Sensor and pre-actuator power supply servo control
(Original Document)
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How to set up servo control
It is recommended that servo control of the different power supplies is set up in the following sequence:
Step
Action
1
Switch on the power supply to the PLC and the inputs (sensors), using the contactor KM (see diagram).
2
If the PLC is in RUN mode and running on AUTO, switch on the output power supply (pre-actuators), using the contactor KA. This is controlled by the alarm relay contact in each power supply.
Safety standards
Before restarting the installation following a stop (caused by a power outage or an emergency stop), safety standards require authorization to be given by the operator.
The MANU/AUTO switch makes it possible to force outputs from a terminal, when the PLC is in STOP mode.
Example 1
PLC station supplied by alternating current:
Example 2
PLC station supplied by direct current: