[:ol Negative number nightmare!

titoyabril

Member
Join Date
Oct 2007
Location
mount dora
Posts
17
I am seeting up a temperature controller using PID. I have a steam valve and a cooling valve.
I set up the PID output to be Bipolar (-4095 to +4095).
The analog cards are both setup for unipolar 0-4095 input.
i would like to control the cooling valve with a 0 to 4095 signal, and the steam valve with a 0 to -4095 signal (of course i can't use the negative number.)
The output of the PID is in binary, and the analog cards take bcd.
How do i invert the negative binary number, to a positive bcd number.
The question i am proposing is as to how i can control the 2 valves with 1 PID Output.
By the way, i am using a DL260 cpu and directsoft 5
 
I understand that it may sound like a dumb question, because i know that if you multiply a number time -1 it becomes positive. But the software does not seem to allow for that.
 

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