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7-9
7 Using Modbus-RTU Slave Mode
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
7-2 De
vic
e V
ariab
les f
o
r CJ-series Un
it an
d S
ystem-defi
n
ed
V
ariables (Mo
d
b
u
s-R
T
U Sla
ve Mo
de)
7
7-2
-4 De
vice V
a
riab
le f
o
r CJ-ser
ies Unit
These variables are used for data exchange [input] from the Serial Communications Unit to the CPU
Unit [input].
These variables are used to reference the port settings, the communication status, the transmission
control signal status, and the transmission error status settings of the Serial Communications Unit.
7-2-4
Device Variable for CJ-series Unit
Device variable for CJ-series Unit
Type
R/W
Name
Function
Port 1
Port 2
*_Com_UnitSta
WORD
R
Serial Com-
munication
Unit Status
Bit 01: Error log EEPROM error
Bit 00: Protocol data error
*_Com_UnitLogMemErr
BOOL
R
Error Log
EEPROM
Error
TRUE: Error log EEPROM error
FALSE: Error log EEPROM normal
*_Com_UnitPmrDatErr
BOOL
R
Protocol
Data Error
TRUE: Protocol data error
FALSE: Protocol data normal
*_P1_SysSetSta
*_P2_SysSetSta
WORD
R
System Set-
tings (*1)
Bits 12 to 15: Serial communica-
tions mode
Bits 8 to 11: Baud rate
Bit 04: Start bits
Bit 03: Data length
Bit 02: Stop bits
Bit 01: Parity (Yes/No)
Bit 00: Parity (Even/Odd)
There is no specific
device variable for
CJ-series Unit to ref-
erence the serial
communications
mode.
When you refer-
ence this setting sta-
tus, reference bits
12 to 15 of
*_P1_SysSetSta.
There is no specific
device variable for
CJ-series Unit to ref-
erence the serial
communications
mode.
When you refer-
ence this setting sta-
tus, reference bits
12 to 15 of
*_P2_SysSetSta.
Bit string
R
Serial Com-
munications
Mode
Serial communications mode
3 hex: No-protocol
6 hex: Protocol Macro
9 hex: Serial Gateway
A hex: Modbus-RTU Slave
F hex: Loopback Test
Default: 0
There is no specific
device variable for
CJ-series Unit to ref-
erence the baud
rate.
When you refer-
ence this setting sta-
tus, reference bits
08 to 11 of
*_P1_SysSetSta.
There is no specific
device variable for
CJ-series Unit to ref-
erence the baud
rate.
When you refer-
ence this setting sta-
tus, reference bits
08 to 11 of
*_P2_SysSetSta.
Bit string
R
Baud Rate
0: 9,600
3: 1,200
4: 2,400
5: 4,800
6: 9,600
7: 19,200
8: 38,400
9: 57,600
10: 115,200
11: 230,400
Default: 0
*_P1_StartBitSta
*_P2_StartBitSta
BOOL
R
Start Bits
(always 1
bit)
FALSE: 1 bit
TRUE: 1 bit
(1 bit for both FALSE and TRUE.)
*_P1_DatBitSta
*_P2_DatBitSta
BOOL
R
Data Length
(7 bits/8 bits)
FALSE: 7 bits
TRUE: 8 bits