Knick Stratos Pro A401B PH, User Manual

Page: 107 / 196

107
Controller Functions
Pulse Length / Pulse Frequency Controller
Pulse length controller (PLC)
The pulse length controller is used to operate a valve as an actuator.
It switches the contact on for a time that depends on the controller
output. The period (pulse length) is constant. A minimum ON time of
0.5 sec is maintained even if the controller output takes correspond-
ing values (Y=0: Off).
Output signal (relay contact) of pulse length controller
ON time (Y = 80 %)
ON time (Y = 20 %)
Pulse length
1
0
1
0
Pulse frequency controller (PFC)
The pulse frequency controller is used to operate a frequency-
controlled actuator (metering pump). It varies the frequency with
which the contacts are switched on. The maximum pulse frequency
[pulses/min] can be defined. It depends on the actuator.
The contact ON time is constant. It is automatically calculated from
the user-defined maximum pulse frequency:
Output signal (relay contact) of pulse frequency controller
ON time
Pulse frequency (Y = 20%)
Pulse frequency (Y = 80%)
1
0
1
0