The Cranky Sysadmin A world of technology, fun, and ignorant rants.

February 18, 2013

HP HEDS-7501 encoder data

Filed under: Arduino,Electronics — Cranky Sysadmin @ 4:44 pm

I recently tore down some old controller for an X-ray device that I bought at a surplus shop for $15. I couldn’t find a data sheet for this model, so I derived the pinout from the circuit it was in. The pinout and characteristics that I could figure out follow the fold.

This is an HP rotary encoder with two apparent channels, A and B. It seems to produce pretty standard quadrature encoding. The pinout is:

1) channel b
2) +5v (I supplied voltage here)
3) gnd
4) gnd
5) gnd
6) gnd (use this if you connect no other grounds)
7) ?
8) channel a
9) +5v
10) ?

I can’t get the encoder to work at 3.3v. This is an old encoder, so I’m not surprised. The encoder seems to produce about 256 (+/- 20) pulses per full rotation or 512 changes in channel a. I used one of the example sketches at the arduino playground to test the encoder.

I’ll be using it to build a signal generator once my cheap dds modules from china show up. Stay tuned for that project.

No Comments »

No comments yet.

RSS feed for comments on this post.

Leave a comment

Powered by WordPress