Mitsubishi MELSEC QJ71C24N User manual

Serial Communication
Module
User's Manual
(Hardware)
QJ71C24N, QJ71C24N-R2
QJ71C24N-R4
QJ71C24, QJ71C24-R2
Thank you for purchasing the Mitsubishi programmable controller
MELSEC-Q Series.
Prior to use, please read this and relevant manuals thoroughly to
fully understand the product.
MODEL QJ71C24-U-HW-JE
MODEL
CODE 13JQ31
IB(NA)-0800008-I (0807)MEE
©1999 MITSUBISHI ELECTRIC CORPORATION

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DANGER
CAUTION
•SAFETY PRECAUTIONS •
(Be sure to read these instructions before using the product.)
Before using this product, please read this manual and the relevant manuals
introduced in this manual carefully and pay full attention to safety to handle the
product correctly.
Note that these precautions apply only to this product. Refer to the user's
manual of the CPU module for the programmable controller system safety
precautions.
In this manual, the safety instructions are ranked as "DANGER" and
"CAUTION".
Indicates that incorrect handling may cause hazardous
conditions, resulting in death or severe injury.
Indicates that incorrect handling may cause hazardous
conditions, resulting in medium or slight personal injury or
physical damage.
Note that the CAUTION level may lead to a serious consequence
according to the circumstances.
Always follow the instructions of both levels because they are important to
personal safety.
Please save this manual to make it accessible when required and always
forward it to the end user.

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[Design Instructions]
CAUTION
zDo not bunch the control wires or communication cables with the main
circuit or power wires, or install them close to each other.
They should be installed 100mm(3.9inch) or more from each other.
Not doing so could result in noise that may cause malfunction.
[Installation Instructions]
CAUTION
zUse the programmable controller in an environment that meets the general
specifications contained in the user's manual of the CPU module to use.
Using this programmable controller in an environment outside the range of
the general specifications could result in electric shock, fire, erroneous
operation, and damage to or deterioration of the product.
zWhile pressing the installation lever located at the bottom of module, insert
the module fixing tab into the fixing hole in the base unit until it stops. Then,
securely mount the module with the fixing hole as a supporting point.
Incorrect loading of the module can cause a malfunction, failure or drop.
When using the programmable controller in the environment of much
vibration, tighten the module with a screw.
zTighten the screw in the specified torque range.
Undertightening can cause a drop, short circuit or malfunction.
Overtightening can cause a drop, short circuit or malfunction due to
damage to the screw or module.
zCompletely turn off the externally supplied power used in the system before
mounting or removing the module.
Not doing so could result in damage to the product.
zDo not directly touch the conductive area or electronic components of the
module.
Doing so may cause malfunction or failure in the module.

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[Wiring Instructions]
CAUTION
zWhen turning on the power and operating the module after installation and
wiring are completed, always attach the terminal cover that comes with the
product.
There is a risk of electric shock if the terminal cover is not attached.
zPerform correct pressure-displacement, crimp-contact or soldering for
external wire connections using the tools specified by the manufactures.
Incorrect connection may cause short circuits, fire, or malfunction.
zAttach connectors to the module securely.
zBe sure to fix communication cables or power supply cables leading from
the module by placing them in the duct or clamping them.
Cables not placed in the duct or without clamping may hang or shift,
allowing them to be accidentally pulled, which may cause a module
malfunction and cable damage.
zBefore connecting the cables, check the type of interface to be connected.
Connecting or erroneous wiring to the wrong interface may cause failure to
the module and external devices.
zTighten the terminal screws within the range of specified torque.
If the terminal screws are loose, it may result in short circuits or
malfunction.
If the screws are tightened too much, it may cause damage to the screw
and/or the module, resulting in fallout, short circuits or malfunction.
zWhen removing the communication cable or power supply cable from the
module, do not pull the cable. When removing the cable with a connector,
hold the connector on the side that is connected to the module.
When removing the cable connected to the terminal block, first loosen the
screws on the part that is connected to the terminal block.
Pulling the cable that is still connected to the module may cause
malfunction or damage to the module or cable.
zBe sure there are no foreign substances such as sawdust or wiring debris
inside the module. Such debris could cause fires, damage, or erroneous
operation.
zThe module has an ingress prevention label on its top to prevent foreign
matter, such as wire offcuts, from entering the module during wiring.
Do not peel this label during wiring.
Before starting system operation, be sure to peel this label because of heat
dissipation.

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Revisions
The manual number is given on the bottom right of the cover.
Print Date Manual Number Revision
Sep., 1999 IB(NA)-0800008-A First printing
Dec., 1999 IB(NA)-0800008-B Addition
"Compliance with the EMC Directive and Low Voltage
Directive", Chapter 6 (1) (a) · (c) ·(2) REMARK
Correction
"Safety Precautions", Chapter 2, Section 5.2 (3)
Sep., 2000 IB(NA)-0800008-C Add the contents of the function version B.
Put Windows®base software products together from
Mitsubishi Programmable Controller MELSEC series to
Mitsubishi integrated FA software MELSOFT series.
Standardize the name from software package (GPP
function) to product name (GX Developer).
Correction
"Safety Precautions", "Manuals", "Compliance with the
EMC Directive and Low Voltage Directive", Chapter 2,
Chapter 6(1)(b)(c).
Dec., 2002 IB(NA)-0800008-D Addition model
QJ71C24N, QJ71C24N-R2, QJ71C24N-R4
Feb., 2003 IB(NA)-0800008-E Addition
Chapter 1, Section 3.1
Mar., 2006 IB(NA)-0800008-F Correction
"Safety Precautions", "Compliance with the EMC and
Low Voltage Directives", Section3.1, 5.2, Chapter 7
Sep., 2007 IB(NA)-0800008-G
Change of a term
"PLC" was changed to "programmable controller".
Correction
Section 3.1, Chapter 4, Section 5.1, 5.2, Chapter 7
Jan., 2008 IB(NA)-0800008-H
Correction
Section 3.1, Chapter 4, 7
Jul., 2008 IB(NA)-0800008-I Correction
"Compliance with the EMC and Low Voltage Directives",
Section 3.1, 5.2
This manual confers no industrial property rights or any rights of any other kind, nor does
it confer any patent licenses. Mitsubishi Electric Corporation cannot be held responsible
for any problems involving industrial property rights which may occur as a result of using
the contents noted in this manual.
©1999 MITSUBISHI ELECTRIC CORPORATION

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CONTENTS
1. Overview······································································································ 1
2. Performance Specifications ········································································· 2
3. Mounting and Installation ············································································· 3
3.1 Handling Precautions ············································································· 3
3.2 Installation Environment ········································································· 3
4. Part Names·································································································· 4
5. External Wiring ···························································································· 6
5.1 Connecting to the RS-232 line································································ 6
5.2 Connecting to the RS-422/485 line························································· 9
6. Settings for GX Developer ········································································· 13
7. External Dimensions ·················································································· 16
About Manuals
The following table lists manuals relating to this product.
If necessary, obtain a proper manual in accordance with the intended use.
Relevant Manuals
Manual name Manual No.
(Model code)
Q Corresponding Serial Communication Module
User's Manual (Basic)
SH-080006
(13JL86)
Q Corresponding Serial Communication Module
User's Manual (Application)
SH-080007
(13JL87)
Q Corresponding MELSEC Communication Protocol
Reference Manual
SH-080008
(13JF89)
Please read the Q Corresponding Serial Communication Module User's
Manual (Basic) before using this module.

1
Compliance with the EMC and Low Voltage Directives
(1) For programmable controller system
To configure a system meeting the requirements of the EMC and Low
Voltage
Directives when incorporating the Mitsubishi programmable controller
(EMC and Low Voltage Directives compliant) into other machinery or
equipment, refer to Chapter 9 "EMC AND LOW VOLTAGE DIRECTIVES"
of the QCPU User's Manual (Hardware Design, Maintenance and
Inspection).
The CE mark, indicating compliance with the EMC and Low Voltage
Directives, is printed on the rating plate of the programmable controller.
(2) For the product
No additional measures are necessary for the compliance of this product
with the EMC and Low Voltage Directives.
1. Overview
This manual is written to provide proper information and instructions on
installation and wiring of the QJ71C24N, QJ71C24N-R2, QJ71C24N-R4,
QJ71C24 and QJ71C24-R2 serial communication modules (hereinafter referred
to as the serial communication module).
Check that the following items are included with the product package.
Model name Product name Quantity
QJ71C24N or QJ71C24 serial communication module 1
Terminal resistor for RS-422 communication 330 1/4 W
(Orange-Orange-Brown) *1 2
QJ71C24N or
QJ71C24 Terminal resistor for RS-485 communication 110 1/2 W
(Brown-Brown-Brown) *1 2
QJ71C24N-R2
or QJ71C24-R2
QJ71C24N-R2 or QJ71C24-R2 serial communication
module 1
QJ71C24N-R4 serial communication module 1
RS-422/485 plug-in connector socket block 2
Terminal resistor for RS-422 communication 330 1/4 W
(Orange-Orange-Brown) *1 4
Terminal resistor for RS-485 communication 110 1/2 W
(Brown-Brown-Brown) *1 4
QJ71C24N-R4
Plate terminal for braided shield cable connection 4
1: Differentiate the terminal resistors as follows:
330 110
Brown
Orange Orange Brown Brown Brown

2
2. Performance Specifications
The following describes the performance specifications of the serial
communication module.
Use the modem function with reference to the relevant performance
specifications in the user's manual (Basic).
For general specifications of the serial communication module, refer to the
user's manual of the CPU module.
Specifications (when the modern function is not used)
Item QJ71C24N
QJ71C24
QJ71C24N-R2
QJ71C24-R2 QJ71C24N-R4
CH1 RS-232-compliance
(D-sub 9pin)
RS-232-compliance
(D-sub 9pin)
RS-422/485-compliance
(2-piece plug-in
connector socket block)
Interface
CH2 RS-422/485-compliance
(2-piece terminal block)
RS-232-compliance
(D-sub 9pin)
RS-422/485-compliance
(2-piece plug-in
connector socket block)
Synchronization method Start-stop synchronization method
[QJ71C24N(-R2/R4)]
50 300 600 1200 2400 4800 9600
14400 19200 28800 38400 57600 115200 230400 (bps)
•Transmission speed 230400 bps is available for only CH1. (Not
available for CH2)
•Total transmission speed of two interfaces is available up to 230400
bps.
•Total transmission speed of two interfaces is available up to 115200
bps when the communication data monitoring function is used.
[QJ71C24(-R2)]
50 300 600 1200 2400 4800 9600
14400 19200 28800 38400 57600 115200 - (bps)
Transmission speed
•Total transmission speed of two interfaces is available up to 115200
bps.
Start bit 1
Data bit 7/8
Parity bit 1(vertical parity) or none
Data format
Stop bit 1/2
Parity check For all protocol, select odd/even by the parameter when there is an error.
Error detection Sum check
code
Select by the parameter for MC protocol/Bidirectional protocol.
Select by the user entry frame for non-procedure protocol.
RS-232 Maximum 15 m
(49.2 ft.)
Maximum 15 m
(49.2 ft.) -
Transmission
distance
(Overall
distance) RS-422/485
Maximum 1200 m
(4592.4 ft.)
(overall distance)
-
Maximum 1200 m
(4592.4 ft.)
(overall distance)
Allowable number of writes
to flash ROM Maximum 100,000 writes to the same area
Number of occupied I/O
points 32 points per slot (I/O assignment: Intelli: 32 points)

3
Specifications (when the modern function is not used)
Item QJ71C24N
QJ71C24
QJ71C24N-R2
QJ71C24-R2 QJ71C24N-R4
RS-232 7/0. 127 P HRV-SV Outside diameter 8.5mm (0.33in.) or more
(Oki Electric Cable Co., Ltd. Applicable number is specified in .)
Recommended
cable RS-422/485
(*1)
SPEV (SB)-MPC-0.2 3P Outside diameter approx. 6.5mm (0.26 in.)
(Mitsubishi Cable Industries, LTD.)
SPEV(SB)-0.2 3P Outside diameter approx. 7.5mm (0.3 in.)
(Mitsubishi Cable Industries, LTD.)
Applicable connector for
external wiring D-sub 9 pin (male) screw type (*2) -
5V DC internal current
consumption 0.31A 0.26A 0.39A
External dimensions 98 (3.86 in.) (H) 27.4 (1.08 in.) (W) 90 (3.54 in.) (D)[mm]
Weight 0.20kg (0.44lb)
1: Recommended cables SPEV (SB)-MPC-0.2 3P and SPEV (SB)-0.2 3P
are equivalent in the electrical characteristics, but partially different in the
outside diameter, internal wire colors, etc.
2: Refer to Section 5.1 for the recommended cable.
3. Mounting and Installation
3.1 Handling Precautions
(1) Do not drop the module or subject it to heavy impact since it is made of
resin.
(2) Always make sure to touch the grounded metal to discharge the electricity
charged in the body, etc., before touching the module.
Failure to do so may cause a failure or malfunctions of the module.
(3) Tighten the screws such as module fixing screws within the following
ranges.
Screw location Tightening torque range Remarks
RS-422/485 terminal block
terminal screw (M3 screw) 0.42 to 0.58N•m -
RS-422/485 plug-in connector
socket terminal screw for
QJ71C24N-R4 (M2 screw)
0.20 to 0.25N•m -
RS-232 cable connector
screw (M2.6 screw) 0.20 to 0.39N•m
Screw hole depth:
L=3.2mm or less
(Internal length from the
surface)
Module fixing screw (normally
not required) (M3 screw) ( 1) 0.36 to 0.48N•m -
1: The module can be easily fixed onto the base unit using the hook at the
top of the module.
However, it is recommended to secure the module with the module
fixing screw if the module is subject to significant vibration.
3.2 Installation Environment
For further details, refer to the user's manual for the CPU module.

4
4. Part Names
QJ71C24N
QJ71C24 ( 1)
QJ71C24N-R2
QJ71C24-R2 ( 2)
QJ71C24N-R4
1)
3)
2)
1)
4)
4)
1)
2)
2)
5) 5) 5)
*1: The appearance of the QJ71C24 is almost the same as that of the
QJ71C24N, except for the model name part and serial number plate.
*2: The appearance of the QJ71C24-R2 is almost the same as that of the
QJ71C24N-R2, except for the model name part and serial number plate.
Name Contents
1) Display LED Display LED (For details, see Section (1).)
2) RS-232 Interface RS232 interface for serial communication with external devices
(D-Sub 9pin)
3) RS-422/485
Interface
RS422/485 interface for serial communication with external
devices (2-piece terminal block)
4) RS-422/485
Interface
RS422/485 interface for serial communication with external
devices (2-piece plug-in socket block)
5) Serial number
plate Indicates the serial No. of the serial communication module.

5
(1) LED display list
ERR.
CH2
CH1 SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N
ERR.
CH2
CH1 SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N-R2
ERR.
CH2
CH1 SD
RD
NEU.
SD
NEU.
RD
RUN
QJ71C24N-R4
Compatible protocol
CH LED Display
contents On/flashing Off MC Non-
procedural Bidirectional
RUN
Normal
operation
display
Normal Faulty or reset
-
ERR. Error display
(*1)
Error has
occurred Normal
Valid
NEU.
(*3)
Neutral status
on the CH1 side
display (*2)
Waiting for MC
command
message to be
received
MC command
message being
received
Valid Invalid (Off)
SD Transmission
status display
Data being
transmitted
Data not
transmitted
CH1
RD Reception
status display
Data being
received
Data not
received
Valid
NEU.
(*3)
Neutral status
on the CH2 side
display (*2)
Waiting for MC
command
message to be
received
MC command
message being
received
Valid Invalid (Off)
SD Transmission
status display
Data being
transmitted
MC command
message not
transmitted
CH2
RD Reception
status display
Data being
received
MC command
message not
received
Valid
1: This LED comes on when an error occurs at Q series C24 hardware
or during data communication.
2: This LED displays the data communication status via MC protocol.
On: Waiting for the command message to be received from the
external device.
Off: Processing the command message received from the external
device.
3: This LED can be made valid also when "GX Developer connection"
(0H) is specified in communication protocol setting.

6
5. External Wiring
5.1 Connecting to the RS-232 line
This section explains the standard method for connecting the RS-232 line.
Data terminal ready
Signal ground
CD
RD(RXD)
SD(TXD)
DTR(ER)
SG
DSR(DR)
RS(RTS)
CS(CTS)
RI(CI)
Pin
number
Signal
abbreviation
Signal direction
External
device
1
2
3
4
5
6
7
8
9
C24
( 1)
9
1
2
3
4
5
6
7
8
Signal name
Carrier detect
Receive data
Send data
Dataset ready
Request to send
Clear to send
Call Indicate
1: QJ71C24N, QJ71C24 : CH1 side,
QJ71C24N-R2 QJ71C24-R2 : CH1/CH2 side
The following RS-232 interface connector is used for the module.
•DDK Ltd.
9-pin D-sub (female) screw type
17L-10090-27 (D9AC)(-FA)
Use one of the following as a connector shell for the connection cable of the
module side.
•DDK Ltd.
Plug, shell: 17JE-23090-02 (D8A)(-CG)
POINT
To connect the module with a modem/TA when using modem function, install wiring as
specified for the modem/TA.

7
(1) Connection example with an external device capable of turning on and off
the CD signal (pin No. 1)
The module External device
Signal
name Pin number
Cable connection and signal direction
(Connection example of full or half
duplex communication) Signal name
CD 1 CD
RD(RXD) 2 RD(RXD)
SD(TXD) 3 SD(TXD)
DTR(ER) 4 DTR(ER)
SG 5 SG
DSR(DR) 6 DSR(DR)
RS(RTS) 7 RS(RTS)
CS(CTS) 8 CS(CTS)
RI(CI) 9
(2) Connection example with an external device not capable of turning on and
off the CD signal (pin No. 1)
(a) Example of connection for DC code control or DTR/DSR control
The module External device
Signal
name Pin number
Cable connection and signal direction
(Connection example of full duplex
communication) Signal name
CD 1 CD
RD(RXD) 2 RD(RXD)
SD(TXD) 3 SD(TXD)
DTR(ER) 4 DTR(ER)
SG 5 SG
DSR(DR) 6 DSR(DR)
RS(RTS) 7 RS(RTS)
CS(CTS) 8 CS(CTS)
RI(CI) 9
(b) Example of connection for DC code control
The module External device
Signal
name Pin number
Cable connection and signal direction
(Connection example of full duplex
communication) Signal name
CD 1 CD
RD(RXD) 2 RD(RXD)
SD(TXD) 3 SD(TXD)
DTR(ER) 4 DTR(ER)
SG 5 SG
DSR(DR) 6 DSR(DR)
RS(RTS) 7 RS(RTS)
CS(CTS) 8 CS(CTS)
RI(CI) 9

8
(3) Connection precaution
(a) Connect the FG signal and shield of the connection cable as indicated
below:
Connection method Remark
FG signal Connect to the connector
enclosure of the module.
Shield
Connect to the FG terminal of
the external device or
connector enclosure of the
module.
• Do not short the FG signal and SG signal
of the connector cable.
• When the FG signal and SG signal are
internally connected in the external device,
do not connect the FG signal to the
module.
(b) When normal data communication is not obtained due to external
noise, perform the wiring as follows:
•Connect the FG terminal on the external device and the connector
enclosure of the module using the shield of the connection cable.
•Signals other than SG should be connected with SG signals in the
twisted pair.
FG
RD
SD
DTR
DSR
SG
RD
SD
DTR
DSR
SG
Connector
enclosure
Module Shield (External device)

9
5.2 Connecting to the RS-422/485 line
This section explains the standard method for connecting the RS-422/485 line.
Signal
abbreviation Signal name
Signal direction
External
device
C24
Signal ground
Frame ground
SDB
RDA
RDB
SG
FG
Frame ground
FG
( 1)
SG
SDA
SDB
RDA
RDB
SG
RDB
RDA
SDB
SDA
QJ71C24N-R4 ( 2) QJ71C24N
QJ71C24
(FG)
(FG)
(FG) SDA Send data (+)
Send data (-)
Receive data (+)
Receive data (-)
1 QJ71C24N, QJ71C24 : CH2 side, QJ71C24N-R4 : CH1/CH2 side
2 Connect the RS-422/485 line of QJ71C24N-R4 while paying full attention
to the followings:
1) Use the RS-422/485 cable recommended in chapter 2. Performance
specifications. Be sure to strip the outer insulation layer by 7mm before
connecting the cable to the plug-in socket block.
2) When connecting the braided shield wire inside the RS-422/485 cable,
use the plate terminals included with the product. The braided shield
wire can be connected without the plate terminal. Four plate terminals
are included to connect the FG terminals of the both stations. (Refer to
section 5.2 (6))
3) When connecting the plug-in socket block to the QJ71C24N-R4, be
sure to confirm the layout of the socket block and then insert it into the
RS-422/485 connector on the QJ71C24N-R4.
SG
RDB
RDA
SDB
SDA
(FG)
Plate terminal
(included with product)
Braided shield wire
7mm
(0.28in.)
CH2
CH1
RS-422/485
RS-422/485
QJ71C24N-R4
SG
RDB
RDA
SDB
SG
RDB
RDA
SDB
SDA
SDA
QJ71C24N-R4
RUN
RD
NEU.
SD
NEU.
RD
SD
CH1 CH2
ERR.
(FG)
(FG)
4) Connect the external device according to its specifications.
5) See Appendix 5 for the bend radius of the connection cable.

10
POINT
If the module is the first or last station on the RS-422/485 line, connect the following
terminal resistor to the RS-422/485 interface with reference to the examples shown below.
Data communication will be disturbed if a terminal resistor is not used.
•For RS-422 communication .............................. 330 Ω1/4 W
•For RS-485 communication .............................. 110 Ω1/2 W
The Rin the examples shown below indicates a terminal resistor.
(1) Example of one-to-one connection between an external device and the
module (RS-422, RS-485)
Terminal
resistor
R
R
Module
Signal name
SDA
SDB
RDA
RDB
External device
RDA
RDB
SDA
SDB
RSA
RSB
CSA
CSB
SG
FG
SG
FG
FG
Signal name Terminal
resistor
(2) Example of one-to-n connection between an external device and the
module (RS-485 between C24s)
(a) Connecting an external device and the module using RS-232
Terminal resistor
R
R
R
R
R
Link operation
SDA
SDB
RDA
RDB
SG
FG
SDA
SDB
RDA
RDB
SG
FG
SDA
SDB
RDA
RDB
SG
FG
SD
RD
SD
RD
External device C24 1) C24 2) C24n
RS-422/485
cable
RS-422/485
cable
RS-232
(b) Connecting an external device and the module using RS-485
Terminal resistor
R
R
R
SDA
SDB
RDA
RDB
SG
FG
SDA
SDB
RDA
RDB
SG
FG
External device C24 1) C24 2) C24n
RS-422/485
cable
RS-422/485
cable
SDA
SDB
RDA
RDB
SG
FG
R
R
SDA
SDB
RDA
RDB
SG
FG
RS-422/485
cable

11
(3) Example of one-to-n connection between external devices and the module
(RS-485)
Terminal registor
R
SDA
SDB
RDA
RDB
SG
FG
RS-422/485
cable
RS-422/485
cable
SDA
SDB
RDA
RDB
SG
FG
R
SDA
SDB
RDA
RDB
SG
FG
SDA
SDB
RDA
RDB
SG
FG
RS-422/485
cable
R
External device 1) C24 1) External device 2) External device n
(4) Example of m-to-n connection between external devices and the modules
(RS-485)
Terminal resistor
R
SDA
SDB
RDA
RDB
SG
FG
External device 1) External device 2)
C24 1) C24n
SDA
SDB
RDA
RDB
SG
FG
R
SDA
SDB
RDA
RDB
SG
FG
SDA
SDB
RDA
RDB
SG
FG
RS-422/485
cable
R
RS-422/485
cable
RS-422/485
cable
(5) Error receive data countermeasures at external device during RS-422/485
connection
If the external device may receive erroneous data, install a pull-up or pull-
down resistor to the external device as follows.
Installing a pull-up or pull-down resistor (resistance value criteria: approx.
4.7 k 1/4 W) can prevent the reception of erroneous data.
Receive data
4.7 k 1/4 W
4.7 k 1/4 W
Terminal resistor
RDA
RDB
+
-
External device
POINT
When there is a pull-up or pull-down resistor at the external device, erroneous data is
not received.

12
(6) Connection precautions
(a)When connecting the SG and FG signals of the module to the external
device, connect them according to the specifications of the external
device.
(b) Connect the shield of the connection cable to the FG terminal on either
of the connected devices.
(c) If normal data communication is not obtained due to external noise
even if wiring is made as shown above, perform wiring as follows:
•Connect between the FG of both stations with the shield of the
connection cable.
On the external device side, however, follow the instruction manual
of the external device.
Be sure to use the plate terminals included with the product when
connecting the braided shield wire to the QJ71C24N-R4.
•Connect the FG of the module to the FG terminal of the power supply
module for the station including the module or to the FG terminal on
the control panel on which the programmable controller i.e., the
station including the module is installed.
•Connect nnA and nnB of each signal in the connector cable as a pair.
Correspondence of the RS-422/485 terminal block and signal location.
Shield
Module External device
SDA
SDB
RDA
RDB
SG
(FG)
(FG)
SDA
SDB
RDA
RDB
SG
FG
SG
FG
FG
SDA
SDB
RDB
RDA
POINT
1) For terminal resistor setting/connection described in this section, when the RS-
232 to RS-422 converters or similar device is used at the external device at
both ends of the circuit, a terminal resistor must be set, or connected, at the
converter.
2) When using the RS-232 to RS-422 converters to connect the external devices
and the module, use a converter that is compatible with the external device
and programmable controller CPU system configuration (1:1, 1:n, m:n).
3) Device connected to the RS-422/485 interface of the module must be
standardized as RS-422 or RS-485, including 1:n, n:1 and m:n connections.

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6. Settings for GX Developer
To use a serial communication module, set the intelligent function module
switches of GX Developer as follows:
(1) Switch 1 to 5
Set the transmission specifications and communication protocol of each
interface using the combinations of setting values for each switch with 16
bit binary data according to the following table.
Switch number Description Remarks
b15 to b8 b7 to b0
Switch 1 CH1 Communication rate setting CH1 Transmission setting Refer to (a), (b)
Switch 2 CH1 Communication protocol setting Refer to (c)
b15 to b8 b7 to b0
Switch 3 CH2 Communication speed setting CH2 Transmission setting Refer to (a), (b)
Switch 4 CH2 Communication protocol setting Refer to (c)
Switch 5 Station number setting Refer to (d)
Refer to 2) for the settings when linking the operation of two interfaces
connected to the serial communication modules.
(a) Transmission setting
ON(2)
Linked
8
Yes
Even
2
Yes
Allowed
Allowed
OFF(1)
Independent
7
No
Odd
1
No
Prohibited
Prohibited
Bit
b0
b1
b2
b3
b4
b5
b6
b7
Description
Operation setting
Data bit
Parity bit
Even/odd parity
Stop bit
Sum check code
Write during RUN
Setting modifications
CH1 side
CH2 side
b7 b6 b5 b4 b3 b2 b1 b0
The interface for which "GX Developer connection" is to be set in
communication protocol setting must be set to OFF.

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(b) Communication speed setting
Bit position Bit positionCommunication rate
(Unit: bps) b15 to b8
Communication rate
(Unit: bps) b15 to b8
50 0FH14400 06H
300 00H19200 07H
600 01H28800 08H
1200 02H38400 09H
2400 03H57600 0AH
4800 04H115200 0BH
9600 05H230400 0CH
Transmission speed of 230400 bps is available for only CH1 of the
QJ71C24N(-R2/R4).
When connecting external devices to both of two interfaces, the total of
the communication speed should be 115200bps or less (230400 bps
or less in the case of the QJ71C24N(-R2/R4)). When connecting an
external device to either of two interfaces, the maximum of 115200 bps
is available for the interface (the maximum of 230400 bps in the case
of the QJ71C24N(-R2/R4)). In this case, set 300bps for the other
interface to which no external device is connected.
Set "00H" to the interface for which "GX Developer connection" is set in
the communication protocol setting. Serial communication module will
operate at the communication speed set on the GX Developer.
(c) Communication protocol settings (CH1 side: switch 2; CH2 side: switch
4)
Set number Description Remarks
0H
GX Developer connection
(For connection to
MELSOFT products)
GX Developer communication rate and
transmission specifications are automatically.
1HFormat 1
2HFormat 2
3HFormat 3
4HFormat 4
For communication with ASCII code in the
specified form of an A compatible 1C frame or
QnA compatible 2C/3C/4C frame.
* Data communication is performed in the
message format of the set type.
5H
MC protocol
Format 5
For communication with binary code in a QnA
compatible 4C frame.
* Data communication is performed in the
message format of type 5.
6HNon procedural protocol For communication using non procedure protocol.
7HBidirectional protocol For communication using bidirectional protocol.
8HFor linked operation
setting
Set to the CH1 side when CH1 and CH2
interfaces are used in linked operation
(operated with the communication protocol of the
CH2 side).
9H
to
DH
Setting prohibited —
EHROM/RAM/switch test For self-diagnosis of the modules.
FHIndividual station
loopback test
For checking operation of each interface of the
modules.
When no external device is connected to the interface, be sure to set
its communication protocol between "0H" and "7H".
The communication protocol for the interfaces of both CH1 and CH2
can be set to "0H" at the same time.