mach3 wont reset keeps saying external emg stop requested

[dazp1976]

Here you go:- https://www.ebay.co.uk/itm/Regulated...Nrg9qr7WY2EZng

I'd get the 12v -6.5A -78w one myself. May as well for the extra few pennies. Gives you the option to add stuff.
My control box has got 60v, 36v, 24v & 5v in there!!!! If/when I need 12v I'll get a step down unit from my 24v. It's looking a bit ugh with psu's

[Clive S]

Sorry I just don't see the point.
all you are doing is just burning electricity up and putting heat into to the control box

[JAZZCNC]

I'd get the 12v -6.5A -78w one myself. May as well for the extra few pennies. Gives you the option to add stuff.
My control box has got 60v, 36v, 24v & 5v in there!!!! If/when I need 12v I'll get a step down unit from my 24v. It's looking a bit ugh with psu's

Why so many.? . . . You are just melting down the other electrics and heating the planet with all that wasted electricity.!

Regards a larger PSU for Geoff then he's only controlling a few relays and the BOB, He'll be lucky if pulling 1A total so he's still got 2.5A spare with 40W 3.5A PSU.

Geoff go with Clive's suggestion the 36W will be fine.

[dazp1976]

Why so many.? . . . You are just melting down the other electrics and heating the planet with all that wasted electricity.!

Regards a larger PSU for Geoff then he's only controlling a few relays and the BOB, He'll be lucky if pulling 1A total so he's still got 2.5A spare with 40W 3.5A PSU.

Geoff go with Clive's suggestion the 36W will be fine.

They only use what they need.
60v for the Nema 34's.
36v for the Nema 23's. (Although I now know they could probarbly go on the 60v fine).
24v for BoB spindle, estop, limits.
5v for the BoB pul/dir etc and SSR relays.

It's been added to over time and I'm still learning. In reality I could ditch the 36v as suggested above and also ditch the 5v by using a step down module from the 24v for the needed 5v. Only recently realised they existed lol. I'll wait until they fail and re-jig it all later on. That's why I got the larger than needed 24v supply for when this change occurs.

[Geoff57]

thanks everyone for your help and advice great forum ordered a psu today i will let you know how i get on
when it arrives and i have installed it in, the current situation we are all in it may be a while before i receive it
thanks again stay save thanks Geoff

[cropwell]

Just a note that automotive relay coils generally take a lot of current compared with GP electronics ones. I haven't looked at your wiring, but I wouldn't use oneanywhere but on a vehicle.

[Clive S]

Just a note that automotive relay coils generally take a lot of current compared with GP electronics ones. I haven't looked at your wiring, but I wouldn't use oneanywhere but on a vehicle.

Plus one

[Kitwn]

My controller has -3.3V, -5.0V, -12V, +3.3V, +5.0V, +12V, +24V and +36V supplies available so I win!!


There seems to be some misunderstanding in the last few posts about the significance of current/power rating of supplies. To clarify...

If you install a 12V supply rated at120W then the unit CAN deliver a current up to 10 Amps but in practice will deliver the current required by the load. If that is only 1A, the supply will deliver 1A. This is a power of 12 Watts. The power drawn from the 240V mains will be 12W divided by the efficiency of the supply. Switch mode supplies like the ones in the photographs typically have an efficiency around 85% so you will draw 12/0.85 Watts from the mains, about 14W. That gives 2W of waste heat.

If you decide to install a 12V supply rated at 240W instead, the maximum current it can supply rises to 20A. ALL the following results, including electricity used and waste heat stay the same. The only changes are that the supply will be physically bigger and cost more.

[Doddy]

Trying not to stray too far off topic, and knowing we have SMPSU engineers in here who could wipe the floor with me. Whilst Kitwn is almost completely correct in what he's saying I'd also throw in that voltage regulation can be compromised, particularly with poor design (for that read "cheap") if the presented load is completely inappropriate for the PSU rating.

The conversation about efficiency - the SMPSU efficiency would be measured at a given load - maybe 100%, maybe 80%. The efficiency at low % loads will be horrendous (consider that off load the efficiency tends towards 0). It'd be worth considering the efficiency under load and rule-of-thumb and assume that this is the worst-case thermal load and budget for that in your design.

All I'd say is that AS WELL as cost and size, I'd consider whether a PSU rating is appropriate using a wet fingered order-of-magnitude approximation - I would avoid a 1kW design for a 1W load. I'd be happy to use 1kW for something that could be expected to draw a couple of hundred watts. Common sense applies.

[Kitwn]

Doddy,
Agree with everything you've said. Though common sense isn't as common as we'd like it to be!

I was concerned that some readers trying to grapple with this stuff for the first time could get the impression that a 75W supply will waste a s**tload more power than a 40W one in the same real-world application. This just isn't the case.