

Communication cable: Shielded twisted pair cable (AWG24-eqivalent size)
Recommended terminals: See the PR300 Power and Energy Meter User’s Manual (electronic manual).

20

IM 77C01E01-10E

<Toc> <Ind> <2. Setup>

2.3.2 Wiring for Ethernet Communication

To use the Ethernet communication function, connect a higher-level device with the PR300
with Ethernet communication function using 10BASE-T/100BASE-TX. 10BASE-T/
100BASE-TX are Ethernet connection methods using twisted pair cables. The transmission
rates are 10 Mbps/100 Mbps. In 10BASE-T/100BASE-TX networks, higher-level devices
such as a PC are connected in a star pattern through a hub.

WARNING

To avoid an electric shock, be sure to turn off the power supply source to the equipment
involved before you start wiring.

Use hubs and twisted pair cables that conforms to the Ethernet specifications. The maxi­mum number of hubs connectable in cascade configuration is 4 for 10ABSE-T and 2 for
100BASE-TX. The maximum allowable length of twisted pair cables is 100 meters.

Read the user’s manual of each device carefully before wiring.

* Devices that can be connected to Ethernet

PC

2-13

PR300 with
Ethernet
communication
function

HUB

Data transmission

and reception

Ethernet

Ethernet Port of PR300

The PR300 can detect 10BASE-T or
100BASE-TX automatically. The LEDs of
Ethernet port show its status.

Link LED (upper side)
Color
Off
Amber
Green
Activity LED (lower side)
Color
Off
Amber
Green

Meaning
No Link
10 Mbps
100 Mbps

Meaning
No Activity
Half-duplex
Full-duplex

IM 77C01E01-10E

<Toc> <Ind> <2. Setup>

2.3.3 Wiring for RS-485 Communication for Ethernet-Serial Gateway Function

To use the Ethernet-serial gateway function, connect other RS-485 serial communication
device to the RS-485 communication terminals .

WARNING

To avoid an electric shock, be sure to turn off the power supply source to the equipment
involved before you start wiring.

The figure below shows the example of wiring connection for the PR300 with Ethernet
communication function. If other devices are used for connection, the names of communi­cation terminals and others may be different from those mentioned in the figure.

Read the user’s manual of each device carefully before wiring.

PC

2-14

(with Ethernet

communication function)

Terminator (built-in)

120Ω 1/4W

Wthen terminating on
wiring, short-circuit
terminals 17 and 18 .

Ethernet

PR300

PR300

(with RS-485

17 17

Aⴚ

18

Bⴙ

19

SG

Communication

cable

communication function)

18

19

2020

JIS Class D (3) grounding

(grounding resistance

of 100Ω or less)

Communication

cable

PR300

(with RS-485

communication function)

Aⴚ

Bⴙ

SG

Terminator (built-in)

18

19

20

120Ω 1/4W

Wthen terminating on
wiring, short-circuit
terminals 17 and 18 .

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3-1

3. Procedures for Setting PR300 Functions

To set the functions of the PR300, use the protocols described in Chapter 4, “PC
Link Communication Protocol,” Chapter 5, “Modobus/RTU and ASCII Communica­tion Protocols,” or Chapter 6, “Modbus/TCP Communication Protocol” according to
the instructions in this chapter.

For details of each function, refer to the PR300 Power and Energy Meter User’s
Manual (electronic manual).

For how to read the tables in this chapter, refer to Chapter 7, “Functions and Usage
of D Registers.”

The PR300 offers registers for floating-point data. To perform settings via communi­cation from higher-level device, floating-point data is displayed by IEEE754 (single
precision).

NOTE

• The PR300 has data (D register) the unit of which is two words. When 2-word data
need to be written or read, writing or reading operations must be performed for the 2­word data at the same time.

• Even if data written to the D register is out of the effective range, a normal response is
returned. The part of the written data within the effective range becomes effective on
the PR300 when the equivalent setting change status is written for that data.

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.1 Basic Setting

3.1.1 Setting of VT Ratio

[Procedure]

(1) Write a VT ratio to the two D registers in the table below. The data type is 4-byte

floating point.

(2) After writing that value, write 1 to the setup change status register, D0207.

3-2

D Register

D0201
D0202

D0207

Initial value of VT ratio: 1 (4-byte floating-point data: 3F800000)

Reference No.

40201
40202

40207

H No.

00C8
00C9

00CE

VT ratio (float, lower 2 bytes)
VT ratio (float, upper 2 bytes)
Setup change status

(D0201 to D0206 are validated)

Description

Effective Range

1 to 6000

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the VT ratio to 10:
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:
If 10 is converted into a 4-byte floating-point value, the value is 4120 0000.

[Command]
[STX] 01010WRW03D0201, 0000, D0202, 4120, D0207, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]

NOTE

• When changing the VT ratio, the integrated values of active energy, reactive energy,
apparent energy, optional active energy, and regenerative energy will return to “0.”
The values of the demand alarm point and the scaling of analog output will also be
initialized.

• Set the VT and CT ratios so that [secondary rated power] × [VT ratio] × [CT ratio] is
smaller than 10 GW. When this value is 10 GW or greater, writing to D registers will be
invalid (no error is output).

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.1.2 Setting of CT Ratio

[Procedure]

(1) Write a CT ratio to the two D registers in the table below. The data type is 4-byte

floating point.

(2) After writing that value, write 1 to the setup change status register, D0207.

3-3

D Register

D0203
D0204

D0207

Initial value of CT ratio: 1 (4-byte floating-point data: 3F800000)

Reference No.

40203
40204

40207

H No.

00CA
00CB

00CE

CT ratio (float, lower 2 bytes)
CT ratio (float, upper 2 bytes)
Setup change status

(D0201 to D0206 are validated)

Description

Effective Range

0.05 to 32000

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the CT ratio to 10.0:
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:
If 10.0 is converted into a 4-byte floating-point value, the value is 4120 0000.

[Command]
[STX] 01010WRW03D0203, 0000, D0204, 4120, D0207, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]

NOTE

• When changing the CT ratio, the integrated values of active energy, reactive energy,
apparent energy, optional active energy, and regenerative energy will return to “0.”
The values of the demand alarm point and the scaling of analog output will also be
initialized.

• Set the VT and CT ratios so that [secondary rated power] × [VT ratio] × [CT ratio] is
smaller than 10 GW. When this value is 10 GW or greater, writing to D registers will be
invalid (no error is output).

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.1.3 Setting of Integrated Low-cut Power

[Procedure]

(1) Write an integrated low-cut power value to the two D registers in the table below. The

data type is 4-byte floating point.

(2) After writing that value, write 1 to the setup change status register, D0207.

3-4

D Register

D0205

D0206

D0207

Initial value of integrated low-cut power: 0.05% (4-byte floating-point data: 3D4CCCCD)

Reference No.

40205

40206

40207

H No.

00CC

00CD

00CE

Description

Integrated low-cut power
(float, lower 2 bytes)

Integrated low-cut power
(float, upper 2 bytes)

Setup change status
(D0201 to D0206 are validated)

Effective Range

0.05 to 20.00
Unit: %

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the integrated low-cut power value to 10.0%:
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:
If 10.0 is converted into a 4-byte floating-point value, the value is 4120 0000.

[Command]
[STX] 01010WRW03D0205, 0000, D0206, 4120, D0207, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.2 Setting Pulse Output

3.2.1 Selection of Measurement Item for Pulse Output

[Procedure]

(1) Write a measurement item for pulse output value to the D register in the table below.

The data type is integer.

(2) After writing that value, write 1 to the pulse output writing status register, D0211.

3-5

D Register

D0208

D0211

Initial value of measurement item for pulse output: 0 (active energy)

Reference No.

40208

40211

H No.

00CF

00D2

Description

Measurement item for
pulse output

Pulse output writing status
(D0208, D0209, and D0210
are validated)

Effective Range

0: Active energy
1: Regenerative energy
2: LEAD reactive energy
3: LAG reactive energy
4: Apparent energy

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the measurement item for pulse output to 1 (LEAD reactive energy):
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:

[Command]
[STX] 01010WRW02D0208, 0001, D0211, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]

NOTE

• A measurement item for pulse output value can be set for the PR300 with pulse
output.

• When the PR300 is the three-phase four-wire system (2.5 element), the following
measurement items can be measured only when the current is in a state of equilib­rium:
“2: LEAD reactive energy”, “3: LAG reactive energy” and “4: Apparent energy.”

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.2.2 Pulse Unit

[Procedure]

(1) Write a pulse unit value to the D register in the table below. The data type is integer.
(2) After writing that value, write 1 to the pulse output writing status register, D0211.

3-6

D Register

D0209

D0211

Initial value of pulse unit: 10 (1000 Wh/pulse)

Reference No.

40209

40211

H No.

00D0

00D2

Description

Pulse unit

Pulse output writing status
(D0208, D0209, and D0210
are validated)

Effective Range

1 to 50,000
Unit:  100 Wh/pulse

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the pulse unit to 100 Wh/pulse, write “0001.”
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:

[Command]
[STX]01010WRW02D0209,0001,D0211,0001[ETX][CR]
[Response]
[STX]0101OK[ETX][CR]

NOTE

• A pulse unit value can be set for the PR300 with pulse output.

• To set the pulse unit value via communication, set it to 1/100 the value of the displayed

(true) value (e.g., set it to 5 when setting the pulse unit value to 500 Wh/pulse).

IM 77C01E01-10E

<Toc> <Ind> <3. Procedures for Setting PR300 Functions>

3.2.3 ON Pulse Width

(1) Write an ON pulse width value to the D register in the table below. The data type is

integer.

(2) After writing that value, write 1 to the pulse output writing status register, D0211.

NOTE

When the value to be set for the ON pulse width is greater than the value calculated by the
following equation, the value cannot be set:

3-7

ON pulse width (ms) 

D Register

D0210

D0211

Initial value of ON pulse width: 5 (50 ms)

Reference No.

40210

40211

Secondary rated power [W]  VT ratio  CT ratio  1.2  2

00D1

00D2

H No.

Pulse unit [Wh/pls]  60  60  1000

Description

ON pulse width

Pulse output writing status
(D0208, D0209, and D0210
are validated)

Effective Range

1 to 127
Unit:  10 ms

If other than 1: Invalid
If 1: Writing is executed

[Example]

To set the ON pulse width to 100 ms, write “000A.”
For station number 01, use PC link communication (without checksum) and the random

write command as shown below:

[Command]
[STX] 01010WRW02D0210, 000A, D0211, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]

NOTE

• An ON pulse width value can be set for the PR300 with pulse output.

• To set the ON pulse width value via communication, set it to 1/10 the value of the

displayed (true) value (e.g., set it to 5 when setting the ON pulse width value to 50
ms).

IM 77C01E01-10E