7.10.2.4 PI process controller
Deviation P 2675[0] - CON_PRC_CDIFF will be the difference between the scaled
process controller setpoint and the scaled and filtered actual value. The sign for this
deviation can be inverted with P 2665[0] - CON_PRC_CDIFF_SIGN (CON_PRC_
CDIFF_SIGN = -1).
This deviation will be passed on to the process controller. This controller is
implemented as a PI controller with output limiting and an anti-windup function.
Users can set a Kp gain with P 2659[0] - CON_PRC_KP, Kp scaling with P 2660[0] -
CON_PRC_KPSCALE and a reset time with P 2661[0] - CON_PRC_TN. If the
integral-action time is set to the maximum parameter value, the I-component of the
controller is inactive. (CON_PRC_TN = 10000 [ms]).
Moreover, an offset can be added to the signal at the controller’s output by using
P 2662[0] - CON_PRC_REFOFFSET. After this, the totalled manipulated variable
will be passed through a limiter. The user can parameterize the limitation via
parameter P 2663[0] - CON_PRC_LIMPOS for the positive limit and P 2664[0] -
CON_PRC_LIMNEG for the negative limit.
Downstream of the control variable limiter there is another limitation which limits the
changes to the control variable per sampling segment. By way of field parameter
P 2680 - CON_PRC_RateLimiter the limitation of the control variable steepness per
millisecond can be parameterized. Subindex 0 is for the limiting used for standard
process controller operation and subindex 1 is for reducing the process controller’s
integral term. For more details on how to set the rate limiting, see Section "Rate
7.10.2.5 Manipulated variable
The process controller’s manipulated variable downstream of the rate limiter (P 2676
[0] - CON_PRC_OUTVAL) can be mapped to various internal drive setpoint or feed-
forward control values. The selection is made via P 2672[0] - CON_PRC_OUTSEL.
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
171
7 Control
Setting
Name
Description
0
OFF
No intervention point
1
REFTORQUE
Additive torque reference
2
REFVEL
Additive speed reference value
3
REFPOS
Additive position reference
4
MPPRO
Reference value for MotionProfile via
P 2678[0] - CON_OUTSEL_MOPRO
5
REFVEL_RAMP
Additive speed setpoint on ramp
Table 7.47: Selector for mapping manipulated variable P 2676[0]
When selecting the additive setpoints (1-3 and 5), it is important to make sure that
they are connected to the respective position in the control structure using internal
units (see "Image 7.46: Schematic of process controller").
The conversion details for converting internal units to user-specific units must be
gathered from the configured user units. These user units can be found under
“Motion Profile --> Standardization/Units” in the operating tool. It may be possible to
track the conversion between user units and user-specific units depending on
whether the user units have been set up as per CiA 402, SERCOS, or with a user-
specific format. P 283[0] - MPRO_FG_Type can be used to view which setup
method was used.
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
