4 Replies Latest reply on Feb 23, 2015 6:59 AM by user_14586677

    current Measurement

    yonkou.claire

      Hello everyone,

         

      how can the current measurement be done with PSOC 5? Under paragaph 8.12.2 First Order Modulator-SC Mode, there is written, that applications such as current measurement can be done.

         

      In the case, which it is possible, what is the theoretical sensitivity? I would like to measure current arround 20A (the voltage is 800mV)

         

      Thanks for your help

         

      Regards

         

      Rosine

        • 1. Re: current Measurement
          user_14586677

          Questions -

             

           

             

          1) Hi or low side measurement ?

             

          2) The 800 mV comes from what, is it directly proportional to current

             

          in device ?

             

          3) Accuracy and resolution of measurement needed.

             

          4) DC or AC measurement ?

             

          5) What doc is this in "Under paragaph 8.12.2 First Order Modulator-SC Mode,"

             

           

             

          Regards, Dana.

          • 2. Re: current Measurement
            user_342122993

            @Rosine,

               

            First, you need some transducer Current -> Voltage, like this one

               

            http://www.ebay.com/itm/New-design-20A-range-Current-Sensor-Module-ACS712-Module-Arduino-module-ACS712T-/181026550196?pt=LH_DefaultDomain_0&hash=item2a2605f1b4

               

             

               

            Second you will need to measure Transducer's Voltage outout using PSoC5LP DelSigADC (see PSoC examples).

               

            odissey1

            • 3. Re: current Measurement
              yonkou.claire

              Hello Dana, odissey1,

                 

              1) Hi or low side measurement ?

                 

              what is Hi or low side measurement, please can you be more precise?

                 

               

                 

              2) The 800 mV comes from what, is it directly proportional to current in device ?

                 

              The 800 mV is the voltage output of the current sensor. I think that  PSoC5LP DelSigADC can measure this voltage level as suggested by odissey1.

                 

               

                 

              3) Accuracy and resolution of measurement needed.

                 

              I don´t understand very well

                 

              4) DC or AC measurement ?

                 

              The HLSR-P serie current sensor deliver a DC Voltage

                 

              5) What doc is this in "Under paragaph 8.12.2 First Order Modulator-SC Mode,"

                 

              It is CY8C58LP_001-84932_OG_V

                 

               Thanks for replying and the suggestions

                 

              Regards

                 

              Rosine

              • 4. Re: current Measurement
                user_14586677

                What is Hi or low side measurement, please can you be more precise?

                   


                   

                Hi side measurement means you place the current sense R in the hot side of

                   

                the power to the part, in this case PSOC Vdd. Low side would be in the Vss

                   

                lead of PSOC.

                   

                 

                   

                 

                   

                3) Accuracy and resolution of measurement needed.

                   

                 

                   

                Accuracy is how close to the actual value do you want to read the current. So if

                   

                current is 1 A do you wish to measure 1A +/- 10% or +/- 5% or.....

                   

                Resolution is when you digitize a value each bit of A/D represents the minimum

                   

                detectable current value. So say you use A/D at 10 bits, its full scale range is

                   

                1.024 V, then its resolution is 1.024 V / 1024 = ~ 1 mV

                   

                 

                   

                5) What doc is this in "Under paragaph 8.12.2 First Order Modulator-SC Mode,"

                   

                It is CY8C58LP_001-84932_OG_V

                   

                 

                   

                 

                   

                I am still not clear on what document you are lookimng at, datasheet for part, ap note,

                   

                TRM......