Adjusting Infinity IRS servo controller

I got a request from @bobterry99 about adjusting Infinity servo controllers. Inside the controller are 4 pots:

Left side level (amplitude)

Left side DC offset

Right side level (amplitude)

Right side DC offset

See the attached photo. I used a 2 ch oscilloscope to monitor the input and output while adjusting. With 4 ch, you could monitor both channels...

jtucker10-31-2023 9:35pm

jtucker OP Details Discussions Posts This discussion Message User 79 posts 10-31-2023 at 09:35pm Copy Comment URL Report Comment Edit Delete For some reason the picture did not post. Anyone know how?
erik_squires Details Discussions Posts This discussion Message User 16,327 posts 11-01-2023 at 12:12am Copy Comment URL Report Comment Edit Delete DC offset is adjusted for minimum DC on the output. The level trim adjustments are just that. Apply a similar signal to each input and adjust so that the outputs are equal.
bobterry99 Details Discussions Posts This discussion Message User 3 posts 11-02-2023 at 08:14pm Copy Comment URL Report Comment Edit Delete Thanks for that picture, jtucker. Is it possible there is an error? Referencing the ECU schematic seen here, it seems to me that you show adjusting potentiometer R30 for the level. But that seems like the wrong one to me. I think the correct one is R23, since it is controlling the amount of negative feedback of the amplifier comprised of ICa, ICb, and ICc. Potentiometer R30 sets the level of the output from the amplification of the accelerometer signal. I’m going to see what some of my electrical engineering buddies think.