Issues with stepper motors losing power

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Originally Posted by A_Camera

I am not sure what you mean by "The most common config is the opposite of yours"... My system works just like are describing. Perhaps you misunderstood what I wrote. Disable = no holding torque Enable = Holding torque the way I see it. The signal can be active low or active high, depending on some other things, but that's a different thing.

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Excuse the pun, I think we are getting our wires crossed here.! What I meant was that the standard setup is that the drives have holding torque if the enable is NOT used and if the enable is used then holding torque is dropped when the state changes. The way you described it your drives are set so they need the enable signal to engage the torque, this is opposite to standard setup is what I meant.

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Originally Posted by A_Camera

You were saying earlier: "The enable won't drop the holding torque, it will only disable the drive outputs so they don't spin, they will still be locked"

The Enable signal controls the holding torque. If the Enable changes state (goes from low to high or high to low) it will enable or disable the driver which will apply or drop the holding torque. On most drivers, if the Enable is not connected (floating) the holding torque is applied and the driver is enabled. The motor is locked only when there is a holding torque (driver enabled). If the driver is disabled and there is no holding torque, the motor can't spin, not even if you apply step pulses. When the driver is enabled the motor is on holding torque but starts spinning as soon as step pulses are applied.

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Yes that is the common way it works but it's not exclusive and some drives have the ability to maintain the holding torque when the enable changes it states, they just stop movement, this helps in applications like Z-axis, etc where don't want it to drop when an E-stop occurs, etc. Many servos and some closed-loop stepper drives offer this option with a parameter change.

Hi Guys

Sorry I haven't replied sooner but I've been away for a few days and have also been working on a solution. Thanks for all the responses and debates that ensued!

I am now glad to report that everything is working well. It's a bit of a saga but there were a few things wrong. The other two Dell pcs I was using already had a printer ports installed (by Dell). I don't know if by putting the Moschip pci board in was causing a conflict? I also noticed that even with the cnc controller unplugged from the pc, Mach 3 was not working properly. Somehow it is corrupt. It was a version I got with the Chinese machine. Can't remember if it came as a download or a disc but I didn't have either to hand.

I decided to buy a new motherboard for the old original pc that I knew worked prior to buggering it up last winter. Once I had it configured and reinstalled the PCI board and downloaded the demo version of Mach 3 everything started working perfectly. Don't know why but the address for the Moschip PCI board had changed with the new motherboard but once I figured this out - bingo!

The only issue I have now is Mach 3 in demo mode only which only gives me 500 lines of movement. I could spring a few quid for a proper UK version of Mach 3 but I've been reading up on LinuxCNC and wondered how this stacks up against Mach 3 and how similar is it? Will download a copy and give it a whirl

cheers again for everyone's input

Steve

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Originally Posted by Steven W

Steve

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Did you keep all the old Mach files / hdd from the pc or did you wipe it?.
There'll be a file in the old mach folder called Lic.
This is the license file. You just copy it to the new mach folder.

If your old HDD is alive copy from c:\Mach3 folder the following:
Mach1lic.dat
<yourmachineprofile>.xml
whole folder:
C\Mach3\macros\<yourmachineprofile>
C:\Mach3\Brains

OR

whole C:\Mach3 folder and rewrite it on new machine (if Mach version is tha same)

Thanks for that info. I still had the old copy of Mach 3 on my pc. Downloaded the new Mach 3 dragged the lic file over and all working good again

Cheers Steve