12V encoder interfacing with 7i77, schematic?

Todd Zuercher wrote: What I think you need to do is build a voltage divider with a couple of resisters.
en.wikipedia.org/wiki/Voltage_divider

I'm losing counts on the DRO. Tomorrow I will hook up my scope and have a look at the A and B wave forms simultaneously. My resistors are creating a 4.8V wave. Is that potentially my problem? Should I get it right to 5V?

Any other things I should mess with.

The encoders are not differential. I had no wires hooked to the "negative" side of the encoder inputs (a/,b/) on the 7i77. Any chance I should be hooking my encoder pulses to a/ and b/ vs a and b?

It also seemed like hooking up the index pulse garbled the count more. I'll look at that also.

It's pretty cool that I'm getting data to the DRO.... even though it's wrong

cheers

Got X and Z axes homing to index pulse on encoders and my tool changer working from M6! Huge milestones for me!

Thank you for all the help.

If anyone has any info on my spindle drive and encoder that would be greatly appreciated! Pics of model numbers on first or second post of this thread.























I wanted to backup my files here. Sometimes this computer doesn't see the hard drive ...

cheers all

When 7I77 encoders are in TTL mode, they have a TTL threshold (about 1.7V) so I would make sure the input swings as low as possible, less than .5V if possible. This is complicated by the fact that the inputs have 2K ohm pullups to 5V. This means you may need to lower your divider impedance to get good low level

file backups