7.10.3 Rate Limiter
Downstream of the control variable limiter there is another limitation which limits the
changes to the control variable per sampling segment. By P 2680[0] - CON_PRC_
Rate Limiter the limitation of the control variable steepness per millisecond can be
parameterized. By way of index (0) the limitation is active in standard process
controller operation. By way of index (1) reduction of the I-component is activated
(see table). With P 2672[0] - CON_PRC_OUTSEL = 3 the process controller delivers
an additive position reference value. The rate limiter limits the possible control
variable change. The control variable change each time interval by the process
controller results in a speed change on the motor shaft.
Example
The amount of the process controller to change the speed on the motor shaft should
not be higher than 100 revolutions per minute. To achieve this, the value of
parameter P 2680[0] - CON_PRC_RateLimiter must be parameterized with a value
corresponding to the user unit. The unit of this parameter is [x/ms]. The x stands for
the respective unit of the process controller output variable. In this example the
control variable (additive position reference) has the unit "Increments" (see also
P 270[0] - MPRO_FG_PosNorm). This parameter indicates how many increments
correspond to one motor revolution.
Conversion from [rpm] to [Inc/ms]
n
change
= 100 rpm
P 270[0] - MPRO_FG_PosNorm in Inc/rev
Internal position resolution = 1048576 inc/rev (default)
ID No.: 0842.26B.5-01 Date: 09.2020
ServoOne - Device Help
174
7 Control
To reduce the I-component, the same method is applicable P 2680[1] - CON_PRC_
Rate Limiter [Inc/ms]).
P 2680[0] - CON_PRC_Rate Limiter = n
change
*1048576 *1/60000
P 2680[0] [Inc/ms] = 100 [rpm] * P 270[0] [Inc/rev] * 1/60 [min/s*] * 1/1000 [s/ms]
7.10.4 Parameters
ID
Index Name
Unit
Description
2659
0
CON_PRC_Kp
Process controller: gain
2660
0
CON_PRC_KP_SCALE
%
Process controller: gain scaling
2661
0
CON_PRC_Tn
ms
Process controller: integral action time
2662
0
CON_PRC_
REFOFFSET
Offset of the technological controller output
2663
0
CON_PRC_LIMPOS
Positive limitation of the actuator variables
2664
0
CON_PRC_LIMNEG
Negative limitation of the actuator variables
2665
0
CON_PRC_CDIFF_
SIGN
Process controller: sign modification
2666
0
CON_PRC_REFVAL
Process controller: setpoint
2667
0
CON_PRC_REFSCALE
Scaling factor for setpoint
2668
0
CON_PRC_ACTSEL
Process controller: selection of the actual value
2669
0
CON_PRC_
ACTOFFSET
Input calibration: offset
2670
0
CON_PRC_ACTTF
ms
Process controller: Time constant for filtering
the current actual value
2671
0
CON_PRC_ACTSCALE
Scaling of the filtered input signal
2672
0
CON_PRC_OUTSEL
Process controller: Selection of the output
variable
2673
0
CON_PRC_RAW_
ACTVAL
Actual value of the input signal
2674
0
CON_PRC_ACTVAL
Input signal after scaling and filtering
2675
0
CON_PRC_CDIFF
Process controller: control deviation
2676
0
CON_PRC_OUTVAL
Process controller: output value
Table 7.48: “Process controller” parameters
