Allen bradley PLC Analog Input

Hi All,

I got one program from my customer.Pls check the attachment picture.

The formula is used to convert 4-20 mA to flow rate (Liter per minutes.)

I can see the calculation result on HMI as a flow rate.

I think, something wrong with the formula because the reading on the HMI is not actual flow rate.I can see the actual flow on flow meter.

Can anyone suggest me which formula should i use to get the actual flow rate reading?

Thank in advanced.

I can't really see your calculations, but they look mostly wrong. Why are you trying to normalize with 65534? And if you do, you should make the formula explicitly calculate in floats by making all of your constants xxxxx.0 (65534.0).

Why can nobody look up scaling? This is simple, basic, low-level math. Why must it be such a mystery and be re-invented (incorrectly) 4 million times a day?

/shrug.

If you are going to normalize, then operate all in floats. Divide your raw input value by the maximum to get a range of 0 to 1, then multiply that by your maximum engineering units.

Or why not take the easy option and download the SCP AOI from Rockwell.

http://samplecode.rockwellautomatio...uments/webassets/sc_legal_info.hcst?dID=62087

My 2p worth

Mark