Mesa 7I73 and Grayhill Optical Encoders - 4.7K or 10K Pullup Resistors?

Merry Xmas guys,

I'm currently running a Mesa 5i25/7i76 setup on a small CNC lathe, and plan to fit a Mesa 7I73 for the control panel. I will be using a typical 100PPR hand pulse encoder and axis select/increment switches for manual movement of the X and Z axis. No problems there, as I've done the same on a CNC router before. I would also like to fit two Grayhill rotary optical encoders for manual override of the spindle speed and axis feed, and connect them to ENC1 and ENC2 on the P2 connector.

Where I'm coming unstuck is a difference between the stated value of the pullup resistors fitted to the Mesa card, and what Grayhill has specified for their 62SG series optical encoders. The Mesa card has 4.7K resistors as part of the board, and Grayhill notes the requirement for 10K resistors on the specification sheet, (see below snip). Is this critical, or can I ignore it without damaging the opto/electronic doovies inside the encoders. Any advice or comment would be appreciated.

Cheers, Steve.

The 4.7K pullups wont hurt the encoder, the only possible issue is that the low level A,B outputs will be too high. You can check this with a voltmeter when A and B are low

Thanks for the advice,

As you suggested, I hooked the encoder to a benchtop power supply, and tested it with a multimeter using 10K and 4.7K resisters. In both cases, the low value was less than 0.4v, and the high value was greater than 4.7v.

I have just connected the encoder to the ENC1 input on the 7I73 card as a feed override control, and it works fine.

Cheers, Steve.