View Full Version : Mixing different drives on the same controller

Tue 09 June 2009, 18:48
Copied from another thread:

Hey thanks guys im very happy with your comments... im working on getting a couple of used g201's and a couple month old 203v... so hopefully i wont have to buy them all for full price... i will be able to miss and match the drives right?

Tue 09 June 2009, 23:04
The G201 and G202 have the COMMON signal connection tied to +5V. The G203v driver has the COMMON signal tied to signal ground. The G201 and the G202 drives require an Active Low step pulse signal. The G203v drives require an Active High step pulse signal. In other words, without additional circuitry, you CANNOT mix G201 and G202 drives with G203v drives.

Gerald D
Mon 15 June 2009, 12:24
You can mix drives on the PMDX 122 breakout board, without additional circuitry. Instead of connecting the drive's COMMON to the marked point on the PMDX, you connect it either to 5V or GND, depending on the drive type.

Mon 15 June 2009, 13:41
A problem might occur if you mix drives. The active part of each step pulse is much shorter than the inactive part of the pulse. That means that if the COMMON signal were changed from GND to +5V, but the signal was not also inverted, the pulse timing would be off. With some devices that doesn't matter, but Mariss has written about both the minimum and maximum active pulse widths for proper operation of the drives.

I have not tested mixing drives, so I'm only passing along general information.

Gerald D
Mon 15 June 2009, 22:45
Mike, although I havn't mixed drives myself, I am going on the experience of others and advice from Steve Stallings. The pulse width concerns are taken care of in the Mach settings, where each drive can be set up independently. The default settings seem to get everyone going, so there isn't much discussion about it. But one can set "Direction Low Active Yes/No" and "Step Low Active Yes/No" as well as the pulse lengths (step and direction individually) in microseconds.

Mon 15 June 2009, 22:55

You're right. I'm still thinking as a Shopbot user. The Shopbot software doesn't have those kinds of adjustments available. If I had just turned my chair 90-degrees and switched on the Mach3 test unit, I might have re-discovered those settings.