Reason to scale 0-20mA flow meter this way?

[Stefan009]

Hi, im currently re-doing a previous employees code, and cannot ask him specifically.

The flow meter sents 4-20mA depending on 0-120 litres per minute the sensor say.
In the omron code he first scales the mA value with 0-8000 (X0 = 0, X1 = 8000).
Then he takes this output and scales the 0-20mA to 0-PreviousScaleValue on X0-X1.

Any ideas why he used 8000 and not just the 4-20mA / 0-120 lpm?

 

 

[IO_Rack]

Most likely this is the resolution of the analog input card. 8000 digital units for full scale. The resolution can be found in the data sheets or Toolbox in Sysmac Studio.

[photovoltaic]

The card resolution is 0-8000, many people like to also scale 4-20ma so that when you're commissioning you can send the PLC 8ma for example and see the actual ma value in your code instead of trying to scale it in your head.

[Stefan009]

Ah ok. The few Analog cards i have worked with previously only outputed the actual mA value, i did check around the settings for this card but didnt see any reference for the 8000 in there that could give a clue.

Then the code makes sense now that i know the card outputs 0-8000 from the 4-20mA input.

[Crossbow]

What brands have you used?  I have never seen an analog card that put out actual value.  Everything I have worked with puts out an integer numeric value indicating the range, like 0-1000, 0-4000, 0-8000, 0-32000, etc.