plc problem

Discussion in 'General Electronics Chat' started by nomankarachi, Jul 10, 2010.

  1. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
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    hello
    i m workling on a project and using 3 senors in it pressure,flowrate and temperature.
    i hv to interface these sensors to the analog module of plc,the prblem is tht my senior told me tht temperature sensor (pt100) cant be interface with normal analog module for pt100 we need another module.
    kindly help me is this is true ?
    and if it is so any way to avoid module ? i mean can i condition the temperature output by self to make it compatible for normal analog module ???
     
  2. BMorse

    Senior Member

    Sep 26, 2009
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  3. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    I'm assuming your PLC's analog input module is 4-20 ma. You'll need to convert the resistance change of the RTD to the 4-20 your PLC requires. Try here for starters:

    http://www.omega.com/ppt/pptsc.asp?ref=TX86&Nav=temn04

    Root around the Omega site, its pretty good.
     
  4. Jaguarjoe

    Active Member

    Apr 7, 2010
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  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    I don't see that you've specified your PLC or it's analog module, but most that I've worked with have settable input ranges, in voltage or current modes.

    Because your sensor is resistive, you'll need to make it 'active' by adding a voltage reference to it for current mode, or a current reference for voltage mode.
     
  6. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
    0
    thnx to all for rply
    well me using plc of siemens s7200 and analog module of same range 4-20.
    well i got lot of help frm u ppl thn a lot if i ll b in further trouble thn ll ask u guys again
    thnx n bye.
     
  7. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
    0
    hello,
    need help infact advice on 1 more issue.
    i have to use pressure sensor and also the flow rate sensor in my project for the water.
    using plc of siemens s7-200 with analog module em231,
    i m thinking to use the pvc pipe for the flow of water and nearly about 2 or 3 inch. can any 1 sujjest me that which sensors will b easy and goos to use ???
    i think i ve provided all the related info regarding to sensors.
    till now i think for flow this one
    http://www.flow-network.com/calorimetric_flow_switch_kal-d.html
    and for pressure this 1
    http://autonics.thomasnet.com/viewitems/pressure-sensors/pressure-sensors-psa-series-
    kindly tell me r they ll b good or not ? otherwise . . . . . ???
     
  8. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Both of these sensors you linked to have an NPN or PNP open collector output, so if you can utilize those on your PLC then yes they should both work.... but to use them with an analog module when they have a digital output is another thing....

    B. Morse
     
  9. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
    0
    i didnt get ur msg,:confused:
    kindly tell me again plss
     
  10. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    Your first device, Kal-d, only has a setpoint output, so you will not be able to aquire scaled output. I had tossed a couple in the garbage a few weeks back for that very reason.

    The second device indicates a scaled output, but I wouldn't purchase without seeing a full data sheet.
     
  11. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
    0
    oky now i got it :)
    oky then now i ll try to search more sensor for flow so that its output wud be scaled.
    also if u hv any other sensor regarding to it thn plss let me knw.
     
  12. nomankarachi

    Thread Starter New Member

    Jul 10, 2010
    6
    0
    plss tell me about any other flow sensor.
    u know my specs and requirement.
     
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