[CAD_CAM_EDM_DRO] Re: Major encoder trouble, need advice.

Hi Randy,

Your $0.02 is as appreciated as anything else!

All measurements have been made at the connector where the signals enters
the drive electronics. I haven't looked at them at the encoder end, partly
because it's hard to access them there.... ;-/

The cable I'm using for the USDigital E7P encoder is 300mm long and is sold
BY USDigital to be used with THIS encoder so I'll be damned if it isn't the
correct one... I initially used this cable which was then extended with my
ordinary cable but when that didn't work I thought I'd use the USDigital
supplied cable until I get THAT working - that's almost four weeks ago :-(

The shield of the encoder cable is now connected at the star-point GND but
was previously connected to GND in the encoder connector on the drive - and
there only. It made no difference moving it.

Thanks!
/Henrik.

-----Original message-----
Henrik:

I see that you have checked the signals with your oscilloscope but you
didn't mention at which points you made the tests. Is there any difference
in what the signals look like at the encoder and what they look like at the
other end where they are input to your controller?

Did U.S. Digital specify twisted pair to be used with their encoders? I
have always used normal shielded cable, not twisted pair. Many of the
encoder manufacturers I have used actually specify twisted pair NOT be used,
these are much higher priced units that U.S. Digital and that may be the
reason.

Another thing to keep in mind is to not attach both ends of the shield,
only connect one end of it to ground or the negative side of the power
line, I didn't see where you said how you had attached the shield.

Now, none of this may help but I thought I would put in my "two cents"
worth.

Randy Abernathy
Industrial woodworking machinery installation, design, repair and servicing
Over 24 year experience with factory training
Fax: 770-974-5295
Phone: 770-974-5295