Quote Originally Posted by gabi68 View Post
I keep asking about the relay because DM542 has - Pul+, Pul-, Dir+, Dir-, Ena +, Ena-, Gnd and+24VDC. According to your diagram I should have a relay with 7 inputs. Where I can find something like that? Or I got this wrong....
You use Arduino for the operation you want to be executed by your lathe. I don't need this. I only need to use safely 2 stepper motors (alternatively) with a one stepper driver.
No. All you need is a 4-pole relay. Pul -, Dir - and Ena - are all connected together to GND. You are controlling only Step, Dir and Ena.

I know you don't need the Arduino. The Arduino is generating the pulses I need for the lathe operation, but that's just for your information on my use. All you need is what my drawing shows, i.e. a 4 pole relay and a switch. The one I am using is DS4E-M-DC5V made by SDS. It is a low power signal relay, fast and requires very little current, but it is obsolete so maybe hard to find. Anyway, there are plenty small signal relays which can be used, and it is not critical that all the contacts are in the same casing, so you can use 4, 2 or 1 relay depending on what you find. Here is an example which works also, but you need to wire it:

https://www.amazon.se/Yizhet-kanal-r...03086861&psc=1