PID Tuner Forum › Forums › PID Tuner Help › questions on criteria for the input and output
- This topic has 4 replies, 2 voices, and was last updated 1 year, 7 months ago by pidtuner.
October 29, 2021 at 6:06 pm #93
I saw this video with the example of copying data from an ardruino but still wanted to confirm what the output data is that is expected from this program , for example when you do a bump test you turn the equipment on by setting ONE
and the ONE is the output
it appears that alot of data will also work in addition to minimal data from a bump test
and in sumary using a basic temperature analogy of thermostat and thermometer, for best results the input would be the error of the two values, say 77 – 65 = 12 , and need use the controller output of our device as the output column
since the program is modeling the controller and not the system process from that PID system which is the temperature
thanks in advanceOctober 30, 2021 at 8:36 am #94pidtunerKeymaster
It is a common question, and source of confusion. Maybe the following FAQ document can help you clarify the input/output selection:
The program is modeling the system process, not the controller. Try not to get confused by the names of the variables for any specific implementation, what the PIDTuner considers “input” is the input to the process (output of the PID). And what the PIDTuner considers “output” is the output of the process (input to the PID).
Hope the information above makes things a little clearer.November 1, 2021 at 5:42 pm #95
thanks for the pdf it appears to be a recofiguration of the classic block diagram
error_in >> controller >> system >> process
from what I can tell the document is saying to use the actuator value as
the input from 0 to 100 percent……..and either the process or the input error in the PIDtuner column labelled output
this clarifies that the error is not the input but now I am back to clarifying the output column , as to be needing the
since the document kind of goes in circles Im still seeking to clarify if that is the system or the error that will work best for this (in the output column data)November 1, 2021 at 5:45 pm #96
this clarifies that the error is not the input but now I am back to clarifying the output column , (since the document kind of goes in circles) Im still seeking to clarify if that is the process or the error that will work best for this (in the output column data)November 2, 2021 at 10:46 am #101pidtunerKeymaster
The error is the setpoint (SP) minus the process output (PV). The output column must contain the process output.
Every system (process and PID) has an input and an output. That is why it can be confusing. The PID has as input the error (SP-PV), and the control variable (CV) as output. The process has the CV as input and the PV as output.
What the PID tuner need as “input” is the CV and as “output” the PV. Because it is the input and output of the process. Hope this is clearer.
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