3 Axis CNC router

[Neale]

Joe,

couple more comments!

Main one is that you have two LED indicator lamps wired in series off the 24V supply, switched by the safety relay. I'm assuming that these are both 24V LED lamps. Ideally, you should have them wired in parallel rather than series. That is, take the wire from the safety relay to both lamps, and a wire from ground to both lamps. They will probably work the way you have them but won't be at full brightness.

The other point is about the switch to the stepper PSU. What I have done on my machine is take a 24V feed from one of the safety relay contacts (in fact, the one that feeds the panel lamps as above) to the PSU. In your case, if you like, you could take this via the switch as well (my machine does not have a switch in this position). Your system will work OK, but the way I have it, if you hit an e-stop then not only do you signal the CSMIO via the e-stop digital input pin, you also remove power from the steppers. Actually, I also use the N/C contact to supply 5V to the enable inputs on the stepper drivers as well; with the safety relay de-energised, this effectively disables the stepper drivers. So, on e-stop, you tell the CSMIO to stop sending pulses, you remove power from the drivers, and you also disable the drivers explicitly. You might not want to bother with the last point here, but taking the 24V from the safety relay would be a trivial change on your diagram and adds a small (although probably unnecessary) additional safety factor.

[JoeHarris]

Joe,

couple more comments!

Main one is that you have two LED indicator lamps wired in series off the 24V supply, switched by the safety relay. I'm assuming that these are both 24V LED lamps. Ideally, you should have them wired in parallel rather than series. That is, take the wire from the safety relay to both lamps, and a wire from ground to both lamps. They will probably work the way you have them but won't be at full brightness.

The other point is about the switch to the stepper PSU. What I have done on my machine is take a 24V feed from one of the safety relay contacts (in fact, the one that feeds the panel lamps as above) to the PSU. In your case, if you like, you could take this via the switch as well (my machine does not have a switch in this position). Your system will work OK, but the way I have it, if you hit an e-stop then not only do you signal the CSMIO via the e-stop digital input pin, you also remove power from the steppers. Actually, I also use the N/C contact to supply 5V to the enable inputs on the stepper drivers as well; with the safety relay de-energised, this effectively disables the stepper drivers. So, on e-stop, you tell the CSMIO to stop sending pulses, you remove power from the drivers, and you also disable the drivers explicitly. You might not want to bother with the last point here, but taking the 24V from the safety relay would be a trivial change on your diagram and adds a small (although probably unnecessary) additional safety factor.

Appreciate the help! I was actually away last week - hence the hand drawn diagrams and had totally messed that bit up! Just amended it which naught make a bit more sense.