Connections for safety sensors and emergency stop devices (SS ESD) or position switches (PS) can be wired with a single or double contact. However, only double contact wiring can provide EN ISO 13849-1 category 3 or 4 levels of safety.
Double contact wiring of inputs is suitable for applications requiring EN ISO 13849-1 category 3 or 4 compliant levels of safety.
It is recommended to use this type of wiring because:
This figure shows double contact wiring:
NOTE: If less than 12 double contacts are being used, the input terminals that are not in use must be bridged.
If contacts S7 to S11 and S19 to S23 are not in use, bridge terminals S71/S62 and S112 and bridge S191/S182 to S232:
Single contact wiring is not suitable for applications requiring EN ISO 13849-1 category 3 or 4 compliant levels of safety because:
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not all errors are detected
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SS ESB or PS short circuits are not detected
In this case, pressing the SS ESD or PS does not cause the safety circuits to open, that is, there is a loss of the safety function.
This figure shows single contact wiring:
NOTE: If less than 12 contacts are being used, the input terminals that are not in use must be bridged.
If contact S18 not in use, bridge the terminals S172/S181 and S182/S191:
