Fine Tuning V2 - Siemens SIMATIC S7-1200 Function Manual
Pid control
Hide thumbs
Also See for SIMATIC S7-1200:
- Manual (364 pages) ,
- System manual (338 pages) ,
- Reference manual (89 pages)
Table of Contents
Advertisement
5.2.2.2
Fine tuning V2
Fine tuning generates a constant, limited oscillation of the process value. The PID
parameters are tuned for the operating point from the amplitude and frequency of this
oscillation. All PID parameters are recalculated from the results. PID parameters from fine
tuning usually have better master control and disturbance characteristics than PID
parameters from pretuning. You obtain the best PID parameters when you perform pretuning
and fine tuning.
PID_3Step automatically attempts to generate an oscillation greater than the noise of the
process value. Fine tuning is only minimally influenced by the stability of the process value.
The PID parameters are backed up before being recalculated.
The setpoint is frozen during fine tuning.
Requirement
● The PID_3Step instruction is called in a cyclic interrupt OB.
● ManualEnable = FALSE
● Reset = FALSE
● The motor transition time has been configured or measured.
● The setpoint and the process value lie within the configured limits (see "Process value
settings" configuration).
● The control loop has stabilized at the operating point. The operating point is reached
when the process value corresponds to the setpoint.
● No disturbances are expected.
● PID_3Step is in inactive mode, automatic mode or manual mode.
Process depends on initial situation
Fine tuning proceeds as follows when started from:
● Automatic mode
Start fine tuning from automatic mode if you wish to improve the existing PID parameters
through tuning.
PID_3Step controls the system using the existing PID parameters until the control loop
has stabilized and the requirements for fine tuning have been met. Only then will fine
tuning start.
● Inactive or manual mode
Pretuning is always started first. The determined PID parameters will be used for control
until the control loop has stabilized and the requirements for fine tuning have been met.
Only then will fine tuning start.
PID control
Function Manual, 03/2017, A5E35300227-AC
Using PID_3Step
5.2 PID_3Step V2
131
Advertisement
Table of Contents
