TimD
Lifetime Supporting Member
Hi, I have a vacuum transmitter, it's range is 30 to 0 inches of mercury. My spec calls for inches of water, no problem, use SCP to scale 0-16733 to 0-408 and done.
Now the tricky part, the transmitter outputs ~20ma at 'rest' ie. no vacuum.
SO I have a PID loop which works backwards, is there a way to reverse my numbers so that my operator can enter a meaningful setopint and read meaningful transmitter output while looped?
I can't set my scaling block in reverse
I also can't rewire or add a signal conditioner. This must be done in software (and tonight!)
Thanks all. Best PLC forum ever.
Tim
Now the tricky part, the transmitter outputs ~20ma at 'rest' ie. no vacuum.
SO I have a PID loop which works backwards, is there a way to reverse my numbers so that my operator can enter a meaningful setopint and read meaningful transmitter output while looped?
I can't set my scaling block in reverse
I also can't rewire or add a signal conditioner. This must be done in software (and tonight!)
Thanks all. Best PLC forum ever.
Tim