Before I order some expensive pressure sensors, I have a trivial question (just to make sure):
The specs read: Excitation voltage 10Vdc,24Vdc(8-36Vdc) Output options: 1.5mV/V, 2mV/V, 2.5 mV/V, 3.33 mV/V,4-20mA,0-10V,0-5V,0-20mA
What does mV/V mean?
Thanks, Mike
Simple :) it is a 4 resistor bridge sensor. If you supply the bridge with 1 volt , it outputs the given number of millivolts for full range signal. So if the bridge allows 10 volt supply, you get 10 times the specified Millivolts.
Ok, you have 1V across the widgit, and you stress the widgit, and it gives you say a reading of 5mV
do the identical with 3v across the widget and it will give you 3 times ie 3/1 the voltage, so15mV
martin
You mean that for the 1.5mV/V option the sensor spits 15 mV at full scale pressure while on a 10V excitation? Isn't that a too noise-prone voltage for full scale?
Mike
Welcome to the world of sensors---15mV is a princely voltage here. The world would beat a path to the door of someone with a clever idea for a stress sensor (or temperature sensor or...) directly giving large voltages.
For example, a typical thermocouple voltage is 3-5 mV/K.
Yep, thats just it, and no, there is no noise problem,its a rather low impedance voltage floating differential output. So you need a differential amplifier for the bridge output. Better buy the sensor with a buildin amp, if they sell it.
Yep, thats just it, and no, there is no noise problem,its a rather low impedance voltage floating differential output. So you need a differential amplifier for the bridge output. Better buy the sensor with a buildin amp, if they sell it.
More like 10-50uV/K for the common types.
it means 1/1000 or 0.001 obviously.
In this instance it means that for an input voltage of X you get an output voltage of Y = X x scale factor in mV/V
Graham
Right.
Not with good signal conditioning and A/D conversion. A load cell can put out 30 mV full scale and weigh things to 0.01% accuracy and linearity.
John
Hello Mike,
That's why we analog guys will always have something to do :-)))
15mV is actually a lot."siliconmike" schreef in bericht news: snipped-for-privacy@m73g2000cwd.googlegroups.com...
15mV is plenty, and it comes from a pretty low impedance. Noise is not a big problem, there are not very high frequencies to be expected in a pressure sensor, so you can filter plenty.15mV is *loads* !
Graham
It IS included, reread the output options, they include 4-20 mA and 0-10 V, this is a fully conditioned sensor.
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