JackW (Customer) asked a question.
Being new to this I am a little confused as to the differences and necessity of using min & max values of 0 - 65535 vs 0-100%
I have a discharge air temp control loop. Following the video examples, it looks like the 0-65535 is what would be driving my 0-10VDC output on my P3-04DA card which is controlling my heat source (SCR).
That range represents a PID output of 0-100% which I have scaled for display on a C-More HMI. My question is, if I want to have an override at the CMore panel, do I need to create another scale to take a 0-100% from the CMore and convert back to 0-65535? I am correct in assuming that the 0-65535 is the standard range of values representing any given scaling I would use? ie 0-100%, 0-50 GPM, 0-2000 CFM etc?
Is it a matter of resolution as to why we wouldn't simply take our PID output and convert it to 0-100% and then use that in all the downstream logic to drive the analog 0-10VDC output?
Thanks
That card has a 16bit output resolution which is 0-65535 for a 0-10V output. ((2^16) - 1). The D>A converter in the card will take this and create your output.
Inside your ladder, you'd use a scale function to convert your process value from whatever engineering units you prefer to that output range (or your desired range within that range). Make this EU number a float and you'll have decent resolution yet still have a human readable value to manipulate when needed.
Thank you for the answer.
So because I am simply using 0-100% for an output I scaled the "raw" values to 0-100% for the Cmore panel and I created a 0-100% override point and scaled that back to the raw data 0-65535.