The PV_NORM function normalizes the Output of CRP_IN following formula:
PV_FAC has a default of 1 and PV_OFF a default of 0.
The difference between the setpoint and process variable is the error signal. To suppress
a small constant oscillation due to the manipulated variable quantization (for example due
to a limited resolution of the manipulated value by the actuator valve), a dead band is
applied to the error signal (DEADBAND). If DEADB_W = 0, the dead band is switched off.
The FB operates without a position feedback signal. The I action of the PI algorithm and
the assumed position feedback signal are calculated in one integrator (INT) and com-
pared with the remaining P action as a feedback value. The difference is applied to a
three-step element (THREE_ST) and a pulse generator (PULSEOUT) that creates the
pulses for the actuator. The switching frequency of the controller can be reduced by
adapting the threshold on of the three-step element.
A disturbance variable can be fed forward at the DISV input.
Complete Restart/Restart
n FB42 CONT_S has a complete restart routine that is run through when the input
parameter COM_RST = TRUE is set.
n All other outputs are set to their default values.
The block does not check for errors, so no error Information is output.
Error Signal
PI Step Algorithm
Feedforward Control
Modes
Error Information
VIPA SPEED7
Standard
PID Control > FB 42 - CONT_S - Step Control
HB00 | OPL_SP7 | Operation list | en | 18-30 845
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