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CJ1W-SCU

CJ-series Serial Communications Units

CJ1W-SCU

The Serial Communications Units That Enable High-speed Connections with External Devices. This unit is available for CJ/NJ controller.

Item Description
Device name Serial Communications Unit
Classification CPU Bus Unit
Model number CJ1W-SCU22 CJ1W-SCU32 CJ1W-SCU42 CJ1W-SCU21-V1 CJ1W-SCU31-V1 CJ1W-SCU41-V1
Serial
ports
Port 1 RS-232C RS-422A/485 RS-422A/485 RS-232C RS-422A/485 RS-422A/485
Port 2 RS-232C RS-422A/485 RS-232C RS-232C RS-422A/485 RS-232C
Protocol Port 1 Host Link, protocol macro, Serial Gateway, No-
protocol, NT Link, Modbus-RTU Slave, loopback
test , or 1:1 Host Link can be selected for each
port. *1, *2
Host Link, protocol macro, NT Link, or loopback test can be
selected for each port.
Unit Ver. 1.2 or later also supports Serial Gateway, no-
protocol, and 1:1 Host Link modes. (Note: The Serial Gateway
can also be executed in protocol macro mode.) *1
Unit Ver. 1.3 or later also supports Modbus-RTU slave mode.
Port 2
Number
of
mountable
Units
CPU Unit None
CPU Rack A total of up to 16 Units, including all other
CPU Bus Units. No
restrictions on the mounting location.
However, if an external interrupt task is used,
the Unit must be mounted in one of the
following slots on the CPU Rack.
CJ2H-CPU6[]-EIP CPU Unit: Slots 0 to 3
CJ2H-CPU6[], CJ2M-CPU[][] or CJ1G/H-
CPU[][]H CPU Unit: Slots 0 to 4
CJ1M-CPU[][] CPU Unit: Slots 0 to 2
External interrupt tasks will not be started if
the Unit is mounted to any other slot.
A total of up to 16 Units, including all other CPU Bus Units.
No restrictions on the mounting location.
Expansion
Rack
Data
exchange
with the
CPU Unit
Ordinary
refreshing
of software
switches
and status
Allocated 25 words of the 25 words in the CPU Bus Unit CIO Area (constant data exchange with the CPU Unit)
Transfer
from the
CPU Unit
set by the
system
Of the CPU Bus Unit DM Area, each serial port is allocated 10 words (total 20 words).
Data is transferred from the CPU Unit at the following times:
Startup or restart
Ladder instruction: STUP (237)
Port Settings Changing Flag turns ON (Auxiliary Area)
Simple Backup Function The CPU Unit's Simple Backup Function can be used to backup the Protocol Macro data in the Serial
Communications Unit to the CPU Unit's Memory Card. The backed-up data can be restored or compared.
(The Simple Backup Function can be used with the CJ1-H and CJ1M CPU Units only.)
Current consumption
*3
280mA+x 400mA 360mA+x 280mA+x 380mA 380mA+x
Weight 160g Max. 120g Max. 140g Max. 110g Max. 110g Max. 110g Max.
General specifications Conforms to general specifications for CJ Serise.

*1. Serial Gateway: The Serial Gateway can also be executed in protocol macro mode.
*2. No-protocol: An external interrupt task can be executed when data is received in No-protocol Mode. If the CJ2H CPU
       Units with unit version 1.1 or later and CJ2M CPU Units is used, the high-speed communications instructions
       (DRXDU(261) and DTXDU(262)) can also be used.
*3. The current consumption is for one Serial Communications Unit. When an NT-AL001 Link Adapter is connected to the
       Serial Communications Unit, power is supplied to the Link Adapter from the Unit. A current consumption of 0.15A
       must be added for each Link Adapter that is connected. In the above specifications, “x” indicates that 0.15A must be
       added for each port to which an NT-AL001 Link Adapter is connected to provide the required 5-V power supply.

Protocol Specifications

Host Link Specifications

Item Description
Communications mode Half-duplex (Full-duplex for slave-initiated communications)
Synchronous mode Start-stop synchronization (asynchronous mode)
Baud rate *1 RS-232C port and RS-422A/485 ports:
1,200/2,400/4,800/9,600/19,200/38,400/57,600/115,200/230,400 bps *2
Default setting: 9,600 bps
Communications distance *1 RS-232C port: 15 m max. *3
RS-422A/485 Port:
CJ1W-SCU[]1-V1
500 m max. (total cable length: 500 m max., T-branch branch lines: 10 m max.)
CJ1W-SCU[]2
1,200 m max. (total cable length: 1,200 m max., Multidrop connections are possible. However, maximum
cable length is 500 m if the NT-AL001 is used for RS-422A-485 connections.)
Connection configuration RS-232C port: 1:1 (1:N (N = 32 Units max.) is possible using an Converting Link Adapters.)
RS-422A/485 port: 1:N (N = 32 Units max.)
Number of connected Units 32 Units max. (unit numbers 0 to 31; unit number 0 is set for 1:1 connection)
Frame structure C-mode commands Header: @, address: (host link unit number) 0 to 31 (BCD), data: header code +
text, error check code: FCS, terminator: * +CR
FINS commands Header: @, address: (host link unit number) 0 to 31 (BCD), data: header code
(always "FA") + FINS header + FINS command + text, error check code: FCS,
terminator: * +CR
Error check codes Vertical parity: Even, odd. or none
FCS (horizontal parity converted to ASCII)
Command flow and support Command flow Commands Contents
Host computer to
Controller
C-mode commands 1:1 or 1:N communications with directly connected
Controller *4
FINS commands
(in Host Link protocol)
1:1 or 1:N communications with directly connected
Controller.
Controller to host
computer
FINS commands
(in Host Link protocol)
Communications using SEND(090), RECV(098), and
CMND(490) from CPU Unit. *5

*1. Confirm the baud rates and communications distance supported by connected devices.
*2. The CJ1W-SCU[]2 is required for communications at 230,400 bps.
*3. The maximum cable length for RS-232C is 15 m. The RS-232C standard, however, does not cover baud rates above
       19.2 Kbps. Refer to the manual for the device being connected to confirm support.
*4. The specified frame format must be prepared on the host computer and then sent.
*5. The host computer must interpret the commands and return a response in the correct format.
       Connection between the host computer and Controller must be 1:1.

Protocol Macro Function Specifications

Item Description
Number of
protocols
20 max. Can be created and registered with the Protocol Support Tool (CX-Protocol).
Number of
sequences
1,000 max.
Per protocol Number of sequences 60 max.
Number of messages 300 max.
Number of reception
matrixes
100 max.
Sequence execution condition Using the CPU Unit's PMCR (260) instruction (specifying the sequence number)
Communications mode Half-duplex or full-duplex
Synchronous mode Start-stop synchronization (asynchronous mode)
Baud rate *1 RS-232C port and RS-422A/485 ports:
1,200/2,400/4,800/9,600/19,200/38,400/57,600/115,200/230,400 bps
Default setting: 9,600 bps *2
Communications distance *1 RS-232C port: 15 m max.
RS-422A/485 port:
CJ1W-SCU[]1-V1
500 m max. (total cable length: 500 m max., T-branch branch lines: 10 m max.)
CJ1W-SCU[]2
1,200 m max. (total cable length: 1,200 m max., Multidrop connections are possible. However,
maximum cable length is 500 m if the NT-AL001 is used for RS-422A-485 connections.)
Connection configuration RS-232C port: 1:1 (1:N (N = 32 Units max.) is possible using a Converting Link Adapter.)
RS-422A/485 port: 1:N (N = 32 Units max.)
Number of connected Units 32 Units max. (unit numbers 0 to 31; unit number 0 is set for 1:1 connection)
Maximum
number of
data
exchange
words
between
Controller
and protocol
macro
function
Operand setting 250 words Including the word that specifies the number
of words (1 word)
Link word setting 500 words O1, O2, I1, and I2: 500 words total
Direct setting 500 words Maximum number of words per data attribute
Sequence
contents
(step
common
parameters)
Number of steps per
sequence
16 max.
Transmission control
parameters
X-on/X-off flow, RS/CS flow, delimiter control, or contention control, and modem control can
be selected.
Response notification
method (operand)
Scan notification: Writes the receive data to I/O memory during CPU Unit scanning.
Scan method (fixed) Support
Interrupt notification Not support
Interrupt notification for reception case number Not suppprt
Monitoring time during
send/receive
processing
Receive wait, receive completion, or send completion can be monitored.
Setting range: 0.01 to 0.99 s, 0.1 to 9.9 s, 1 to 99 s, or 1 to 99 minutes
Link word setting Area in which data is exchanged between the CPU Unit and the Serial Communications Unit
during Communications Unit refreshing.
Two areas are possible for each device: An area for storing receive data and an area for storing
send data. *3
Step
contents
Commands Send only (SEND), receive only (RECV), send and receive (SEND&RECV), wait (WAIT), reception
buffer clear (FLUSH), ER-ON (OPEN), or ER-OFF (CLOSE)
Repeat counter 1 to 255 times
Retry count 0 to 9 (Only when the command is SEND&RECV)
Send wait time 0.01 to 0.99 s, 0.1 to 9.9 s, 1 to 99 s, or 1 to 99 minutes
(Only when the command is SEND or SEND&RECV)
With or without
response write
(operand)
When receive processing is completed (when the receive data is stored in the area specified in
the 4th operand of the PMCR(260) instruction), whether or not to store the received messages
can be selected.
Next processing When a step has ended normally, End (sequence completed), Next (proceed to the next step No.),
Goto (go to the specified step No.), or Abort (interrupt the step and terminate that sequence)
can be selected.
Error processing When a step has ended abnormally, End, Next, Goto, or Abort can be selected.
Send message Data sent to the specified address when the
command is SEND or SEND&RECV.
Consists of a header, address, length, data,
error check code, and terminator.
Receive message Data sent from the specified address when the
command is RECV or SEND&RECV.
Reception matrix When the command is RECV or SEND&RECV,
sets the expected receive messages (15 max.),
and switches to the next processing according
to the message received.
Specifies the receive messages and the next
processing for each of cases No. 00 to No.
15. Of the maximum 16 cases, one case must
be set as "Other" in the receive messages
(in addition to the set receive messages).
Message
unit
contents
Header and
terminator
data
attributes
Constant ASCII data, hexadecimal data, or control code
Data
attributes
of
addresses
and data in
send/
receive
messages
Constant ASCII data, hexadecimal data, or control code (with an address, no control code is possible)
Variable No conversion, conversion to ASCII data, or conversion to hexadecimal data
(the read/write direction can be specified)
Designation
method
(X, Y)
X: Effective address (where read from, or where written to)
Y: Data size (1 to 1,000) *4
X Word
designation
Word read
(I/O memory
to send data)
Specify using the
3rd operand of the
PMCR(260) instruction.
Set leading address
+ n (The linear
expression aN + b,
including repeat
counter N, is also
possible for n.)
Specify using a link
word.
I/O memory direct
designation
Word write
(receive data
to I/O memory)
Specify using the
4th operand of the
PMCR(260) instruction.
Specify using a link
word.
I/O memory direct
designation
Wild card * Any data or address can be received
(only in receive messages)
Repeat counter N
Y Linear expression
including repeat
counter
aN+b a: 0 to 1000; b: 1 to 1000
N: Repeat counter value
Wild card * Can be received regardless of the length
(only in receive messages)
Word designation Word read
(I/O memory
to send data)
Specify using the
3rd operand of the
PMCR(260) instruction.
Set leading address
+ n (The linear
expression aN + b,
including repeat
counter N, is also
possible for n.)
Specify using a link
word.
I/O memory direct
designation
Error check codes LRC, LRC2, CRC-CCITT, CRC-16, SUM, SUM1, and SUM2 can be calculated.
Maximum length of
send/receive
messages
1,000 bytes. (A maximum length between 200 and 1,000 bytes can be set in the Setup Area.)
Maximum number of
data attributes
registered in one
message
96 attributes *5
Maximum number of
write data attributes
registered in one
message
30 attributes *6
Trace function *7 A total of up to 1,700 bytes (characters) of time-series data can be traced in send and receive
messages.
Changes to the step No. and control signals such as RS and CS can also be traced.

*1. The baud rate and the communications distance sometimes depend on the remote device.
*2. A baud rate of 57,600 bps can be selected when using Unit Ver. 1.2 or later (115,200 bps is not possible). The CJ1W-
       SCU[]2 is required for communications at 115,200 or 230,400 bps.
*3. Unit Ver. 1.2 or later supports continuous I/O refreshing in addition to the previous on-request I/O refreshing.
*4. The data size is the number of bytes on the transmission path.
*5. The CX-Protocol can be used to register up to 96 attributes per message.
*6. A macro syntax error will occur when the protocol macro is executed if more than 31 write attributes are registered in
       one message.
*7. The CPU Unit is set to the RUN/MONITOR mode. (MONITOR mode is not available with the NJ-series CPU Units.)
Note: When using 2-wire RS-422A/485 communications in Protocol Macro Mode, set only modem controls for the send
          control parameters, and do not use RS/CS flow controls.

Serial Gateway Specifications

Item Description
Conversion source FINS commands (received through network (including Host Link FINS) or CPU bus)
Conversion functions The received FINS command sent to the Unit's serial port is converted according to the FINS command code as follows:
2803 hex: FIN header removed and converted to Compo-Way/F command.
2804 hex: FIN header removed and converted to Modbus-RTU command.
2805 hex: FIN header removed and converted to Modbus-ASCII command.
The converted command is sent to the serial port.
When the received FINS command is sent to the Unit (user-specified FINS command code), the FINS command is
enclosed in a Host Link header and terminator.
Converted format CompoWay/F commands
Modbus-RTU commands
Modbus-ASCII commands
Host Link FINS commands
Enabled serial
communications mode
Serial Gateway mode or protocol macro mode
Queuing functions Up to five FINS commands can be converted and then queued for processing.
Protocol macro
execution processing
When a FINS command is received during protocol macro execution, the Serial Gateway is executed using an interrupt between steps in the communications sequence. If the next step is a RECEIVE command, the Serial Gateway will not be executed until the next step. For other conditions, the interrupt is executed immediately. *1
Response timeout
monitoring
The time is monitored from when the message is converted into the specified protocol using the Serial Gateway
until the response is received (in Serial Gateway mode or protocol macro mode).
Default: 5 s (setting range: 0.1 to 25.5 s) *2
Send start timeout
monitoring
The time is monitored from when the FINS command is received until it is converted into the specified protocol and
starts to be sent (in protocol macro mode only).
Default: 5 s (setting range: 0.1 to 25.5 s) *3
Send delay The time can be set from when the message is converted into another protocol using Serial Gateway conversion
until the data is actually sent. (Serial Gateway or protocol macro mode)
Default: 0 s (setting range: 0.01 to 300.00 s)

*1. The reception buffer is cleared during Serial Gateway execution.
       The Serial Gateway can be prohibited in protocol macro mode by turning ON the Serial Gateway Prohibit Switch in the
       CIO Area.
*2. When a timeout occurs, the FINS end code (0205 hex: Response timeout) is returned to the source of the FINS
       command and a response is received after a timeout occurs.
*3. When a timeout occurs, the FINS end code (0204 hex: Remote node busy) is returned to the source of the FINS
       command. The send processing will not be executed and the received FINS command will be discarded.

No-protocol Specifications

Item Description
Communications mode Full-duplex
Baud rate *1 RS-232C port and RS-422A/485 ports: 1,200/2,400/4,800/9,600/19,200/38,400/57,600/115,200/230,400 bps *2
Default setting: 9,600 bps
Communications
distance *1
RS-232C port: 15 m max.
RS-422A/485 port:
CJ1W-SCU[]1-V1
500 m max. (total cable length: 500 m max., T-branch branch lines: 10 m max.)
CJ1W-SCU[]2
1,200 m max. (total cable length: 1,200 m max., Multidrop connections are possible. However, maximum cable
length is 500 m if the NT-AL001 is used for RS-422A-485 connections.)
Messages
(communications
frame structure)
Set either of the following types in the Setup Area in the allocation DM Area.
1. Data only (without start code and end code)
2. Start code + data
3. Data + end code
4. Start code + data + end code
5. Data + CR + LF
6. Start code + data +CR + LF

Set in allocated DM Area
(The start code can be included by setting it to between 00 and FF hex, and the end code can be included by
setting it to between 00 and FF hex. To exclude the end code, set the number of receive data bytes.)
Start code None or 00 to FF hex
End code None, 00 to FF hex, or CR + LF
Number of receive data
bytes during reception
Set the number of receive data bytes between 1 and 256 bytes (according to the DM
Area settings) when frame structure 1 or 2 above is used.
Sending messages CJ: TXDU (256) instruction *3
NJ: SerialSend instruction
Receiving messages CJ: RXDU (255) instruction *3
NJ: SerialRcv or SerialRcvNoClear instruction *4
Maximum message
length
Sending and receiving: Up to 259 bytes including the start code and end code (up to 256 bytes excluding
start/end codes)
Data conversion No conversion
Communications
protocol
None
Message delay time CJ:
When the TXD (236), TXDU (256) instruction is executed, after the send delay time, the data is sent from the
port. *3
0 to 300 s (0 to 300,000 ms)
(Can be set in 10-ms units depending on the DM Area settings)
NJ:
When the SerialSend instruction is executed, after the send delay time, the data is sent from the port.
0 to 300 s (0 to 300,000 ms)
(Can be set in 10-ms units: Set in System Studio or by using a device variable for CJ-series Unit.)
Receive counter The number of data bytes (0 to 256) received at the port can be counted.
Reception buffer clear
timing
CJ1W-SCU[]1-V1
The reception buffer is cleared immediately after executing the RXD(235)/RXDU(255) instruction
CJ1W-SCU[]2
With the DRXDU (261) instruction, you can specify whether the reception buffers will be cleared or not in a setting
in the DM Area words allocated to the Unit. *3
NJ
SerialRcv instruction: After reading the receive data
SerialRcvNoClear instruction: When the receive data size variable (Size) is set to 0 *4

*1. The baud rate and the communications distance sometimes depend on the remote device.
*2. The CJ1W-SCU[]2 is required for communications at 115,200 or 230,400 bps.
*3. The DTXDU (262) and DRXDU (261) instructions can be used only when a CJ1W-SCU[]2 Serial Communications Unit
       is connected to the CJ2H CPU Units with unit version 1.1 or later and CJ2M CPU Units.
*4. A Serial Communications Unit with unit version 2.1 or later, a CPU Unit with unit version 1.03 or later, and Sysmac
       Studio version 1.04 or higher are required to use the SerialRcvNoClear instruction.

Modbus-RTU Specifications

Item Description
Mode Modbus-RTU slave mode *1
Baud rate 1,200/2,400/4,800/9,600/19,200/38,400/57,600/115,200/230,400 bps *2
Default: 19,200 bps
Data length 8 bits
Parity Odd, even, or none
Default: Even
Stop bits Odd or even parity: 1 bit
No parity: 2 bits
Address setting range 1 to 247 (broadcasting: 0)
Frame format Slave address: 1 byte
Function code: 1 byte
Data: 0 to 252 bytes
CRC code: 2 bytes

*1. Modbus-ASCII mode is not supported.
*2. The CJ1W-SCU[]2 is required for communications at 230,400 bps.

Supported Commands

Function code
(hexadecimal)
Function Modbus name
1 Reads multiple bits from the CIO, Work, Holding, or Auxiliary Area of I/O memory. Read Coils
2 Reads multiple bits from the CIO Area of I/O memory. Read Discrete Inputs
3 Reads multiple words from the DM or EM Area of I/O memory. Read Holding Registers
4 Reads multiple words from the CIO, Work, Holding, or Auxiliary Area of I/O memory. Read Input Registers
5 Writes a bit in I/O memory. Write Single Coil
6 Writes a word in the DM or EM Area of I/O memory. Write Single Register
8 Executes an echoback test. Diagnostic
0F Writes multiple bits in I/O memory. Write Multiple Coils
10 Writes multiple words in the DM or EM Area of I/O memory. Write Multiple Registers