Re: fickle y-axis

Hi,

Did some detective work - tried swapping motor cables around. Turned
out that the problem followed the "y-axis" cable. One of the wire was
loose, in fact, eventually broked loose from the soldered pin.
Changing to a new cable solved the problem.

However, I am puzzled as to how a bad cable can lead to erratic
behaviour, that is when a movement in the positive direction is
commanded, sometimes it move in the positive direction, and sometimes
in the negative. How would a motor behave if, say phase A wires are
OK but phase B connection is bad/broken. Would this cause the motor
to move in the opposite direction to that commanded?

Am more interested in understanding the problem than in getting the
problem solved. Hope someone smarter than me will explain.

Puzzled.



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "forumtvm" <forumtvm@y...>
wrote:

> Hi,
>
> Using DeskWinNC, Camtronics 2A driver, 33VDC power supply, I was
> getting only 16-18 ipm previously.
>
> Happy to report that after changing to a Pentium 4 and DeskCNC

(with

> the same old controller board) I managed to squeeze 35 ipm from the

x-

> axis before stalling. For the z-axis, I could get 17 ipm.
>
> However, the y-axis seem to be acting up. At one stage, I could

only

> get it to make noise without any movement. After powering off,

trying

> another day, it was OK again. Now the y-axis can't seem to make up
> its mind whether to move forward or backward. In MDI
> G91 G01 Y0.1 F10
> it is supposed to move forward (same direction) each time it is
> activated. But what is happening is, sometimes it move forward,

other

> times it move backward.
>
> DeskCNC uses a serial cable from PC to controller board, and

parallel

> cable from controller board to driver. So I try to see if I can
> isolate the problem. I switched to TurboCNC which uses a parallel
> cable direct from PC to driver. Same problem.
>
> What could be the possible cause? Where should I start looking to
> solve the problem?
>
>
> Looks like a lot more work to get a consistent dependable system
> going.
> Thanks
>
> Peter