Ab 1734-ib8s

Hi all
I'm working in a new factory checking and upgrading safety on machines. The have installed a new machine and I have been asked to validate the safety of it and have been working through there validation sheet and it asks to bridge 24v to the safety inputs to simulate a fault and to bridge 0v to the inputs as well. I have been reading the manual but have not yet found a yes or no answer to wether I should do this. Will I course damage to the units if I do? thanks all

It's safe to do. The inputs normally switch from 24V to 0V.

The safety validation checks to see if shorts can be detected using the pulses on the test outputs.

Thank you. In shorting 24v to the inputs not the test pulse and 0v to the input while there is the test pulse going to the unit. Can you direct me to where it is written its ok thanks

I don't think you'll find it written explicitly anywhere, but you can configure the inputs to not worry about using a test pulse and just wire them straight to 24VDC. You might do this when using a light curtain for example, or if you were using a safety input for a non-safety related application. The input card won't know any different whether the 24VDC is coming from a light curtain, a limit switch or a piece of wire poked onto the DC power supply.

As for shorting it to zero volts, that again is not much different to turning the input off. I'd be more worried about the impact on your power supply and whatever device is feeding that input (e.g. magnetic guard switch) than I would be about the input card.

I do those tests, and all the others, quite frequently. I should probably mention that my current tally of blown up safety devices while conducting safety validations stands at three guards switches and a safety relay (and about two dozen fuses), but if you want them to sign on that dotted line, you've got no other choice!