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Thread: CR0032 current input

  1. #1
    Join Date
    Oct 2011
    Posts
    19

    Default CR0032 current input

    I'm running a 4-20 mA current signal into pin 55 of a CR0032 controller. In CONF_IO_CR0032, I have the I00_MODE set to 4 for a current input. When reading the value, I use the INPUT_ANALOG function block on channel 0, mode 7 (which is current input for the function block mode).

    The output of the function block is zero regardless of the input current applied. When I look at the PLC Configuration and check the pin 55 analog input, it ranges from about 600 to 3000, for a 4 mA - 20 mA input range.

    The applied current matches an ammeter in series with the test source and the CR0032 input.

    I'm not sure what's going on here. The value shown at the input doesn't seem to match a mA ur uA current in decimal, hex, or octal number bases. As far as I can tell, the configurations are correct.

    Ideas?

    Thanks.

  2. #2
    Join Date
    Aug 2009
    Location
    ifm Exton, PA
    Posts
    197

    Default

    You do not need to set the IO_MODE of the channel, INPUT_ANALOG block will take care of that.

    The MODE for the INPUT_ANALOG should be set to IN_CURRENT (This is a global constant for the library. The actual value is 4) 7 is not a valid mode value.

    Other mode constants are:
    IN_DIGITAL_H
    IN_DIGITAL_L
    IN_CURRENT
    IN_VOLTAGE10
    IN_VOLTAGE30
    IN_RATIO

  3. #3
    Join Date
    Oct 2011
    Posts
    19

    Default

    Thanks Erik, I'll make the change at the INPUT_ANALOG function block.

    On page 190 of the system manual, current input is shown to be mode 7 for the INPUT_ANALOG function block. If it is mode 4 as you state, then am I missing something in the manual or is there an error in the manual?

    Thanks,
    Dave

  4. #4
    Join Date
    Aug 2009
    Location
    ifm Exton, PA
    Posts
    197

    Default

    It's probably a misprint.

  5. #5
    Join Date
    Oct 2011
    Posts
    19

    Default

    Thanks Erik, the correction to the mode worked--while the value shown in the PLC Configuration screen for the analog input doesn't represent the current, the value read in by the ANALOG_INPUT function block is correct.

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