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CCS/PGA900EVM: how Test 4-20mA mode of PGA900EVM board?

JUAN ARAUJO
Prodigy 140 points

Part Number: PGA900EVM

Tool/software: Code Composer Studio

Hello, I want to check the two-wire current loop mode, 4-20mA, I have the PGA900EVM board connected to the PGA900 GUI application with the USB2ANY, in the software I put RLOOP 10ohm. put the jumpers in current mode, and connect the jumper (J1, J2, J3) to test the 4-20mA loop, but the current loop I get is greater than 150mA.
For the PGA900 GUI software to communicate correctly with the PGA900EVM board, must the board be powered with 24V (J20-J21)? Does the PGA900 that comes with the board already have a firmware recorded? Is it ready to be used with the PGA900 GUI software?

  • 0
    TI__Mastermind 31655 points

    Hello Juan,

    Yes, you can test the 4-20mA output of the PGA900 using the EVM, but without firmware programmed you will only be able to do this in the digital interface mode. You will have to manually set DAC codes in the DAC and PWM settings menu (don't forget to enable the DAC and the TEST_MUX_DAC_EN at the top of the DAC configuration) and to configure the Current amp. 

    Please double check your jumpers against the DAC Output Configurations section of the schematic in the EVM user's guide. The best way to measure the current in the loop is to place your ammeter in series across J10.

    The PGA900 that comes with the EVM does not have any firmware loaded. Because of this, the input will not be tied in any way to the output. You will have to program your own firmware to do this. Firmware support for the PGA900 is limited (https://e2e.ti.com/support/sensors/f/1023/t/802433). I recommend looking into the PGA300 or the PGA305 instead to reduce development time, since they have integrated compensation and do not need firmware to be developed. The EVM is the same, so you can order PGA300 or PGA305 samples and use them directly with your PGA900EVM.

    Regards,