Adding 1FH Board for Analog Input

    I am working on an application where I would like to be able to set the speed of a specific program step based on an external input (not requiring re-programming or access to the teach pendant).

    I am working with a D series controller.

    The best solution I have been able to come up with is adding a 1FH board to the 1KA board for analog input. Then I can use an analog to digital conversion command in AS language to set the speed of the specific step.

    So...

    1. Any better solutions that I'm not thinking of.

    2. Anyone have experience adding the 1FH board to an existing controller (not factory equipped)?

    3. I have limited experience with AS language, can I set the speed using the analog to digital conversion?

    Thanks!!

    Quote from Lantz

    1. Any better solutions that I'm not thinking of.

    Possibly but all depends on what sort of values you are looking at using.

    - If you are looking at just integer speeds, you could just use some hardwired DI from the PLC O/P.

    - If you are looking at more precise speeds then yes, but you would need to considering filtering.

    - You could just adjust the monitor speed instead of programmed speed as an alternative.

    Quote from Lantz

    2. Anyone have experience adding the 1FH board to an existing controller (not factory equipped)?

    Yep, just a case of installing it on the 1KA and setting the JP and dip switches for the source range.

    You do have a 10V source available on pins 1 and 14 respectively.

    Most systems I know, the PLC or external peripheral use their own source.

    I have attached the analog input manual just in case you haven't got it.

    Quote from Lantz

    3. I have limited experience with AS language, can I set the speed using the analog to digital conversion?

    Never done it, but the result of the A/D conversion result can be defined as a variable.

    That variable can then be used in conjunction with your speed command(s).

    You may want to use some sort of previous speed comparison and only up date the variable if the speed is different than before.

    It all depends on just how you are going to use the A/D result variable:

    - Main program.

    - PC Task (You would use MC SPEED if you are adjusting the monitor speed percentage).

    Quote from kwakisaki

    Never done it, but the result of the A/D conversion result can be defined as a variable.

    That variable can then be used in conjunction with your speed command(s).

    If I am understanding this correctly. I can run the A/D conversion, assign that to a integer variable. Then reference that variable at the specific steps in place of the normal integer value (0-100).

    Quote from Lantz

    If I am understanding this correctly. I can run the A/D conversion, assign that to a integer variable. Then reference that variable at the specific steps in place of the normal integer value (0-100).

    Exactly correct.

    Eg:

    .ch[1] = ADC(1,1); Read Analog value in from channel 1 between 0-10V.

    To get an average, a simple FOR/END can be used as in the manual example:

    Code
    .ch[1] = 0;
.max.samples = 10;
FOR .i = 1 TO .max.samples;
  .ch[1] =  ADC(1,1) + .ch[1];
END;
;
avg.result = .ch[1]/.max.samples;
;

    You could use the CNTADC command instead.......

    Not much to the AS structure of the A/D conversion really.

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