Specifications

MODBUS Interface Modules
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AJ71UC24-S2
MODBUS interface modules
The AJ71UC24-S2 modules allow the QnA/A Series PLC to
be connected to the MODBUS network. These modules
under a MODBUS network system act as a slave station to
write and read data to/from the ACPU memory in
accordance with instructions given from a master system.
In addition to the MODBUS protocol, these modules also
support extended functions equivalent to the dedicated
protocols of standard AJ71UC24 modules. This feature gives
more flexibility of data acquisition and control by a master
system.
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Support MODBUS slave station protocols.
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Function code 1 to 21 are supported
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Two transmission modes of RTU or ASCII
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Specifications
Item Specifications
Interface RS232C: 1 channel, RS422/485: 1 channel
Transmission mode Half-duplex
Synchronous mode Start-stop synchronization
Transmission speed 300,600,1200,2400,4800,9600,19200 bps
Data format ASCII RTU
Start bit 1
Data bits 7 8
Parity bit 1 or none
Stop bit 1 or 2
Error detection Parity check (Even/ Odd)
Frame check sequence LRC CRC
Distance
RS232C: Up to 15 m (49.2 ft)
RS422/485: Up to 500 m (1,640 ft)
Current consumption (DC5V) 0.1A
Number of I/O points required 32
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Supported MODBUS functions
Code Function
01 Read coil status
03 Read holding register
05 Reset single coil
06 Reset single register
07 Read exception status
08 Loopback test
11 Fetch event counter communication
12 Fetch event communication event log
15 Force multiple coils
16 Force multiple register
17 Report slave ID
20 Read general reference-584 only
21 Write general reference-584 only
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Accessible device range
MODBUS reference Device Range
Y Y0 to 1FFF
X X0 to 1FFF
B B0 to B1FFF
M M0 to 8192
Coil F F0 to 2047
T (Coil) T0 to 2047
T (Contact) T0 to 2047
C (Coil) C0 to 1023
C (Contact) C0 to 1023
Special M M9000 to 9255
D D0 to 8191
W W0 to 1FFF
Holding register R R0 to 8191
T (Value) T0 to 2047
C (Value) C0 to 1023
Special D D9000 to 9255
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