[santydofus2014]

Hello.
I have got a CNC mill from 1997 used at auction, but I'm stuck on a basic startup error.
I get the " Relay ext. DC Voltage Missing " error, although the e-stop is not pressed, air is 6bar+, oil level is good, no limit switches are physically triggered, etc.

I have only found one PSU here: the big black/green box in the pictures. Shouldn't there be two 24v power supplies?

Also, how can i start to diagnose problems in this controller? i have had trouble finding any electrical diagrams online for the controller.

Would it be a good idea to start looking into the orange safety relay, and try to figure out if something is triggering it? How can i approach this route if viable?

Or, about the controller connections, where can i check for a missing voltage?

I have seen threads similar to this on the forums, but i have failed to find a solution although i've tried most of the things listed.

[jaideepshinh]

Hi,
Are you familiar with the general operation of Heidenhain controls? Based on this we here would be able to guide you on the way forward.

Relay ext. DC voltage missing isn't actually an error. It means you need to press and hold the machine ON button for about 1 second. (usually a white or green round button on the main keyboard). I am assuming you have done this and are still facing the same issue. Please check the E-STOP circuit diagram in the electrical manuals- if the ESTOP buttons are released but the ON button isn't responding, then you need to see which part of the circuit is causing the issue. check if any ATC or door interlocks are holding you up

best of luck!
Jaideep

[steryd]

It may also mean that U are on some hardware limit that holds safety circuit off.
Usuallu it is Z limit cause this axis can move a little with power off.
I had this problem lots of times with my machines.u need to release the limit switch that is touched.
Or other thing- pendant if there was one it is also a part of safety circuit (it has e-stop on it) and it has to be connected or at least e-stop pins on the socket have to be shorted.