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
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
<Toc> <Ind> <Rev>
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
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.”
2.1Setup 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.
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
2.1.1Procedure 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)
”
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
2.1.2Procedure 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.
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
2.1.3Procedure 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)
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
2.2Setting 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).
2.2.1Conditions 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
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
● 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.
IM 77C01E01-10E
<Toc> <Ind><2. Setup>
2.2.2Conditions 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
IM 77C01E01-10E
<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 addressIP-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 MaskSM-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 GatewayDG-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>
2.2.3Conditions 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
MenuSetting 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
MenuSetting 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>
2.3Wiring for Communication
Connect a higher-level device with the PR300 for using the communication functions. The wiring procedures and precautionary notes are as follows.
2.3.1Wiring 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>
2.3.2Wiring 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>
2.3.3Wiring 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
1717
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>
3.1Basic Setting
3.1.1Setting 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.
•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>
3.1.2Setting 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.
•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>
3.1.3Setting 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.
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.2Setting Pulse Output
3.2.1Selection 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
•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>
3.2.2Pulse 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
•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
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.3Setting Analog Output
3.3.1Selection of Measurement Item for Analog Output
[Procedure]
(1)Write a measurement item for analog output value to the D register in the table below.
The data type is integer.
(2)After writing that value, write 1 to the analog output writing status register, D0217.
3-8
D Register
D0212
D0217
Initial value of measurement item for analog output: 0 (active power)
Reference No.
40212
40217
H No.
00D3
00D8
Description
Measurement item for
analog output
Analog output writing status
(D0212 to D0216 are
validated)
Effective Range
0: Active power
1: Reactive power
2: Apparent power
3: Voltage-1
4: Voltage-2
5: Voltage-3
6: Current-1
7: Current-2
8: Current-3
9: Power factor
10: Frequency
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the measurement item for analog output to 3 (voltage-1):
For station number 01, use PC link communication (without checksum) and the random
•A measurement item for analog output value can be set for the PR300 with analog
output.
•Different types of the PR300 can measure different items, and so the values that can
be set to the D register differ depending on the PR300 type. If a value that cannot be
written to the D register is written, it will be invalid. The table below shows the values
that cannot be set for four types of the PR300:
Phase and Wire System
Single-phase two-wire
Single-phase three-wire
Three-phase three-wire
Three-phase four-wire (2.5 element)
4: Voltage-2, 5: Voltage-3, 7: Current-2, and 8: Current-3
5: Voltage-3 and 8: Current-3
4: Voltage-2 and 7: Current-2
4: Voltage-2 and 7: Current-2
•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: “1: Reactive power”, “2: Apparent power”, “6: Current-1”, “8: Current-3” and “9:
Power factor.”
Values that cannot be Set
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.3.2Upper/Lower Limits of Scaling
[Procedure]
(1)Write upper/lower limits of scaling value to the four D registers in the table below. The
data type is 4-byte floating point.
(2)After writing that value, write 1 to the analog output writing status register, D0217.
3-9
D Register
D0213
D0214
D0215
D0216
D0217
Initial value of lower limit of scaling: 50%
Initial value of upper limit of scaling: 100%
Reference No.
40213
4021400D5
4021500D6
4021600D7
40217
H No.
00D4
00D8
Description
Lower limit of scaling
(float, lower 2 bytes)
Lower limit of scaling
(float, upper 2 bytes)
Upper limit of scaling
(float, lower 2 bytes)
Upper limit of scaling
(float, upper 2 bytes)
Analog output writing status
(D0212 to D0216 are
validated)
Effective Range
0.0 to 50.0
Unit: %
50.0 to 100.0
Unit: %
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the lower limit of scaling 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.
•A demand alarm release function value can be set for the PR300 with demand measuring function.
•When the demand alarm release function is used by digital input, releasing via communication is not possible.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.5Communication Setting
3.5.1Protocol
[Procedure]
(1)Write a protocol value to the D register in the table below. The data type is integer.
(2)After writing that value, write 1 to the RS-485 writing status register, D0277.
3-16
D Register
D0271
D0277
Initial value of protocol: 1 (PC link with checksum)
*1: Modbus/TCP can be selected for the PR300 with Ethernet communication function only.
Reference No.
40271
40277
H No.
010E
0114
Description
Protocol
RS-485 writing status
(D0271 to D0276 are
validated)
Effective Range
0: PC link
(without checksum)
1: PC link
(with checksum)
2: Modbus/ASCII
3: Modbus/RTU
4: Modbus/TCP *
5: PR201 original
If other than 1: Invalid
If 1: Writing is executed
1
NOTE
•When Modbus/TCP is selected for the protocol, the baud rate, the stop bit, the data
length and the station number are fixed and unchangeable.
•When PR201 original is selected, the baud rate, the parity, the stop bit and the data
length cannot be set via communication.
[Example]
To set the protocol to 4 (Modbus/TCP):
For station number 01, use PC link communication (without checksum) and the random
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.5.2Baud Rate
[Procedure]
(1)Write a baud rate value to the D register in the table below. The data type is integer.
(2)After writing that value, write 1 to the RS-485 writing status register, D0277.
3-17
D Register
D0272
D0277
Initial value of baud rate: 1 (9600 bps)
Reference No.
40272
40277
H No.
010F
0114
Description
Baud rate
RS-485 writing status
(D0271 to D0276 are
validated)
Effective Range
0: 2400 bps
1: 9600 bps
2: 19200 bps
If other than 1: Invalid
If 1: Writing is executed
NOTE
When Modbus/TCP is selected for the protocol, the baud rate is fixed and unchangeable at
9600 bps.
[Example]
To set the baud rate to 2 (19200 bps):
For station number 01, use PC link communication (without checksum) and the random
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.5.3Parity
[Procedure]
(1)To set the parity, write data to the D register in the table below. The data type is integer.
(2)After writing that value, write 1 to the RS-485 writing status register, D0277.
3-18
D Register
D0273
D0277
Initial value of parity: 0 (NONE)
Reference No.
40273
40277
H No.
0110
0114
Description
Parity
RS-485 writing status
(D0271 to D0276 are
validated)
Effective Range
0: NONE
1: EVEN
2: ODD
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the parity to 1 (EVEN):
For station number 01, use PC link communication (without checksum) and the random
The set regenerative energy value range of the PR300 changes depending on the values
of the VT and CT ratios. The table below shows the set value range.
[Secondary Rated Power] [VT Ratio] [CT Ratio]
Less than 100 kW
100 kW to less than 1 MW
1 MW to less than 10 MW
10 MW or greater
Possible Set Value Range
0 to 99999 kWh
0 to 999999 kWh
0 to 9999999 kWh
0 to 99999999 kWh
NOTE
The secondary rated power of the PR300 changes depending on its model and suffix
codes.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.6.3LEAD Reactive Energy
[Procedure]
(1)Write a LEAD reactive energy value to the two D registers in the table below. The data
type is integer.
(2)After writing that value, write 1 to the writing status register, D0381.
3-28
D Register
D0377
D0378403780179
D038140381017C
Reference No.
40377
H No.
0178
Description
LEAD reactive energy-setpoint
(lower 2 bytes)
LEAD reactive energy-setpoint
(upper 2 bytes)
Reactive energy writing status
(D0377 to D0380 are validated)
Effective Range
Refer to the "NOTE" below.
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the LEAD reactive energy value to 10,000,000 kVarh:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
If 10,000,000 is converted into a hexadecimal value, the value is 0098 9680. Then the
order of the upper two bytes and the lower two bytes is reversed ⇒ 9680 0098.
The set LEAD reactive energy value range of the PR300 changes depending on the values
of the VT and CT ratios. The table below shows the set value range.
[Secondary Rated Power] [VT Ratio] [CT Ratio]
Less than 100 kW
100 kW to less than 1 MW
1 MW to less than 10 MW
10 MW or greater
Possible Set Value Range
0 to 99999 kvarh
0 to 999999 kvarh
0 to 9999999 kvarh
0 to 99999999 kvarh
NOTE
The secondary rated power of the PR300 changes depending on its model and suffix codes.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.6.4LAG Reactive Energy
[Procedure]
(1)Write a LAG reactive energy value to the two D registers in the table below. The data
type is integer.
(2)After writing that value, write 1 to the writing status register, D0381.
3-29
D Register
D0379
D038040380017B
D038140381017C
Reference No.
40379
H No.
017A
Description
LAG reactive energy-setpoint
(lower 2 bytes)
LAG reactive energy-setpoint
(upper 2 bytes)
Reactive energy writing status
(D0377 to D0380 are validated)
Effective Range
Refer to the "NOTE" below.
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the LAG reactive energy value to 10,000,000 kVarh:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
If 10,000,000 is converted into a hexadecimal value, the value is 0098 9680. Then the
order of the upper two bytes and the lower two bytes is reversed ⇒ 9680 0098.
The set LAG reactive energy value range of the PR300 changes depending on the values
of the VT and CT ratios. The table below shows the set value range.
[Secondary Rated Power] [VT Ratio] [CT Ratio]
Less than 100 kW
100 kW to less than 1 MW
1 MW to less than 10 MW
10 MW or greater
Possible Set Value Range
0 to 99999 kvarh
0 to 999999 kvarh
0 to 9999999 kvarh
0 to 99999999 kvarh
NOTE
The secondary rated power of the PR300 changes depending on its type.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.6.5Apparent Energy
[Procedure]
(1)Write an apparent energy value to the two D registers in the table below. The data
type is integer.
(2)After writing that value, write 1 to the writing status register, D0384.
3-30
D Register
D0382
D038340383017E
D038440384017F
Reference No.
40382
H No.
017D
Description
Apparent energy-setpoint
(lower 2 bytes)
Apparent energy-setpoint
(upper 2 bytes)
Apparent energy writing status
Effective Range
Refer to the "NOTE" below.
If other than 1: Invalid
If 1: Writing is executed
[Example]
To set the apparent energy value to 10,000,000 kVAh:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
If 10,000,000 is converted into a hexadecimal value, the value is 0098 9680. Then the
order of the upper two bytes and the lower two bytes is reversed ⇒ 9680 0098.
The set apparent energy value range of the PR300 changes depending on the values of
the VT and CT ratios. The table below shows the set value range.
[Secondary Rated Power] [VT Ratio] [CT Ratio]
Less than 100 kW
100 kW to less than 1 MW
1 MW to less than 10 MW
10 MW or greater
Possible Set Value Range
0 to 99999 kVAh
0 to 999999 kVAh
0 to 9999999 kVAh
0 to 99999999 kVAh
NOTE
The secondary rated power of the PR300 changes depending on its model and suffix
codes.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.7Executing Reset Operations
3.7.1Remote Reset
[Procedure]
(1)To execute remote reset, write data to the D register in the table below. The data type
is integer.
3-31
D Register
D0400
Initial value of remote reset: 0
Reference No.
40400
H No.
018F
Description
Remote reset
Effective Range
If other than 1: Invalid
If 1: PR300 reset
NOTE
•When remote reset is executed, maximum, minimum and instantaneous voltage
values and maximum and instantaneous current values will be reset. Optional integration is terminated if it is being performed.
•Even when remote reset is executed, active energy, reactive energy, and apparent
energy data as well as set parameter values are retained.
[Example]
To execute remote reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX] 01010WRW01D0400, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]
NOTE
After remote reset is executed, wait for 10 seconds or more before sending another command. It takes about 10 seconds to reset.
Even when PR300 was reset by power supply switch off/on, also wait for 10 seconds or
more before sending another command.
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.7.2Maximum/Minimum Values Reset
[Procedure]
(1)To execute maximum/minimum values reset, write data to the D register in the table
below. The data type is integer.
3-32
D Register
D0351
Reference No.
40351
H No.
015E
[Example]
To execute maximum/minimum values reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX]01010WRW01D0351,0001[ETX][CR]
[Response]
[STX]0101OK[ETX][CR]
3.7.3Energy Value All-Reset
[Procedure]
Description
Maximum/minimum values
(D0101 to D0138) reset
Effective Range
If other than 1: Invalid
If 1: Maximum/minimum
values reset
(1)To execute energy value all-reset, write data to the D register in the table below. The
data type is integer.
D Register
D0352
Reference No.
40352
H No.
015F
Description
Energy value all-reset
Relevant items are as follows:
Active energy (D0001, D0002)
Regenerative energy (D0003, D0004)
LEAD reactive energy (D0005, D0006)
LAG reactive energy (D0007, D0008)
Apparent energy (D0009, D0010)
If other than 1: Invalid
If 1: Energy value all-reset
Effective Range
[Example]
To execute energy value all-reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX]01010WRW01D0352,0001[ETX][CR]
[Response]
[STX]0101OK[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.7.4Active Energy Reset
[Procedure]
(1)To execute active energy reset, write data to the D register in the table below. The
data type is integer.
3-33
D Register
D0353
Reference No.
40353
H No.
0160
Active energy
(D0001 and D0002) reset
[Example]
To execute active energy reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX] 01010WRW01D0353, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]
3.7.5Regenerative Energy Reset
[Procedure]
(1)To execute regenerative energy reset, write data to the D register in the table below.
The data type is integer.
Description
Effective Range
If other than 1: Invalid
If 1: Active energy reset
D Register
D0354
Reference No.
40354
H No.
0161
Description
Regenerative energy
(D0003 and D0004) reset
Effective Range
If other than 1: Invalid
If 1: Regenerative energy
reset
[Example]
To execute regenerative energy reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX] 01010WRW01D0354, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.7.6Reactive Energy Reset
[Procedure]
(1)To execute reactive energy reset, write data to the D register in the table below. The
data type is integer.
3-34
D Register
D0355
Reference No.
40355
H No.
0162
[Example]
To execute reactive energy reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX] 01010WRW01D0355, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]
3.7.7Apparent Energy Reset
[Procedure]
Description
Reactive energy
(D0005 to D0008) reset
Effective Range
If other than 1: Invalid
If 1: Reactive energy
reset
(1)To execute apparent energy reset, write data to the D register in the table below. The
data type is integer.
D Register
D0356
Reference No.
40356
H No.
0163
Description
Apparent energy
(D0009 and D0010) reset
Effective Range
If other than 1: Invalid
If 1: Apparent energy reset
[Example]
To execute apparent energy reset:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX] 01010WRW01D0356, 0001 [ETX] [CR]
[Response]
[STX] 0101OK [ETX] [CR]
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.8Setting Control States
3.8.1 Integration Start/Stop
[Procedure]
(1)To execute integration start/stop, write data to the D register in the table below. The
data type is integer.
3-35
D Register
D0301
Initial value of integration start/stop: 1 (start)
Reference No.
40301
H No.
012C
Description
Integration start/stop
Relevant items are as follows:
Active energy (D0001, D0002)
Regenerative energy (D0003, D0004)
LEAD reactive energy (D0005, D0006)
LAG reactive energy (D0007, D0008)
Apparent energy (D0009, D0010)
0: Stop
1: Start
Effective Range
[Example]
To execute integration start/stop:
For station number 01, use PC link communication (without checksum) and the random
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.8.2Optional Integration Start/Stop
[Procedure]
(1)To execute optional integration start/stop, write data to the D register in the table
below. The data type is integer.
3-36
D Register
D0302
Initial value of optional integration start/stop: 0 (stop)
Reference No.
40302
H No.
012D
Description
Optional integration start/stop
Relevant D registers:
D0011 to D0014
Effective Range
0: Stop
1: Start
NOTE
Optional integration start/stop can also be controlled by digital input. Once digital input is
performed, it is the only means for such control. Control via communication is no longer
possible until the power is turned off or remote reset is executed (see subsection 3.7.1).
However, for the PR300 with demand measuring function, digital input is used to release
the demand alarm. In this case, optional integration start/stop cannot be used.
[Control via communication]
START commandSTOP command
Digital input turned onDigital input turned offData update
Perform integration for this duration
Time
No response to
digital input requests
[Control by digital input]
Digital input turned onDigital input turned off
START
command
Perform integration for this duration
STOP
command
No response to requests
via communication
Time
Data update
[Example]
To execute optional integration start/stop:
For station number 01, use PC link communication (without checksum) and the random
write command as shown below:
[Command]
[STX]01010WRW01D0302,0001[ETX][CR]
[Response]
[STX]0101OK[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><3. Procedures for Setting PR300 Functions>
3.8.3Demand Measurement Start/Stop
[Procedure]
(1)To execute demand measurement start/stop, write data to the D register in the table
below. The data type is integer.
3-37
D Register
D0311
Initial value of demand measurement start/stop: 0 (measurement stop)
Reference No.
40311
H No.
0136
Description
Demand measurement start/stop
Relevant items are as follows:
Demand power (D0043, D0044)
Demand current (D0045 to D0050)
Effective Range
0: Measurement stop
1: Measurement start
NOTE
Demand measurement start/stop can also be controlled by operation key. Once the operation key is used, it is the only means for such control. Control via communication is not
possible until the power is turned off, or remote reset is executed (see subsection 3.7.1).
[Control via communication]
START commandSTOP command
Turned on by operation keyTurned off by operation key
[Control by operation key]
Turned on by operation keyTurned off by operation key
Perform integration for this duration
Time
Data update
No response to requests
by operation key
Perform integration for this duration
Time
START
command
STOP
command
Data update
No response to requests
via communication
[Example]
To execute demand measurement start/stop:
For station number 01, use PC link communication (without checksum) and the random
Confirmation and release of demand alarm state can be set for the PR300 with demand
measuring function.
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.PC Link Communication Protocol
4.1Overview
The use of PC link communication enables the PR300 to communicate with a device
such as a PC or FA-M3(PLC)'s UT link module. Such a device can be used in communication to read/write data from/to D registers which are internal registers of the
PR300.
PLC
FA-M3
Model of UT link module: F3LC51-2N
RS-485 communication
Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31
4-1
Figure 4.1 Example of Connection for PC Link Communication
Hereafter, PCs are generically called “higher-level devices.”
In PC link communication, a higher-level device identifies each PR300 with a station
number of 01 to 99.
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 setup change status is written for that data.
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.1.1Configuration of Command
Commands sent from a higher-level device to the PR300 consist of the following elements.
4-2
Number
of Bytes
ElementSTXStation
12 2132 11
number
(ST-NO)
(1)(2)(3)(4)(5)(7)(8)(9)(6)
CPU
number
01
Time to wait
for response
0
CommandData
Variable length
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)Station Number (01 to 99)
Station numbers are used by the higher-level device to identify the PR300 at the
communication destination. (These numbers are identification numbers specific to
individual PR300.) P1: Broadcasting mode (See subsection 4.1.4, “Specifying Broadcast")
(3)CPU number
This number is fixed to ‘01.’ The ASCII codes are 30 and 31 in hexadecimal.
(4)Time to Wait for Response
This is fixed to ‘0’. The ASCII code is 30 in hexadecimal.
(5)Command (See section 4.2, “Command and Response”)
Specify a command to be issued from the higher-level device.
ChecksumETXCR
(6)Data Corresponding to Command
Specify an internal register (D register), number of data pieces, and others.
(7)Checksum
This is required if the protocol with checksum is selected for the RS-485 communication protocol parameter COMM.
It 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 required only for PC link communication with checksum. PC link
communication without checksum does not require this 2-byte space of ASCII code.
[Example]
[STX]01010WRDD0001, 02䊐䊐 [ETX][CR]
Add up the hexadecimal values of the ASCII codes of each text.
Lowermost two digits of the added results as the checksum.
[STX]01010WRDD0001,0272[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
(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.
NOTE
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.
4.1.2Configuration of Response
Responses from the PR300 with respect to a command sent from the higher-level device
consist of the elements shown below, which differ depending on the condition of communication; normal or failure.
4-3
1) Normal Communication
When communication completes normally, the PR300 returns a character string “OK” and
data corresponding to a command.
No parameter data area for write command.
Number
of Bytes
ElementSTXStation
number
(ST-NO)
CPU
number
01
Variable length12 22211
OKParameter dataChecksumETXCR
2) In the Event of Failure
If communication does not complete normally, the PR300 returns a character string “ER”
and error code (EC1 and EC2). (See subsection 4.1.3, “Response Error Codes”.)
•No response is made in case of an error in station number specification or CPU
number specification.
•If a PR300 cannot receive ETX in a command, response may not be made.
Note: As a countermeasure, provide a timeout process in the communication functions of the higher-level device or in
communication programs.
Number
of Bytes
ElementSTXEREC1EC2Command ChecksumETX CRStation
12 22223 211
CPU
number
(ST-NO)
number
01
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.1.3Response Error Codes
See Also
4.1.2, “Configuration of Response”, for the configuration of response in the event of error.
The error codes (EC1) and detailed error codes (EC2) of responses are as follows.
Table 4.1 List of Error Codes EC1
Error
Code
Command error
02
Register specification error
03
Out of setpoint range
04
(when in writing operation)
Out of data count range
05
Monitor error
06
Parameter error
08
Checksum error
42
Internal buffer overflow
43
44• The end-of-data or end-of-text character has not been received.
Character reception timeout
MeaningCause(s)
• No command exists.
• Command not executable
• No register number exists.
•
A value other than hexadecimal values (0 to 9, A to F) has been specified in word
specification.
• The position of a start for a data load/save or other command is out of the
address range.
• The specification of the number of words is out of the specified range.
• An attempt was made to execute monitoring without specifying the monitor
(WRS).
• An illegal parameter is set.
• The sum does not match the expected value.
• A data value greater than the specified was received.
4-4
Table 4.2 List of Detailed Error Codes EC2
Meaning
03
04
05
08Parameter error
Register specification error
Out of setpoint range
Out of data count range
Parameter number where error occurred (HEX)
This is the sequence number of a parameter that first resulted
in an error when counted from the leading parameter.
e.g.:
[STX]01010WRW02D0043,3F80,A0044,0000[ETX][CR]
Parameter numbers 1 2 3 4 5
[STX]0101ER0304WRW[ETX][CR]
In this case, EC1=03 and EC2=04.
Detailed Error Code (EC2)Error Code (EC1)
Register name specification error
↓
For error codes other than those noted as EC1, there is no EC2 meaning, and 0x00 is
returned as a response.
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.1.4Specifying Broadcast
The corresponding multiple PR300 perform the function to receive and process a command in which this station number is specified.
(1)Specify “P1” for the station number in the command to execute it.
(2)This command works independently of station numbers of slave stations (01 to 99).
(3)This command is applicable for writing only.
(4)No response is returned from the PR300 when communication is performed using this
command.
4-5
PC
RS-485 communication
Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31
Figure 4.2 Broadcasting
Broadcast data.
* No response from slave stations
[Example of Starting Optional Integrations]
Use PC link communication (without checksum) and the random write command as shown
below:
[STX]P1010WRW01D0302,0000[ETX][CR]
D Register
D0302
Reference No.
40302
H No.
012D
Description
Optional integration start/stop
(D0011 to D0014)
Effective Range
0: Stop
1: Start
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.2Command and Response
The following shows the lists of commands available in PC link communication. The
details of them are explained in the description of each command.
(1)Word-basis Access Commands
4-6
CommandDescription
WRD
WWR
WRR
WRW
WRS
WRM
Word-basis read
Word-basis write
Word-basis, random read
Word-basis, random write
Specifies D registers to be monitored on a
word-by-word basis.
Word-basis monitoring
(2)Information Commands
CommandDescription
INF6
INF7
Reads model, suffix codes, and version.
Reads the maximum value of CPU.
Number of words to be handled
1 to 64 words
1 to 64 words
1 to 32 words
1 to 32 words
1 to 32 words
—
Number of units to be handled
1
1
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
WRDReads D registers on a word-by-word basis
● Function
This function code reads a sequence of contiguous register information on a word-by-word
basis by the specified number of words, starting with a specified register number.
•The number of words to be read at a time is 1 to 64.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
4-7
Number of
Bytes
Command
element
Number of
Bytes
Response
element
1
STX2Station
number
(ST-NO)
1
STX
2
Station
number
(ST-NO)
01
01
2
1
3
0
WRD
2
OK
4
2
dddd14dddd2
5
Register
number
1
Comma
or
space
…
…
2
Number
of words
(n)
4
ddddn
2
Checksum
2
Checksum1ETX1CR
1
ETX1CR
The response is returned in a 4-digit character string (0000 to FFFF) in hexadecimal.
ddddn: read data of the specified number of words
ddddn = character string in hexadecimal
n = 1 to 64 words
● Example
Read the active energy (register symbol: kWh L and kWh H) of the PR300 at station number 01.
The register numbers for active energy are D0001 and D0002.
[Command]
[STX]01010WRDD0001, 0272 [ETX] [CR]
The data of active energy (2 words) will be returned in response to the command above.
[Response]
[STX]0101OK7840017D0B [ETX] [CR]
Note: To use the response data as the reading, reverse the order of the upper and lower words.
WWRWrites data into D registers on a word-by-word basis
● Function
This function code writes information into a sequence of contiguous registers on a word-byword basis by the specified number of words, starting with a specified register number.
•The number of words to be written at a time is 1 to 64.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
4-8
Number
of Bytes
Command
element
Command (continued)
4
dddd2
STX
…
…
1
2
Station
number
(ST-NO)
4
ddddn
2
01
2
Checksum1ETX1CR
3
1
0
WWR
5
Register
number
1
Comma
or space
2
Number
of words
(n)
1
Comma
or space
Write information is specified in a 4-digit character string (0000 to FFFF) in
hexadecimal.
ddddn: write data of the specified number of words
ddddn = character string in hexadecimal
n = 1 to 64 words
Number
of Bytes
Response
element
1
STX
2
Station
number
(ST-NO)
2
012OK
2
Checksum1ETX1CR
4
dddd1
● Example
Write the floating point data “00004120” into the VT ratio (register symbol: VT L and VT H)
and CT ratio (register symbol: CT L and CT H) of the PR300 at station number 01.
The register numbers for VT ratio are D0201 and D0202.
The register numbers for CT ratio are D0203 and D0204.
[Command]
[STX]01010WWRD0201,04,0000412000004120C3[ETX][CR]
“OK” will be returned in response to the command above.
[Response]
[STX]0101OK5C[ETX][CR]
Note: To use the response data as the reading, reverse the order of the upper and lower words.
WRRReads D registers on a word-by-word basis in random order
● Function
This function code reads the statuses of the individual registers, on a word-by-word basis,
specified in a random order by the specified number of words.
•The number of words to be read at a time is 1 to 32.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
4-9
Number
of Bytes
Command
element
Command (continued)
…
…
Number
of Bytes
Response
element
1
STX2Station
5
Register
number
n
1
STX2Station
number
(ST-NO)
2
Checksum
number
(ST-NO)
2
01
1
ETX1CR
2
01
1
0
WRR
2
OK
dddd14dddd2
3
4
2
Number
of words
(n)
5
Register
number
1
…
…
Comma
space
4
ddddn
1
or
2
Checksum
5
Register
number
2
The response is returned in a 4-digit character string (0000 to FFFF) in hexadecimal.
ddddn: read data of the specified number of words
ddddn = character string in hexadecimal
n = 1 to 32 words
● Example
1
Comma
or
space
1
ETX1CR
Read the voltage-1 (register symbol: V1 L and V1 H) and current-1 (register symbol: A1 L
and A1 H) of the PR300 at station number 01.
The register numbers for voltage-1 are D0027 and D0028.
The register numbers for current-1 are D0033 and D0034.
Writes data into D registers on a word-by-word basis in random order
● Function
This function code writes register information specified for each register into the registers
specified in a random order by the specified number of words.
•The number of words to be written at a time is 1 to 32.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
Number
of Bytes
Command
element
Command (continued)
5
Register
number
2
1
STX2Station
1
Comma
or
space
number
(ST-NO)
4
dddd2
…
…
2
01
1
0
5
Register
number
n
3
WRW
Comma
or space
Number
of words
1
2
(n)
ddddn
5
Register
number
4
Checksum1ETX1CR
1
Comma
space
2
1
or
4
dddd1
1
Comma
or
space
Write information is specified in a 4-digit character string (0000 to FFFF) in hexadecimal.
ddddn: repetition of register numbers and write information of the specified number
of words
ddddn = character string in hexadecimal
n = 1 to 32 words
Number
of Bytes
Response
element
1
STX2Station
number
(ST-NO)
2
012OK
2
Checksum1ETX1CR
● Example
Write 1 into the remote reset (register symbol: RMT RST) and active energy reset (register
symbol: kWh RST) of the PR300 at station number 01.
The register number for remote reset is D0400.
The register number for active energy reset is D0353.
“OK” will be returned in response to the command above.
[Response]
[STX]0101OK5C[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4-11
WRSSpecifies the D registers to be monitored on a word-by-word basis
● Function
This function code specifies the register numbers to be monitored on a word-by-word
basis. Note that this command simply specifies the registers. Actual monitoring is performed by the WRM command after the register numbers are specified by this command.
If the volume of data is large and you wish to increase the communication rate, it is effective
to use a combination of the WRS and WRM commands rather than the WRR command. If
the power supply is turned off, the register numbers specified will be erased.
•The number of words to be specified at a time is 1 to 32.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
Number
of Bytes
Command
element
Command (continued)
…
…
Number
of Bytes
Response
element
1
STX2Station
5
Register
number
n
1
STX2Station
number
(ST-NO)
2
Checksum
number
(ST-NO)
2
01
1
ETX1CR
2
012OK
1
0
Checksum
3
WRS
Number
of words
2
2
(n)
1
ETX1CR
5
Register
number
1
1
Comma
or space
5
Register
number
2
● Example
Specify that the active power (register symbol: W L and W H) of the PR300 at station
number 01 is to be monitored. (This command simply specifies the registers.)
The register numbers for active power are D0021 and D0022.
[Command]
1
Comma
or space
[STX]01010WRS02D0021,D00228B[ETX][CR]
“OK” will be returned in response to the command above.
[Response]
[STX]0101OK5C[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
WRMMonitors the D registers on a word-by-word basis
● Function
This function code reads the information of the registers that have been specified in advance by the WRS command.
•Before executing this command, the WRS command must always be executed to
specify which registers are to be monitored. If no register has been specified, error
code 06 is returned.
•For the format of response in the event of failure, see subsection 4.1.2.
•The command shown below includes the checksum function. When performing
communication without the checksum, do not include the 2-byte checksum element in
the command.
● Command/Response (for normal operation)
4-12
Number
of Bytes
Command
element
Number
of Bytes
Response
element
1
STX2Station
number
(ST-NO)
1
STX2Station
number
(ST-NO)
01
01
2
2
1
0
WRM
2
dddd14dddd2
OK
3
4
2
Checksum1ETX1CR
…
…
ddddn
4
2
Checksum1ETX1CR
The response is returned in a 4-digit character string (0000 to FFFF) in hexadecimal.
ddddn: read data of the number of words specified by the WRS command
ddddn = character string in hexadecimal
n = 1 to 32 words
● Example
Monitor the active power (register symbol: W L and W H) of the PR300 at station number
01. (This command reads the status of the register specified by the WRS command.)
[Command]
[STX]01010WRME8[ETX][CR]
The data 2500 will be returned in response to the command above.
[Response]
[STX]0101OK4000451CF9[ETX][CR]
Note: To use the response data as the reading, reverse the order of the upper and lower words.
Active power: floating-point hex data 4000 451C→ (reversed) → Hex 451C 4000 ⇒ Decimal 2500
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
■ ■■ ■■
INF6Reads the model, suffix codes, and version information
● Function
This function code reads the model, suffix codes, and version number of the PR300.
•For the format of response in the event of failure, see subsection 4.1.2.
● Command/Response (for normal operation)
4-13
Number
of Bytes
Command
element
Number
of Bytes
Response
element
Response (continued)
4
Start
register
specified for
write
refreshing*
1
The * mark indicates fields the FA-M3’s UT link module refers to.
Note 1: Model and suffix code information
1
STX2Station
1
STX2Station
4
Number of
registers
specified for
write
refreshing*
0
2
01
number
(ST-NO)
2
012OK
number
(ST-NO)
2
Checksum1ETX1CR
3
11
0
INF26
Checksum1ETX
12
Model code:
PR300✩★
(Note 1)
Note 2: Version number and revision number
4
Version and
revision
numbers
(Note 2)
PR300–✩★䊐䊐䊐–䊐䊐
<Model>–<Suffix code>
Returns the currently selected phase and wire system
✩:
1: Single-phase two-wire system
2: Single-phase three-wire system
3: Three-phase three-wire system
4: Three-phase four-wire system
5: Three-phase four-wire system (2.5 element)
★: Returns the currently selected input range
1: 150 V/1 A
2: 150 V/5 A
3: 300 V/1 A
4: 300 V/5 A
5: 600 V/1 A
6: 600 V/5 A
(* ★ and ✩ are decided by the settings of the phase and wire system and the input range.)
䊐: Returns the suffix code as is
Example:
Suffix code: PR300-32333-6A-0;
Selected phase and wire system:
Single-phase three-wire system; and
Selected input range: 300 V/5 A; then
PR300243336A
Not returned
Example: 0102
(version number + revision number)
1
CR
4
Start
Number of
register
specified for
readout
refreshing*
<Revision number>
<Version number>
1
registers
specified for
readout
refreshing*
4
22
● Example
To read the model, suffix code etc. of PR300 at station number 01:
[Command]
[STX]01010INF605[ETX][CR]
In response to this command, the following values will be returned:
Phase and wire system: Single-phase three-wire system
Rated input voltage/current: 300 V/5 A AC
I/O function: Analog output and pulse output
Communication function: Ethernet
Optional measuring function: Demand measurement
Phase indication format: R, S, and T indications
This function code refurns the maximum value of CPU of a station in PC link communication.
•For the format of response in the event of failure, see subsection 4.1.2.
● Command/Response (for normal operation)
4-14
Number
of Bytes
Command
element
Number
of Bytes
Response
element
Note 1:The maximum value of CPU for power and energy meter is 1.
1
STX2Station
number
(ST-NO)
1
STX2Station
number
(ST-NO)
2
01
2
012OK
3
1
0
INF
maximum
value (Note1)
1
7
1
CPU
2
Checksum1ETX1CR
2
Checksum
1
ETX1CR
● Example
Read the maximum value of CPU number of the PR300 at station number 01.
[Command]
[STX]01010INF706[ETX][CR]
The data 1 will be returned in response to the command above.
[Response]
[STX]0101OK
18D[ETX][CR]
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.3Communication with Higher-level Devices
Higher-level devices are those capable of using the PC link communication protocol.
4.3.1Communication with FA-M3 (UT Link Module)
Communication with FA-M3 is achieved by simply connecting the PR300 to a UT link
module using the PC link communication protocol. Set the communication conditions of the PR300 identical to those of the UT link module.
PLC
FA-M3
Model of UT link module: F3LC51-2N
RS-485 communication
Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31
4-15
Figure 4.3 Communication with UT Link Module
The UT link module function has the following two modes, which allow you to communicate
with FA-M3 without being aware of it. For more information, see the optionally available
user's manual of UT Link Module (IM 34M6H25-01E).
1.Automatic mode
This mode enables the instruments' fixed devices (those that cannot be specified by
the user) to be constantly refreshed by reading from them. The fixed devices are
D0001 to D0022, and the read areas cannot be written to.
2.Manual mode
This mode enables the instrument's devices (those that can be specified by the user)
to be constantly refreshed by reading from and/or writing to them.
See Also
The devices mentioned here are D registers. For more information on D registers, see Chapter 7.
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
FA-M3's UT Link Module Setup Procedure (Example)
This section explains the procedure for setting up the FA-M3's UT link module when the
“Automatic mode” is used.
(1)Setting Up the UT Link Module
Before following the procedure, always make sure that the FA-M3's UT link module is
turned off. Then, open the inner cover and follow the setup steps described below.
Configure the DIP switch of the UT link module as shown below:
Switch No.StatusDescription
SW1
SW2, SW3
SW4
SW5
SW6
SW7
SW8
Set the Baud Rate switch to 9600 bps.
ON
ON
OFF
OFFChecksum: none
ONTermination character: yes (CR)
ONMode: Automatic mode
OFFNot used.
Data length: 8 bits
Parity: none (initial value: even)
Stop bit: 1 bit
4-16
Set the Communication Mode switch to 7 (Normal).
(2)Setting Up the PR300
Set the communication conditions of the PR300 as shown below:
For details on how to set the conditions, see the PR300 Power and Energy Meter Uuser's
Manual (electronic manual).
ParameterDescription
Communication protocol
Data length
Parity
Stop bit
Baud rate
PC link communication (without checksum)
8 bits
None
1 bit
9600 bps
(3)Turn on the FA-M3.
IM 77C01E01-10E
<Toc> <Ind><4. PC Link Communication Protocol>
4.4Sample Program
4.4.1Example of BASIC Program for Send and Receive
4-17
This section shows an example of a command sending and response receiving program
created with F-BASIC*
*1 PC/AT is the product of IBM Ltd.
*2 F-BASIC is the product of Fujitsu Ltd.
2
for PC/AT*1 (or compatible machines).
Example of the Program Created Using F-BASIC Version 6.3
Communication ConditionsBaud rate:9600bps
Parity:None
Data length: 8 bits
Stop bit:1 bit
Protocol:PC link (without checksum)
<Toc> <Ind><5. Modbus/RTU and ASCII Communication Protocols>
5-1
5.Modbus/RTU and ASCII Communication
Protocols
5.1Overview
The use of Modbus communication enables the PR300 to communicate with a
device such as a PC or PLC (sequencer). Such a device can be used in communication to read/write data from/to D registers which are internal registers of the PR300.
Hereafter, PCs are generically called “higher-level devices.”
Higher-level device
RS-485 communication
Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31
Figure 5.1 Example of Connection for Modbus Communication
See Also
Chapter 7 for information on the D registers.
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For Modbus communication with the PR300, we provide the ASCII mode and RTU mode
(binary system) for the transmission mode.
Table 5.1 ASCII and RTU Modes
ItemASCII ModeRTU Mode
Number of data bits7 bits (ASCII)8 bits (binary)
Message start mark
Message end mark
Message length
Data time intervals1 second or lessBetween frames: 3.5 characters
Error detection
*1:When message length in the RTU mode is assumed to be “N”, message length in ASCII mode is “2N+1”.
*2:LF is a synchronization character indicating that the PR300 is ready to accept the next signal. In the RTU mode,
synchronization is achieved during the time interval between characters. If there is a period of time equivalent to 3.5
characters before the next character is received, the message being received next is recognized as a new frame.
In Modbus communication, a higher-level device identifies each PR300 with a station
number of 01 to 99.
NOTE
5-2
•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.
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5.1.1Configuration of Message
Messages sent from the higher-level device to the PR300 consist of the following elements.
5-3
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Start of
Message Mark
None
1224n
(1)(3) (4)(5)(2)(6)
Station
Number
(ST-NO)
112n
Function
Code
DataError CheckEnd of
2
(variable)
22
(variable)
(1)Start of Message Mark
This mark indicates the start of a message. Note that only ASCII mode requires a
colon (:).
(2)Station Number (01 to 99)
Station numbers are used by the higher-level device to identify the PR300 at the
communication destination. (These numbers are identification numbers specific to
individual PR300, which are expressed in hexadecimal in the message.)
00: Broadcasting mode (See subsection 5.1.5, “Specifying Broadcast”)
(3)Function Code (See section 5.2, “Message and Response”)
This element specifies a command (function code) from the higher-level device.
Message Mark
None
(4)Data
This element specifies D register numbers, the number of D registers, parameter
values, or others in accordance with the function code. (It is expressed in hexadecimal
in the message.)
(5)Error Check
In RTU mode:Carried out by the cyclic redundancy check (CRC-16) system.
In ASCII mode:Carried out by the longitudinal redundancy check (LRC) system.
(6)End of Message Mark
This mark indicates the end of a message. Note that only ASCII mode requires CR +
LF.
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5.1.2Specifying D Registers
Specification of D registers using commercially available SCADA or other software
and specification of D registers for messages used in a customer-created communication program are different. Take note of this.
For a customer-created communication program, specify a value in hexadecimal that is
obtained by subtracting 40001 from a reference number.
Example: Specifying “D0043”
For messages in the customer-created communication program, specify “002A,” the
hexadecimal number of value 42 obtained by subtracting 40001 from the reference number.
5.1.3Checking Errors
Modbus communication has two modes, i.e., the ASCII mode which is communication
based on ASCII characters and the RTU mode which is binary code communication. These
modes use different error-checking methods.
5-4
■ ASCII Mode
In the ASCII mode, errors are checked by means of an LRC longitudinal redundancy
check.
The LRC value is the two's complement of the sum obtained by adding up data byte by
byte, from the station number to the last data item, excluding ‘:’, ‘CR’ and ‘LF.’ Ignore the
carry that may occur at the upper digit when adding up the data.
Example:
The method of calculating the LRC for the [:]110300C80004[LRC][CR][LF] command for
reading a series of four D registers of the device at station number 17, starting with the
D00201 (VT ratio) register, is as follows:
[1]Station number 17 is 11 in hexadecimal.
Change the data to byte-by-byte hex data ⇒ 11,03,00,C8,00,04.
(In the Modbus/ASCII message, this data is represented by the ASCII code as two
bytes, i.e., 31 and 31 in hexadecimal.)
[2]Add up the byte-by-byte hex data on a byte-by-byte basis.
⇒ 11 + 03 + 00 + C8 + 00 + 04 = E0
[3]Find the two's complement of the lower one byte of the data thus added up ⇒ 20
<Toc> <Ind><5. Modbus/RTU and ASCII Communication Protocols>
■ RTU Mode
In the RTU mode, errors are checked by means of a CRC-16 cyclic redundancy check.
The CRC-16 value is the 16-bit remainder when the value obtained by concatenating the 8
bits of all blocks (from the station number to the last data item) of a message, excluding the
start bit, stop bit and parity bit, is divided by a predetermined 17-bit binary number.
● Example of CRC-16 Calculation
When executing function code 03 (reads data from multiple D registers) to read the status
from the slave at station number 11 “0B”, send the 0B03002A0004 command.
[1]The initial value is FFFF. Find the XOR value of this initial value and the first character
(= station number 11).
[2]Refer to the lower byte of the result of executing the function code (or the upper byte, if
the result is regarded as a block of text). From the table, obtain the value corresponding to that byte. Since the result is “F4” in this example, you refer to the 244th value in
the table and obtain “8701”.
[3]Find the XOR value of the upper byte of the XOR operation in step [1] and the result of
step [2]. This value is the first character of the CRC-16 calculation.
[4]Using the result of step [3] (remainder) as the next initial value, make the same calcu-
lation to evaluate the second character (function code 03).
5-5
Initial valueFF FF
Station number 0B
--------XOR FF F4
Reference to table
XOR 87 FE
Function code 03
XOR 87 FD
Reference to table
XOR
•
•
•
XOR E5 9E
Last character 04
-------XOR E5 9A
Reference to table
Resulting error 6B 6
6B 80
--------
87 01
--------
--------
81 C1
------- 81 46
•
•
•
5
Convert the hex value to a decimal
value, find the corresponding number
in Table 5.2, and substitute the number
into the formula.
In the example shown on the left,
hex value “F4” is converted to decimal
value 244. From Table 5.2, the number
corresponding to 244 proves to be “8701”.
This number is substituted into the formula.
[5]Repeat steps [1] to [4] to perform the calculation up to the last character string 04.
[6]Reverse the order of the upper and lower bytes of 6B65 and append 656B to the end
of the character string as the error code.
0B03002A0004
First reverse the order of the upper and lower bytes of the calculated result, then compare the value with the received data or
store the value in the transmission buffer.
* Numbers in quotation marks are hexadecimal.
656B
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Table 5.2 Results of Performing CRC on 0th to 255th Values at “A001”
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5.1.4Configuration of Response
The PR300 receives a command message from the higher-level device. If the received
command message is found to be normal and directed at the station number of the PR300
itself, the PR300 concludes the content of the message to be normal. Thus, the PR300
enters the phase of executing message processing, deciphers the content of the command
message, and processes with the message.
The PR300 does not execute message processing, however, if the received command
message is found to be abnormal. In that case, the PR300 either ignores the received
message or creates a response message telling the received message is erroneous.
After receiving a normal command message and executing a given process, the PR300
creates and sends a response message to which error check data appropriate for the
command function code of the higher-level device is added.
■ Responses to Normal Messages
For a loop back function or a function for writing to a single register, the PR300 returns the
received command message as a response message.
For a function for writing to multiple D registers, the PR300 returns part of the received
command message as the response message.
For a readout function, the PR300 adds the read data to the ends of the station number
and function code of the received command message, and returns the message as the
response message.
5-7
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■ Responses to Abnormal Messages
If there is any failure other than transmission errors, the PR300 returns the following response message without executing any process:
5-8
1
2
Function
Code
(*1)
1
2
Error
Code
1
2
Error
Check
2
2
Element
Number of bytes in RTU mode
Number of bytes in ASCII mode
*1:The function code entered here is the function code (in hex) plus 80 (in hex).
Start of
Message
Mark (:)
None
1
Station
Number
(ST-NO)
The following table summarizes details on the error codes.
Error Code
01
02Abnormal D register number
03
Funcation code error
Abnormal number of D registers
Meaning
Cause
Function code does not exist.
D register number out of the range is specified.
Number of D registers out of the range is specified.
The PR300 does not regard it as an error even if there is any unused register among those
with consecutive register numbers specified by a readout function; rather, the PR300
returns a value of 0 in this case.
The PR300 returns the error code 02 or 03 if the specified consecutive registers are made
to fall outside the given range by the number of registers specified, even though the Dregister start number was initially within the range. (Depend on the function code.)
■ Cases when There Are No Responses to Transmitted Messages
[CR][LF]
None
2
•A transmission error (overrun, framing, parity, LRC or CRC-16 error) is encountered.
•The station number in the command message is wrong.
•The interval between data composing a message is longer than 2 seconds.
•The station number is “00” (broadcast specification).
•The receiving buffer has overflowed.
Note: As a measure against the abovementioned problems, add a time-out process to the communication function or
program of the higher-level device.
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5.1.5Specifying Broadcast
The corresponding multiple PR300s perform the function to receive and process a command in which this station number is specified.
(1)Specify “00” for the station number in the command to execute it.
(2)This command works independently of station numbers of slave stations.
(3)This command is applicable for writing only.
(4)No response is returned from the PR300 when communication is performed using this
command.
5-9
Higher-level device
RS-485 communication
Maximum communication distance: 1200 m
Maximum number of slave stations to be connected: 31
Figure 5.2 Broadcasting
Broadcast data.
* No response from slave stations
[Example]
Write 0001 into the D0400 (remote reset) using broadcast command.
[Message]
[:]0006018F000168[CR][LF]
“00”: broadcast addressing, “06”: function code 06,
“018F”: D register number 400, “0001”: data 0001, “68”: error check
* Numbers in quotation marks are hexadecimal.
No response is returned to the above message.
D-Reg No.
D040040400018FRemote reset
Ref No.H No.DescriptionEffective Range
If other than 1: Invalid
If 1: PR300 is reset
NOTE
•When remote reset is executed, maximum, minimum and instantaneous voltage
values and maximum and instantaneous current values will be reset. Optional integration is terminated if it is being performed.
•Even when remote reset is executed, active energy, reactive energy, and apparent
energy data as well as set parameter values are retained.
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5.2Message and Response
Function codes are command words used by the higher-level device to obtain the D
registers information of PR300.
Table 5.3 Function Codes
CodeFunction
03
Reads data from multiple D registers.
06
Writes data into D register.
08
Performs loop back test.
16
Writes data into multiple D registers.
Capable of reading data from a maximum of 64 successive
D registers between D0001 and D0400.
Capable of writing data into one D register between D0001
and D0400.
Used when checking communication wiring.
Capable of writing data into a maximum of 32 successive
registers between D0001 and D0400.
•The write function codes cannot be written into read-only or user-prohibited D registers.
•Broadcast addressing is possible with function codes 06 and 16 only. (Also in this
case, cannot be written into read-only or user-prohibited D registers.)
Description
5-10
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03Reads data from multiple D registers
● Function
This function code reads the contents of successive D registers by the specified number
starting with a specified D registers number.
•The maximum number of D registers to be read at a time is 64.
•For the format of responses in the event of failure, see subsection 5.1.4.
● Message (for normal operation)
5-11
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Message (continued)
Error
Check
End of Message Mark
2
2
Start of
Message
Mark (:)
None
1
(CR + LF)
None
2
Station
Number
(ST-NO)
1
2
● Response (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Response (continued)
Contents of
D Register
2
Start of
Message
Mark (:)
None
1
Error
Check
2
Station
Number
(ST-NO)
End of Message Mark
Function
Code
(03)
1
2
(CR + LF)
None
Function Code
1
2
(03)
Byte
Count
1
2
1
2
D-Register
Start Number
Contents of
D Register
2
4
Number of
D Registers
2
44
...
...
...
2
4
2
2
● Example (ASCII mode)
Read a series of four D registers starting with the D0201 (VT ratio and CT ratio) at station
number 11.
[Message][:]0B0300C8000426[CR][LF]
“0B”:station number 11, “03”: function code 03, “00C8”: D register start number 201, “0004”:
number of D registers 4, and “26”: error check
* Numbers in quotation marks are hexadecimal.
The following response will be returned to the message above.
[Response][:]0B030800003F8000003F806C[CR][LF]
* The VT ratio and CT ratio data are floating point values. The combined value of D0201 and
D0202, 00003F80, represents 1. That of D0203 and D0204, which is also 00003F80,
represents 1 as well (the upper four digits, 3F80, and the lower four digits, 0000, are reversed).
* The floating point value of 3F800000 is the decimal equivalent of 1.
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06Writes data into D register
● Function
This function code writes data into a specified D registers number.
•The maximum number of D registers to be written into at a time is 1.
•For the format of response in the event of failure, see subsection 5.1.4.
•Broadcast addressing is possible (by setting “00” to the station number).
● Message (for normal operation)
5-12
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Message (continued)
Write Data
(Upper Digit)
1
2
(Lower Digit)
Start of
Message
Mark (:)
None
Write Data
1
2
Station
Number
(ST-NO)
1
1
Error
Check
2
End of Message Mark
2
2
● Response (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Response (continued)
Write Data
(Upper Digit)
1
(Lower Digit)
Start of
Message
Mark (:)
None
Write Data
1
Station
Number
(ST-NO)
1
1
Error
Check
2
End of Message Mark
2
Function Code
(CR + LF)
None
2
Function Code
(CR + LF)
None
(06)
1
2
(06)
1
2
D-Register
Number
(Upper Digit)
1
22
D-Register
Number
(Upper Digit)
1
22
D-Register
Number
(Lower Digit)
1
D-Register
Number
(Lower Digit)
1
2
2
2
2
● Example (ASCII mode)
Write 0001 into the D0302 (optional integration start/stop) at station number 11.
[Message][:]0B06012D0001C0[CR][LF]
“0B”: station number 11, “06”: function code 06, “012D”: D register number 302, “0001”:
data 0001, and “C0”: error check
* Numbers in quotation marks are hexadecimal.
The following response will be returned to the message above.
[Response][:]0B06012D0001C0[CR][LF]
The frame same as the message is returned.
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08Performs loop back test
● Function
This function code is used to check connection for communication.
•For the format of response in the event of failure, see subsection 5.1.4.
•The “00” shown below (marked with an asterisk *) are fixed.
•Any value can be selected for transmit data.
● Message (for normal operation)
5-13
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Message (continued)
Error
Check
End of Message Mark
2
2
Start of
Message
Mark (:)
None
1
(CR + LF)
None
2
Station
Number
(ST-NO)
1
2
● Response (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Response (continued)
Error
Check
End of Message Mark
2
Start of
Message
Mark (:)
None
1
(CR + LF)
None
Station
Number
(ST-NO)
1
2
Function Code
(08)
1
2
Function Code
(08)
1
2
00
0000
2
44
00
0000
2
44
Transmit Data
(Arbitrary)
2
Same as
Transmit Data
2
2
2
● Diagnostic Codes
Diagnostic Code
0000
Command message return
Meaning
Data
Arbitrary
● Example (ASCII mode)
Send data 0000 (fixed) and transmit data 04D2 (arbitrary) to the station number 11 to check
the connection for communication.
[Message][:]0B08000004D217[CR][LF]
When the connection is normal, the following response same as the command will be
returned.
[Response][:]0B08000004D217[CR][LF]
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16Writes data into multiple D registers
● Function
This function code writes data into successive D registers by the number starting with a
specified D registers number.
•The maximum number of D registers to be written into at a time is 32.
•For the format of response in the event of failure, see subsection 5.1.4.
•Broadcast addressing is possible (by setting “00” to the station number).
No response is returned when using the broadcast addressing.
● Message (for normal operation)
5-14
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Massage (continued)
Number of
D Registers
(Upper Digit)
1
22
Start of
Message
Mark (:)
None
1
Number of
D Registers
(Lower Digit)
1
Byte
Count
1
2
Station
Number
(ST-NO)
1
2
(Upper Digit)
● Response (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Response (continued)
Number of
D Registers
(Upper Digit)
1
Start of
Message
Mark (:)
None
1
Number of
D Registers
(Lower Digit)
1
Station
Number
(ST-NO)
1
2
Error
Check
2
Function
Code
(10)
End of Message
Function Code
Data
1
2
Start Number
(Upper Digit)
1
2
Mark
(CR + LF)
None
(10)
1
2
Data
(Lower Digit)
1
2
D-Register
1
22
D-Register Start
Number
(Upper Digit)
1
22
…
…
…
D-Register
Start Number
(Lower Digit)
1
D-Register Start
Error
Check
2
2
Number
(Lower Digit)
1
End of Message
Mark
(CR + LF)
None
2
2
2
2
2
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● Example (ASCII mode)
Write 10 into a series of four D registers starting with the D0201 (VT ratio and CT ratio) at
station number 11.
[Message][:]0B1000C800004120000041204F[CR][LF]
“0B”: station number 11, “10”: function code 16, “00C8”: D register start number 201,
“0004”: number of D registers 4, “08”: byte count (number of D registers × 2), “0000”: VTratio lower two bytes, “4120”: VT ratio upper two bytes, “0000”: CT ratio lower two bytes,
“4120”: CT ratio upper two bytes and “4F”: error check
* Numbers in quotation marks are hexadecimal.
The following response will be returned to the message above.
[Response]
[:]0B1000C8000419[CR][LF]
Write 1 into the D0207(setup change status) to activate the writing into the VT ratio and CT
ratio.
[:]0B0600CE000120[CR][LF]
“0B”: station number 11, “06”: function code 06, “00CE”: D register start number 207,
“0001”: writing data 0001, and “20”: error check
5-15
* Numbers in quotation marks are hexadecimal.
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6.Modbus/TCP Communication Protocol
6.1Overview
Modbus/TCP is one of the protocol used to communicate with devices such as PCs
or PLCs (sequencers) using the TCP/IP protocol via Ethernet and other networks.
This communication protocol is used to perform read/write operations with the D
registers in the PR300 and exchange data with connected devices.
The PR300 can be connected to IEEE802.3-compliant networks (10BASE-T/
100BASE-TX). Generally, the Modbus/TCP protocol communicates through port 502.
In addition, the PR300 operates as Ethernet-serial gateway. A higher-level device can
exchange data with other serial communication devices using the Modbus/TCP
protocol via the PR300.
Higher-level devices (PC etc.)
6-1
Application Layer
Transport Layer
Network Layer
Data link Layer
Physical Layer
Figure 6.1 Network Layer
Modbus/TCP
TCP
IP
ETHERNET
10BASE-T/100BASE-TX
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(Example)
Higher-level device
IP address [192.168.1.1]
(arbitrary)
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
PR300 as
Ethernet-serial
gateway function
HUB
LAN
connection
6-2
Station number 01 (fixed)
IP address [192.168.1.2]
(arbitrary)
RS-485 connection
Station number 02
(arbitrary)
Station number 01 (fixed)
IP address [192.168.1.3]
(arbitrary)
Station number 03
(arbitrary)
Station number 01 (fixed)
IP address [192.168.1.4]
(arbitrary)
Figure 6.2 Example of Connection for Modbus/TCP Communication
See Also
Chapter 7 for information on the D registers.
Station number 01 (fixed)
IP address [192.168.1.5]
(arbitrary)
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6.2TCP/IP Communication
Modbus/TCP communicates with other devices, following the procedure below,
through the TCP/IP socket interface.
PC
Ethernet
PR300 with Ethernet
communication function
6-3
Initial Setup
socket()
connect()
send()
recv()
close()
Figure 6.3 TCP/IP Communication
Open connection
Command
Response
Terminate
connection
Initial Setup
socket()
bind()
listen()
accept()
recv()
send()
close()
NOTE
If no request is received from the higher-level device for more than 60 seconds after establishing a connection, the PR300 will automatically terminate the connection.
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6.3Network Frame Structure
The Modbus/TCP frame structure is as follows:
MODBUS TCP/IP ADU
MBAP HeaderFunction codeData
PDU
MBAP Header (Modbus Application Protocol Header) : Header used to identify the Modbus/TCP protocol
PDU: simple Protocol Data Unit
6.3.1MBAP Header Structure
The MBAP Header (Modbus Application Protocol Header) consists of the following seven
bytes.
Byte No01234 5 6
6-4
Description
Transaction ID: Set any value for identifying the transaction. The PR300 returns a value received from a higher-level device
Protocol ID: Specify “0” for the Modbus/TCP protocol.
Number of bytes: Number of bytes after the unit ID (byte number 6)
Unit ID: For the communication with the PR300 itself, specify “01” for the higher-level device. The PR300 returns “01” as a
Transaction ID
as a response.
response. For the communication with the device connected to the RS-485 communication terminals of the PR300
using the Ethernet-serial gateway function, specify its station number (02 to 99). The device returns the same value as
a response.
6.3.2PDU Structure
The PDU (simple Protocol Data Unit) consists of the following n bytes.
Byte No01 to (n-1)
Description
Function code: Specify a command (function code) from a higher-level device.
Data: Specify D register numbers, number of D registers, parameter values, or others in accordance with the function code.
(expressed in hexadecimal in the request)
Function code
Protocol IDUnit IDNumber of bytes
Data
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6.4Communication with Higher-level Devices
6.4.1List of Function Codes
The codes in the following list are command words higher-level devices use to acquire
information from the internal registers (D registers) of the PR300.
6-5
CodeFunction
03
Reads data from multiple D registers.
06
Writes data into D register.
08
Performs loop back test.
16
Writes data into multiple D registers.
The write function codes cannot be written into read-only or use-prohibited D registers.
6.4.2Specifying D Registers
Follow the procedures below to specify a D register from a higher-level device:
(1)If using commercially available SCADA or other software, specify the Ref No. indicated
in Chapter 7, “Functions and Usage of D Registers.”
(2)For customer-created communication programs, specify the H No. indicated in Chap-
ter 7, “Functions and Usage of D Registers.”
Example: To specify D0301 as the integration start/stop,
*Specify Ref. No. 40301 for a request using commercially available SCADA or other
software.
Description
Capable of reading data from a maximum of 64 successive
D registers between D0001 and D0400.
Capable of writing data to one D register between D0001 and
D0400.
Used when checking communication wiring.
Capable of writing data into a maximum of 32 successive
register between D0001 and D0400.
*Specify H No. “012C” for a request using customer-created communication program.
IM 77C01E01-10E
<Toc> <Ind>< 6. Modbus/TCP Communication Protocol>
6.4.3Request and Response
03Reads data from multiple D registers
● Function
This function code reads the contents of successive D registers by the specified number
starting with a specified D registers number.
•The maximum number of D registers to be read at a time is 64.
•For the format of responses in the event of failure, see subsection 6.4.4.
● Request (for nomal operation): Reading data from n registers
6-6
Element
Number of bytes
Command
element
Hex value
MBAP Header
22 22211
Transaction ID
Arbitrary00000006n
Protocol ID
Number of
bytes
Unit ID
01 to 99
Function
code
03
start number
Register
PDU
Number of
registers
● Response (for normal operation)
Element
Number of bytes
Command
element
Hex value
22 222111
Transaction ID
Arbitrary00002n+3032n
MBAP Header
Protocol ID
Number of
bytes
Unit ID
01 to 99
Function
code
Byte
count
Contents of
register 1
PDU
● ● ● ●
● Example
Read a series of four D registers starting with D0201 (VT ratio and CT ratio) at station
number 01.
[Request] 000100000006010300C80004
(1)(2)(3) (4) (5) (6)(7)
Contents of
register n
(1) “0001”: Arbitrary 2-byte data (2) “0000”: Protocol ID=0000 (fixed)
(3) “0006”: Number of bytes (4) “01”: Unit ID = 01 indicating PR300
(5) “03”: Function code 03 (6) “00C8”: D register start number 201
(7) “0004”: Number of D registers = 4
The following response will be returned to the request above:
[Response] 00010000000B01030800003F8000003F80
* The VT ratio and CT ratio data are floating point values. The combined value of D0201 and
D0202, 00003F80, represents 1. That of D0203 and D0204, which is also 00003F80,
represents 1 as well (the upper four digits, 3F80, and the lower four digits, 0000, are reversed).
* The floating point value of 3F800000 is the decimal equivalent of 1.
(1)(2)(3) (4) (5) (6)
D0201 and
D0202
D0203 and
D0204
(1) “0001”: The arbitrary 2-byte data in the request
(2) “0000”: Protocol ID = 0000 (fixed) (3) “000B”: Number of bytes
(4) “01”: Unit ID = 01 indicating PR300 (5) “03”: Function code 03
(6) “08”: Byte count
* Numbers in quotation marks are hexadecimal.
IM 77C01E01-10E
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