Chapter 6. Communication Function
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6.3.2 How to use special module function block
1) Setting the mother station
The slave can’t have a user program. It is remote I/O device that uses the PLC CPU’s user
program and communication function. Before system configuration, set the mother station of the
slave. Mother station no. can be done by using the inner decimal switch of slave module. Mother
station acts as a master when executing the high-speed link and slave special module access FB
service.
[Table 6.3.2] indicates whether slave service operates or not according to PLC mode of mother
station. Since slave operates according to mode of mother station like the follow table, in case
other station except mother station accesses the slave special module, it may cause error.
Special module should be accessed by mother station.
[Table 6.3.2] Slave operation according the mother PLC mode
CPU MODE
Slave HS link
[note]
Slave special module
access
Slave I/O refresh
RUN
○
○
○
STOP
○
X
○
PAUSE
○
○
○
DEBUG
○
○
○
2) Program
Special module control through slave uses communication function between master and slave.
So the user should consider the reliability of communication when programming.
[Figure 6.3.2] is system configuration. Two masters are equipped at the GM3 CPU and one master
controls two slaves. A/D module (4 channels) is equipped at the no.1 slot of slave station no.3 and
D/A module (2 channels) is equipped at the no.2 slot of slave station no.4.
High-speed link operates according to ‘Link Enable’ of mother station.
