[edkaar]

Hi,this is my first post on this or any other forum so bear with me if a ramble on a bit. Anyway I have just got a emco compact5 cnc which has been converted so it can be operated using its onboard controller or a laptop. The problem I have got is that when it is in the laptop mode and I start the spindle both the X and Z stepper motors begin to pulse slowly and I can't stop them doing it! Any ideas any anybody?

[tkran]

A lot of controls espescially ones that run off pc generated lpt signals cannot run properly from a laptop. From what i understand the chipset in the laptop is configured to give intermittent bursts of processor power, in order to spare battery life.They cause major interference with the transmission of signals to control. I did see somewhere it was possible to isolate or insulate signals but im not sure it is relative. It may be possible to change the chipset in the laptop,also your laptop can be made to run your software and interface with the machine controller but the real conversion would be to have a desktop chipset in the laptop.Hope this helps.

[ee_t]

Sounds like something could be floating or picking up noise? Try measuring the voltage at the inputs of your breakout board/interface. If its low/unstable, try adding a pullup resistor.

Check that you've chosen the correct parallel port address (device manager > ports). Is it an internal or external one?

http://pminmo.com/PMinMOwiki/index.php5?title=Laptops (All I needed to do was step 1 to get mach3 driver test stable).

[Fastest1]

Test the laptop pins output. If it is 5v & not 3v you should be fine. I have even seen that some got theirs to work with 3v just luck I guess. I would suspect a shielding issue on the stepper wires.