How reliable are safety relays?

[cropwell]

Like this one ?

[Neale]

Similar but different! No, mine is the older version, big and clunky in appearance.

I was thinking about it overnight and realise that the only reason I used it was because I needed a relay of some kind - NVR-type function, multiple contacts to switch driver PSU, signal motion controller, feed enable inputs on drivers - and I stumbled across this one cheap. In practice, I could get the same functionality minus the "fail safe" aspect for a lot lower price and had I not found the Pilz, that's what I would have done. So I might as well do that now! There are plenty of plug-in relays available new with DIN rail fitting bases that would only need trivial wiring changes.

In fact, two such relays with latching contacts cross-connected and contacts wired in series or parallel would provide similar capability to the Pilz in this situation but I don't feel I need to go that far...

[JAZZCNC]

I've had 2 Pilz relays do similar things, both bought used, so can't know how used or worn. But now I don't bother anymore and just build my own latching safety circuit using vanilla ice cube relays, they are cheap and easily replaced if they go faulty. Which to be honest I rarely have problems with, even with the cheap Chinese relays.