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CJ1W-SRM21 Master Unit for CJ-series PLCs
Section 4-3
5.
Connect the communications cable connector to the Master Unit, as
shown in the following diagram.
6.
Tighten the connector screws and secure the connector to the Master Unit.
The tightening torque is 0.25 to 0.3 N
⋅
m.
4-3-4
I/O Allocations
CJ-series Master Units are allocated words for Slave I/O data and status flags
in the Special I/O Unit Area of the Master. Words in the Special I/O Unit DM
Area is allocated for the Slave registration function and communications stop
mode.
Allocations and Master
Unit Settings
The areas used by the Master Unit depend on the Master Unit settings, as
shown in the following table.
Slave Allocations
Slaves are allocated in the Special I/O Unit Area as shown in the following dia-
gram. In CompoBus/S Systems, node numbers of Input Slaves and Output
Slaves are treated separately so the same number can be allocated.
BS+
BDH
BDL
BS
−
BS+
BS
−
Setting at Master
Unit
Status
Affect on allocation
Usable node number
settings (DIP switch
pin 1)
OFF
Uses 10 words (words for one unit) from the Spe-
cial I/O Unit Area as follows:
Output: 4 words, input: 4 words, status: 2 words.
(100 words are allocated in the Special I/O Unit
DM Area)
ON
Uses 20 words (words for two units) from the
Special I/O Unit Area as follows:
Output: 8 words, input: 8 words, status: 4 words.
(100 words are allocated in the Special I/O Unit
DM Area)
Special I/O Unit num-
ber setting (rotary
switch)
n
First word of the area used in the Special I/O Unit
Area is CIO 2000 + (n
×
10) words
First word of the area used in the Special I/O Unit
DM Area is (n
×
100) words