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Entry type: FAQ Entry ID: 109741649, Entry date: 05/03/2017
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Short circuit fault during safety-related control of 3SE53 position switches with LEDs

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This entry contains information regarding short circuit faults during the safety-related control of 3SE53 position switches with LEDs

QUESTION:

When the solenoid of a 3SE53 position switch with LED is safely controlled by an F-CPU (with a safe output), a "short circuit fault" error message occurs in the controller.
What can be done here?



ANSWER:

The safety-related control of the solenoid of a 3SE53 position switch with tumbler and LED results in a short circuit (LED at contact 12 causes a cross-circuit via the E2 connection of the solenoid coil), as the negative terminal of the safety-related output is not the same as that of the voltage supply applied to terminal 11.

Solutions:
- Deactivate short-circuit fault messages in the software.
- Do not control the solenoid in a safety-related manner (i.e. using a standard output with the voltage at terminal 11).
- Do not use the LEDs, i.e. do not apply a voltage to terminal 11.
- Use a position switch without LEDs, e.g. 3SE5312-0SB11 instead of 3SE5312-1SB11.
- For the safe output module, instead of +/-, it is also possible to perform safety-related control via + only. However, the negative terminal must be identical to that of the control voltage for the LEDs.

Please find a   circuit diagram (105,5 KB) attached for the 3SE53 position switch with LED indicator.
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