I'm using RSLogix 500 and have a MOV instruction with a N13 register, and the source has a constant of 32000. Can you tell me where this 32000 number came from? is it selectable somewhere? I know the programmer is equating it to a 0-30 foot 4-20 analog input signal. I don't want to change this value I just need to understand it's relationship to 0-30 & 4-20.
I'm looking to trigger outputs at different levels below 30 feet.
This number is related to the raw span for any analog value for the PLC Module. It is probably a clamp to prevent the signal to go above 32000. Check your module's raw values (I think the modules numbers span from 6242 to 31,242 for 4 to 20 mA for the SLC family if I remember correctly; you'll need to check your module's manual for the actual values). You change the value to clamp the peak value the register can take.
The triggers you want may be implemented using the LIM instruction, but since your register is raw data, you have to convert your engineering units into raw data to set up the triggers, as many as you wish. Other way to proceed is to use SCP and create a register in engineering units and set up the triggers from there.
I hope this helps.
I looked through he 1746-NI8 manual and a range was shown for Proportional counts (-32,768 to + 32767 range). could this be what's being referenced and how do I verify this is the Data type being used?
Am I thinking this through to much and should I use 16000 as 15 feet as 12 mA and so on or is this careless?
Yes, that raw number count is the one I am referring to. In short, you can clamp the value to a proportional number (say your 16000 for example) as long as the numbers are with the same scaling. This is a way to limit your input values since an analog input can not be forced. If you have further questions, e-mail me at firstname.lastname@example.org and I'll reply to you ASAP.