Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 667)

L-force | PLC Designer
PLC Designer Libraries
DMS 3.2 EN 02/2011 TD29 665
19.2.4 Controllers
PD
The library util.lib provides the following PD controller function block:
Inputs of the function block:
Variable Data type Description
ACTUAL REAL Current value of the controlled variable
SET_POINT REAL Desired value, command variable
KP REAL Proportionality coefficient, unity gain of the P-part
TV REAL Derivative action time, unity gain of the D-part in seconds, e.g. "0.5" for
500 msec
Y_MANUAL REAL Defines output value Y in case of MANUAL = TRUE
Y_OFFSET REAL Offset for the manipulated variable Y
Y_MIN, Y_MAX REAL Lower resp. upper limit for the manipulated variable Y. If Y exceeds
these limits, output LIMITS_ACTIVE will be set to TRUE and Y will be
kept within the prescribed range. This control will only work if
Y_MIN
MANUAL BOOL If TRUE, manual operation will be active, i.e. the manipulated value will
be defined by Y_MANUAL.
RESET BOOL TRUE resets the controller; during reinitialization Y = Y_OFFSET.
Outputs of the function block:
Variable Data type Description
Y REAL Manipulated value, calculated by the function block (see below)
LIMITS_ACTIVE BOOL TRUE indicates that Y has exceeded the given limits (Y_MIN, Y_MAX).