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Monitor Amperage with a Stamp — Parallax Forums

Monitor Amperage with a Stamp

Aaron WallAaron Wall Posts: 31
edited 2009-02-16 03:19 in BASIC Stamp
I want to monitor the amperage flow of a circuit with a basic stamp. As much as several amps, any ideas?
I was thinking of using an amp clamp, those output simple signals that a DVOM can read.
But something less expensive would be nice, I have four circuits to monitor.

Comments

  • Carl HayesCarl Hayes Posts: 841
    edited 2009-02-15 05:46
    It's difficult to make sensible suggestions without more information.

    How much accuracy do you need?

    How much resolution do you need?

    How much precision do you need? Note: these three questions are not the same. Accuracy, precision, and resolution are distinct, not the same thing.

    What electrical and magnetic noise is likely to be present?

    AC or DC? If AC, what frequency? If DC, do you need to measure currents flowing in both directions, or only one?

    How much voltage drop can you stand in the sensor?

    Do you need to isolate the sensing equipment from the conductor that is carrying the current that you want to measure, or can it be in electrical contact with it??

    How often do you need to measure the current?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    · -- Carl, nn5i@arrl.net
  • technoobtechnoob Posts: 21
    edited 2009-02-15 07:05
    Sam boat as Aaron,

    I need to monitor DC current into or through·an 800 watt electric motor ruinning between 800 and 2000 rpm.··Amperage values·will vary from minimal load of 7 or 8 amps to peaks of 40 amps· I would like·resolution to be in .25 amp increments if possible.·· And Accuracy needs to be in 10ths.·· It is 48 volt system.· The motor and the sensors along with a BS2p40 are on the same DC supply.· I will be filtering the logic / sensing power so noise in the circuit will be minimal.·· EM will be a little high due to proximity to the Motor.·

    I cant sheild the motor due to heating issues.·



    Im a total noob on this stuff Carl so any advice you can give would be much appreciated.·· My goal with the current sensor is to convert it to an lcd display and transmit the data via rs232 for analyis in excell.

    thanks



    BTW· Im diggin through this web site to learn about this stuff

    http://scienceshareware.com/how-to-measure-AC-DC-current-with-a-hall-effect-clamp-.htm
  • technoobtechnoob Posts: 21
    edited 2009-02-15 07:35
    Here·is another·option for sensing current with small sensors...

    The company is GMW and associates

    Here is the web site.· http://www.gmw.com/magnetic_sensors/sentron/csa/CSA-1_Acc.html· Its an 8 pin IC.·· Check out the data sheet on the CSA-1V

    I like the little "R/D Kits" they have.····A little more expensive but immeidatly installable.



    Im going to check and see if Dallas Semiconductor (Now Maxxim IC) has a "One wire" current sensor.


    L8r
  • Aaron WallAaron Wall Posts: 31
    edited 2009-02-15 14:35
    Thanks Technoob, I'll look into those when I get home from work today.

    For my application, I want to monitor a power window motor in a car. The amperage spikes when mechanical resistance is applied to the assembly. This is the same system the auto up features on new cars use to detect when something is in the path of the window on it's way up, such as a hand, knee or tongue. You know, anything you don't want rolled up in a window.

    I haven't pulled the door apart yet to get exact specs. I need to buy an amp clamp for my DVOM any way, then I can get my range of normal operation amperage vs spike amperage.
  • Carl HayesCarl Hayes Posts: 841
    edited 2009-02-15 14:52
    Well, you don't need to disassemble the door. The current that operates the window motor flows through other wires in the car, some of which are easy to get to.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    · -- Carl, nn5i@arrl.net
  • davejamesdavejames Posts: 4,047
    edited 2009-02-16 03:19
    You may be interested in one of these...

    DJ

    http://forums.parallax.com/forums/default.aspx?f=15&m=327234
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