hello,
I have an application. It is a loadcell conditioning circuit. I use an A/D converter module which accepts signal +/-10V range. Therefore I need to amplify my loadcell signal to +/-10V range.
I have +/-15V source present from power supply. Right now first I use voltage regulator LM337 in order to filter power supply. Since this board is used in industrial machine always there are a lot of noise sources present. I also use ref102 in order to have very stable voltage source for loadcell. I use the following schematic
I use this voltage to excite my loadcell. Output of the loadcell is fed into AD620 ins. amp. and using the circuit below.
I remove the dead-weight from my loadcell.
It is basically a POT. I adjust my POT so that output of the AD620 is near 0 V because in filtering circuit I further amplify my signal.
My problem is that I need to adjust this digitally. Probably with a D/A converter. Since generally all converters require 5V. Than I need to add one more regulator. This regulator must be very precise I guess. So I think of using REF5050 with a circuit like below.
But it did not worked. As far as I know in order to increase current this must be a valid circuit.
I need an advise on this circuit. How can create regulated voltage sources to my loadcell and amplifiers, and also to D/A converter.
Can anyone think of a wiser solution?
I have 5V on a different circuit near this circuit but that circuit has motor control IC's which can introduce noise to this circuit. So I am not planning to use that 5V. Normally they are isolated. and I am planning to use opto-couplers to control D/A converter.
Thanks,
DC