Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Hi Eric
I was going to put the second s/g on the opposite side to the original one so as to be in compression. The original one is on top so is in extension.I have reduced the gain so as to get only 1v to 1.5v change between rest and full load seems a lot more stable. But will have to change micro to read this change. Had difference between breadboard and circuit board but added cap between + - on the opa.Has been on test for one hour and the output changes by 10mv up then down slowly this is acceptable as i am displaying 0-9 1 volt divided by 10 this is done in the pic which is already working but thats another story .
Regards
bee
Hi Eric
The circuit is working reasonably well as i have built it on a vero board and it all works allthough the opa is working hard with the gain. I will use the second opa as soon as i work out the best configuration.I am not to concerned with temp variations as it is more a comparison between cranks as both at same temp.Very pleased as it gets better everytime i mess around with it.Any ideas on the second opa appreciated.
Regards
bee
Hi
Have found correct pinout in eagle not correct device but same pinout. If IC1A is configured as a differential amp? what would IC2B be configured as a non inverting amp?.Have attached updated working schematic and also how i think the second amp should be configured not sure about values for R1,R7,R8 and by how much to reduce gain of IC1A etc.Thanks
bee
Hi Eric
Still using only one s/g as i got it working reasonably well with one.I still have the 1.5k resistors on the bridge arm with s/g to reduce current is that ok as it seems to still work ok.The caps 100nF/100uF are to stablise supply correct.If you could help with res values would be good, are the values on the drg approximate.Forgive my ignorance but what is AOT on the feedback loop IC1A
Regards
bee