S
Sjouke Burry
- Jan 1, 1970
- 0
Perhaps you need to filter, because when pumping, youGlenn said:I need to maintain pressure on a hydraulic system within a narrow +-3% band
for some tests but the commercial precision pressure switches are way out of
my budget . I have a 4-20ma pressure transducer that I can drive at 24V
with a maximum 700 ohm shunt resistor (Say 680 ohms). I need a switch that
will turn the pump on when the voltage drops below 4.35V and off when it
reaches 4.45V.
I have been experimenting with an LM1458 dual op amp and some 10K trimmer
pots I had on hand and can get a pair of LED's to light as the input voltage
goes high or low outside the .1V range but I am having a brain freeze on how
to latch a relay on when the low op-amp turns on and off when the high
op-amp turns on. I can change the logic by reversing the op-amp inputs but
any way I do it the pump will turn off as soon as the pressure gets in the
range. There will be no deadband so the pump will cycle rapidly.
Any suggestions?
get pressure waves.
Try to look at the sensor output with an osciloscoop,
and check whether you need filtering.