: : : ok.. i have a pressure sensor connected to a hydraulic system. What i want to do is to receive the pressure sensed by the sensor to a computer and get that data and plot a graph of pressure vs time.
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: : : Now what is the device i need which will convert the pressure sensor signals to a format which can be read by a computer? I would like to know all the hardware details i will be requiring and how to configure it.Which port do i need to use.
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: : : Once i can get the value in my computer then the rest can be done in VB.
: : : I am sound in Visual Basic but have no idea in this feild. So please help.
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: : : Any help would be highly appreciated.
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: : More specs on the sensor would help. Is it calibrated already, or do you have to do that? is it a voltage or current output, or digital? Is it actually an output, or does it just vary the resistance, requiring you to put a voltage source in series, and an opamp to convert the current to voltage?
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: Well the sensor is not callibrated. I'd also like to know that how can I callibrate it. It simply generates a current proportional to the pressure sensed by it in the system. i.e the input is analog not digital.Yes it does give an output of some mA of current.
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: Any further help will be appreciated.
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Do you have to put some voltage on one end, and a current comes out the other? if so, set up an opamp with a feedback resistor, probably a potentiometer so you can calibrate it, from the output to the inverting input, and tie the other input to ground. Put the output from the sensor to the inverting input, and, at maximum pressure, set the potentiometer to some value, probably the max of your adc (which I will talk about later). then, at minimum pressure, (I'm assuming here that this works, if not, set voltage for minimum pressure and this step for maximum pressure), make note of the output voltage. If it's significant, apply some voltage to the noninverting terminal of the opamp, probably from the wiper of a potentiometer, and see if you can get it to be about 0. Take this output to an analog to digital converter, with no more bits than the number of input data pins you have. You'll probably need one output pin to tell the adc when to sample, and one extra input to tell you when it's done. They usually aren't that slow, so it may not be a problem. as for calibrating it, there are two methods. I'd recommend you shift and scale the output in your program, so you get as much precision as you can get from the sensor.