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Output Wiring Precautions Observe the following precautions to protect the PC’s internal components.
Output Short Protection
The output or internal circuitry might be damaged when the load connected to an
output is short-circuited, so it is recommended to install protective fuses in the
output circuits.
Inductive Loads
When connecting an inductive load to an input, connect a surge protector or
diode in parallel with the load.
The surge protector’s components should have the following ratings:
OUT
COM
CPM1 relay output
Surge protector
The diode should satisfy the following requirements:
Peak reverse-breakdown voltage must be at least 3 times the load voltage.
Average rectified current must be 1 A.
OUT
COM
CPM1 relay output
Diode
3-4-5 Conformance to EMC Directives
Each CPM1 PC conforms to the Common Emission Standards (EN50081-2,
established in June 1993) of the EMC Directives. However, the noise generated
when the PC is switched ON or OFF using the relay output may not satisfy these
standards. In such a case, a noise filter must be connected to the load side or
other appropriate countermeasures must be provided external to the PC.
Countermeasures taken to satisfy the standards vary depending on the devices
on the load side, wiring, configuration of machines, etc. Following is an example
of a countermeasure for reducing the generated noise.
Countermeasures
Countermeasures are not required if the frequency of load switching for the
whole system with the PC included is less than 5 times per minute.
Countermeasures are required if the frequency of load switching for the whole
system with the PC included is more than 5 times per minute.
Refer to EN50081-2 for more details.
Wiring and Connections
Section 3-4
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