I have used the OpenScale in the past with no issues, but I am stumped here. I have checked at the serial out, and I have 5V power coming in. When I check the Excitation Voltage pins they are at @2.5V. Connecting my load cell, the raw pegs to -8388608 immediately and reads nothing. Connected to the load cell, the excitation pins read .5V across them. It is a 0-10V load cell, but this isn’t making sense.
If the load cell output is 0-10 volts, it already has an amplifier built in. These exist but aren’t too common.
Can you please post the details about your load cell? We can’t count on wire colors from one mfg to the next and some even have extra wires for temperature compensation and TEDS and stuff.
I think the “Electronics Guru” who told me it was 0-10V was wrong. I am seeing 3mV/V and no other rating. I think his point was rather that we should be applying 10 volts of excitation for an accurate reading, which I don’t disagree with.
https://tacunasystems.com/products/load-cells/s-type/amcells-stl-series-s-type-s-beam-alloy-steel-load-cell/ The wiring is standard and also how I had it rigged up. Any thoughts on why the input voltage is chopped to 2.5 V from the input on the openScale
Thanks for the link. The wire color pinout looks ordinary.
The next most likely is that there’s a short somewhere. If we’re really lucky, one of the wires has a nick to cable shield or something easy to spot. You can eliminate the OpenScale by just connecting a 5-15 VDC power supply to the red & black excitation wires. The output should be pretty close to 0 millivolts but get larger when loaded. Of course, the signal will rise a LOT less for a given load if it’s the 40,000 version of the load cell vs the 100 pounder. Also, it’s unclear whether tension or compression is positive polarity so it may drive backwards from what you’re expecting.