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1 Introduction
1-18
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
*1
The baud rate and the communications distance sometimes depend on the remote device. Confirm them in the
operation manuals for the connected devices.
*2
When you use 2-wire RS-422A/485 communications in Protocol Macro Mode, set only modem controls for the
transmission control parameters, and do not use RS/CS flow controls.
*3
The data size is the number of bytes on the transmission path.
*4
The CX-Protocol can be used to register up to 96 attributes per message.
*5
A macro syntax error will occur when the protocol macro is executed if more than 31 write attributes are regis-
tered in one message.
Message unit
contents
Data attributes
of addresses
and data in
send/receive
messages
Vari-
ables
Y
Linear expres-
sion 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 mes-
sages)
Word designa-
tion
Read word
(memory used
for CJ-series
Units to send
data)
Specify by the
input variable:
SrcData of the
SendPMR
instruction.
Set leading
a n
(The linear
expression aN
+ b, including
repeat counter
N, is also pos-
sible for n.)
Specify the
area by a link
word.
Directly spec-
ify the memory
used for CJ-
series Unit
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 regis-
tered in one message
96 attributes (*4)
Maximum number of
write data attributes
registered in one mes-
sage
30 attributes (*5)
Trace function
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.
Item
Description