Sensor, Relay and back EMF - 24VDC??

[gerard]

Hi,

I am using an ifm sensor to detect a product coming down the line in our factory. I have connected this sensor in such a way as to energise a 24VDC Relay. No PLC involved here. It does the job perfectly and I am happy with it.
Anyhow, I was just wondering if I should be using a surge suppressing diode across the coil to prevent back EMF when the coil opens and the magnetic field collapses?
If the back EMf was to damage the sensor, would it have done this straight away? Has anyone done anything like this out there?

Regards,

 

[davelerave]

i remember a question or two on this recently
a search may dig it up

 

[Knobhead]

Fitting a reverse bias diode at this late stage won’t do any harm. For the sake of a couple of pence I’d fit one.

 

[pmac10]

ive done this hundreds of times across many lines and never used surge surpression, the only benefit i can see is faster operation from removing the back emf but i dont think you would notice