Shop OBEX P1 Docs P2 Docs Learn Events
100PSI Transducer Code — Parallax Forums

100PSI Transducer Code

anaxcontrolanaxcontrol Posts: 23
in BASIC Stamp
I'm looking for some code for Basic Stamp 2 (2PX24) for 3 wire 100PSI pressure transducer. Anyone have some guidance?

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    You didn't include much info to go on. Do you have a data sheet for the transducer that you can post?

    -Phil
  • anaxcontrolanaxcontrol Posts: 23
    You're right, I did not give much info. Attached is all I have (ebay special). Hopefully this clarifies a bit. Thanks for the fast reply.

    pdf
    pdf
    100PSIPressure.pdf
    127K
  • stamptrolstamptrol Posts: 1,731

    For easiest use, you'll need an a/d converter. 12-bit a/d are quite common and the LTC1298 is a good , 8-pin unit that will give you 2 selectable channels.

    Parallax used to sell the chip and there is sample code available.

    Cheers
  • Alexander (Sandy) HapgoodAlexander (Sandy) Hapgood Posts: 360
    anaxcontrol wrote: »
    You're right, I did not give much info. Attached is all I have (ebay special). Hopefully this clarifies a bit. Thanks for the fast reply.
    That graph looks similar to the one for some pressure transducers I'm using though mine are rated to 3,000 PSI and the code I wrote to read the transducers is all PASM. Is there a label on the transducer giving a part number, model number, or manufacturer name?
  • kwinnkwinn Posts: 8,697
    Since the output is an analog voltage you will need to convert that to a number. That can be done using an ADC chip, two propeller pins as a sigma/delta ADC, or a V-F chip.

    If you go the ADC route an 8 bits is fine since the transducer accuracy is only 1.5%, although a higher resolution (10, 12, or more bits) would also work. Best to select one that has a driver in the OBEX.

    For a V-F chip you can use a single pin to measure the frequency.

    Once you have a voltage value converting it to pressure is simple.
  • Alexander (Sandy) HapgoodAlexander (Sandy) Hapgood Posts: 360
    Providing the transducer reading directly to an ADC might not work very well in all cases. I needed to use an amplifier between the sensor and the ADC to get good results for my application. You're looking for something called an 'instrumentation amplifier' but I can't remember the exact part number or the manufacturer. The one that I used was advertised as being unity gain stable and has proven to be so.
Sign In or Register to comment.