Comments sought on new build: A CNC Router for RC Gliders and Planes

**njhussey** · 11-03-2015

Cheers, just thought that as long as the joins soldered ok then there's no potential at the join for a loose connection.

Next question! I'm going to get a safety relay (probably a second hand Pilz from ebay) for estops, limits, home switches etc. What's a good model to get, I've seen some Pilz PNOZ X3's which seem to fit the bill?

**routercnc** · 11-03-2015

Originally Posted by njhussey

Cheers, just thought that as long as the joins soldered ok then there's no potential at the join for a loose connection.

Next question! I'm going to get a safety relay (probably a second hand Pilz from ebay) for estops, limits, home switches etc. What's a good model to get, I've seen some Pilz PNOZ X3's which seem to fit the bill?

I'm not going to talk you out of a Pilz style relay as I looked at those as well and was impressed. However, I will mention that a level of safety interlock can be achieved with a cheap multi (4) pole relay - mine was about £8 and has the option of DIN mounting:

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One of the poles can be used to form the latch, and the rest are free to switch whatever you need downstream. However, if you don't mind the expense then the Pilz system is neat is and is what the industry seem to use.

**JAZZCNC** · 11-03-2015

Originally Posted by routercnc

I'm not going to talk you out of a Pilz style relay as I looked at those as well and was impressed. However, I will mention that a level of safety interlock can be achieved with a cheap multi (4) pole relay - mine was about £8 and has the option of DIN mounting:

I agree pilz are nice to have but not really required at DIY level. Normal relays work just as well provided they are correctly sized.

As stated a latching circuit is easily created and standard 24Vdc relays are cheap and easily sourced for any future problems. Depending on level of safety you'll still probably need a plan vanilla relay or 2 anyway as the pilz won't provide enough contacts.!