Specifications
Chapter 3 - AsconControlLib
105
3-3-9 S2_EZ_TUNE
FB Prototype
S2_EZ_TUNE
Input parameters
Output parameters
Description
This function block is able to perform a tuning calculation using the “
Step
Response
” method with a
ATB
parameter. The
ATB
value affects the quality of the
results of the method: higher is its value, better are the results, but heavier is the
perturbance caused to the control process; the solution is to choose a correct
compromise. At the moment of the run command of the tune process, if
MEAS
is
close to
SP
, the controller forces the output to the lower limit value in order to
increase the error (SP - MEAS) to the value specified by ATB. Before running this
procedure, please verify that the modified caused error can be reached by the
process (e.g.: in an ambient temperature process with only heat control, the tune
setpoint value
SP
-
ATB
is quite impossible to be reached).
Input Type Description
ENABLE BOOL Function block enable
SP REAL Setpoint value [0…100.0]
MEAS REAL Measure value [0…100.0]
ACT_TYPE BOOL P.I.D. action type
ATB REAL Threshold value [0....100.0]
OUTLO REAL Lo value for OUT output [0…100.0]
OUTHI REAL Hi value for OUT output [0…100.0]
Output Type Description
TOUT REAL Function block output [OUTLO…OUTHI]
TPB REAL Calculated proportional band [%]
TTI REAL Calculated integral time [s]
TTD REAL Calculated derivative time [s]
TBMP BOOL Bumpless command for the P.I.D.
TRUNNING BOOL Running flag
TVALID BOOL Successful tuning calculation flag
ENABLE
SP
MEAS
ACT_TYPE
ATB
OUTLO
OUTHI
BOOL
REAL
REAL
BOOL
REAL
REAL
REAL
¡
¡
¡
¡
¡
¡
¡
REAL
REAL
REAL
REAL
BOOL
BOOL
BOOL
TOUT
TPB
TTI
TTD
TDBMP
TRUNNING
TVALID
¡
¡
¡
¡
¡
¡
¡
STEP response Autotuning procedure
when PV > (SP - ATB)
ATB
SP
SP
PV variable
Control output
Control output
End of tuning operation
and setting the new
calculated terms
End of tuning operation
and setting the new
calculated terms
Start of autotune operation
Start of autotune operation
Autotuning
SetPoint
SP - ATB
STEP response Autotuning procedure
when PV < (SP - ATB)
PV variable
Setpoint change
Setpoint change