Signals and PLC · Glossary
What is an Interposing Relay?
isolation between PLC and loadSignals and PLC
An interposing relay is a relay driven by a PLC output that switches a load the PLC cannot drive directly.
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Interposing Relay Explained
It isolates the PLC from high current, high voltage or different supply systems, such as motor starter coils or 230 V AC solenoids.
Interposing relays also mark a clear boundary between control panel and field circuits.
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Calculators for Interposing Relay
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Frequently Asked Questions
What is an Interposing Relay?
An interposing relay is a relay driven by a PLC output that switches a load the PLC cannot drive directly.
Why use a relay instead of a bigger output?
It isolates systems and is cheap to replace if the load damages it.
Do relays slow response?
Slightly, by a few milliseconds of operate time.
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A practical guide on instrumentationblog.in with more detail on interposing relay and how it is applied on real plants.
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