View Single Post
Old 09-25-2015, 03:39 PM   #2074 (permalink)
Permanent Apprentice
Join Date: Jul 2010
Location: norcal oosae
Posts: 523
Thanks: 351
Thanked 297 Times in 213 Posts
Originally Posted by thingstodo View Post
It is the ground from the 5 pin header. 24V is supplied from the DC/DC converter

DC/DC 24V -------------------------------------encoder +

5 pin A ----------------------10K resistor-------encoder A
                         5K resistor
5 pin gnd ---------------------------------------encoder gnd
                         5K resistor
5 pin B ----------------------10K resistor-------encoder B

15ish volt output of the encoder -> 10K in series with encoder signal 
drops about 10V -> 5K across controller A and gnd give 4.7 - 4.9V signal
did that make any sense?

The aluminum foil was a single wrap around the cat5 cable from encoder to my little circuit board, then from the circuit board to the controller. But, since it is conductive ... it may have touched something that it should not have?
Oh, I may see something here, regarding your shielding.

Generally, you don't want to connect the shield to both the main circuit board's ground and the "satellite" circuit boards ground. The shield should only connect to the main circuit board's ground. Otherwise, you can get current loops that are separate (and dynamic) from the normal ground.

This point was emphasized in my EMI class, as well as the instructions for shielding the inputs on my Sumitomo VFD.

Hope this helps,

  Reply With Quote
The Following User Says Thank You to e*clipse For This Useful Post:
MPaulHolmes (09-25-2015)