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  • Need some Help with RTD

    HI, im fairy new to the programing game and the boss man throws me a Hot water system that's been partial programed and wants me to add in 2 rtds on the water feed/return line to display temps on a c-more screen.

    im using a DL205 rack and my 2wire signals coming from the rtds are going directly into a Analog input card F2-04AD-1. i could use a bit of help getting started, first of all how should i bring the signals in? should it just be brought in with a IB460 and then Scaled with a IB403? if some could show some mercy on the noob


  • #2
    First thing you need to do is convert the RTD sensor to a 4-20mA signal. The F2-04AD analog input card accepts 4-20mA signals and does to support direct connection to a RTD.

    Second find out what type of RTD you are using. The most common is a Pt100 but check to see what your using.

    Third, find a signal conditioner to support the RTD your using. The signal conditioner will take the RTD as an input and convert it to a 4-20mA signal. You will specify in the signal conditioner setup what temperature equals 4mA and what temperature equals 20mA.

    The 4-20mA output from the signal conditioner will be the input into the F2-04AD.

    From there you can do the programming using the IB blocks you mentioned.

    Here is a signal conditioner that AD sells...

    http://www.automationdirect.com/adc/...itioners/FC-R1

    Comment



    • #3
      Another Thought

      If you're not married to the current analog card, they sell a different analog card made specifically for taking RTD inputs directly, without the need for signal conditioners. You won't need to find cabinet real estate then.

      http://www.automationdirect.com/adc/...I-z-O/F2-04RTD

      This module is set up using jumpers, and when set up and installed, will give you the chosen temp and format in the chosen v-mem location without any scaling being done.

      Just another option,
      Last edited by Bob S BN; 02-18-2010, 02:18 PM. Reason: added direct reading note
      Bob

      Comment



      • #4
        Originally posted by jesawyers View Post
        First thing you need to do is convert the RTD sensor to a 4-20mA signal. The F2-04AD analog input card accepts 4-20mA signals and does to support direct connection to a RTD.

        Second find out what type of RTD you are using. The most common is a Pt100 but check to see what your using.

        Third, find a signal conditioner to support the RTD your using. The signal conditioner will take the RTD as an input and convert it to a 4-20mA signal. You will specify in the signal conditioner setup what temperature equals 4mA and what temperature equals 20mA.

        The 4-20mA output from the signal conditioner will be the input into the F2-04AD.

        From there you can do the programming using the IB blocks you mentioned.

        Here is a signal conditioner that AD sells...

        http://www.automationdirect.com/adc/...itioners/FC-R1
        thanks for the reply, as i have now been informed the rtds are already transmitting a 4-20ma signal so i should be good on that front.

        next question is on the programing side, im having a little trouble understanding the addressing with this system. My AI module is in slot 2 on my 205 rack.
        ch1 - flow transmitter1 (0-900Gpm)
        ch2 - flow transmitter2 (0-900Gpm)
        ch3 - rtd 1 (0-300 *F)
        ch4 - rtd 2 (0-300 *F)
        all channels are 4-20ma. i was planning on bringing the signal in to the plc with an IB-460 and then a IB-403 to scale, and finally directly out to a c-more touchscreen. i cant seem to find much in the ways of examples on this stuff and would just like a bit of advice.

        what i have so far is: for lets say RTD1

        Rung1 - IB-460
        base# - K0
        Slot # - K2
        # of Channels - K4
        Input Data Format - K1
        Input Data Address - V2000

        Rung 2 - IB-403
        Raw - V2000
        High Eng. - k300
        Low Eng. - k0
        Eng(Binary) - V2010

        Rung 3 - Out
        V2010

        is there anything im missing? also will the same method work for the rtds and flow transmitters since they are both just a 4-20 signal?

        Thanks for being patient

        Comment



        • #5
          Your Module set up box will put the raw data for channel 1 in v2000, channel 2 in v2001, channel 3 in v2002, channel 4 in v2003.

          You will then need a seperate scaling I-box for each input channel, 1 for v2000 scaled and put in v2010, 1 for v2001 scaled and put in to lets say v2011, etc...

          Then set tags in your c-more pointed to the appropriate vmem (v2010, v2011 etc..)

          Hope this point you in the right direction,
          Bob

          Comment



          • #6
            ok, now i get that much, so ch3 in through IB-460 on V2002. then scale it with IB-403 Raw#V2002, Eng(binary)V2013?right?

            Thanks

            Comment



            • #7
              This should be what you need. You can copy the section below and paste into notepad and save as a .txt file, and then import into DS5 if you'd like.

              Since you're going to display on a c-more as well, any reason your using binary instead of BCD in your module set up and scaling boxes?


              PLC 250(-1)

              // Rung 1
              // Address 0
              ANLGIN K0 K2 K4 K1 V2000

              // Rung 2
              // Address 38
              STR SP1
              ANSCLB V2000 K900 K0 V2010

              // Rung 3
              // Address 63
              STR SP1
              ANSCLB V2001 K900 K0 V2011

              // Rung 4
              // Address 88
              STR SP1
              ANSCLB V2002 K300 K0 V2012

              // Rung 5
              // Address 113
              STR SP1
              ANSCLB V2003 K300 K0 V2013

              // Rung 6
              // Address 138
              NOP




              Hope this helps make it clear,
              Bob

              Comment



              • #8
                crystal clear this time lol

                Comment



                • #9
                  Originally posted by Bob S BN View Post
                  Since you're going to display on a c-more as well, any reason your using binary instead of BCD in your module set up and scaling boxes?

                  didnt even realize i was doing that. i switched the 403 to a 423.

                  thanks yet again good sir

                  Comment



                  • #10
                    You'll also have to change the data format in your IB-460 from k1 to k0 so it stores the raw data in BCD. Then you'll be all set. C-more can display these with ease. When setting up the tags, be sure to set data type as BCD int 16, and all will be good.

                    Have a good Weekend,
                    Bob

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