Checking and fine tuning of parameter settings using a recorder
Actuating signal outputs (R237 ... R2310)
Each control contact outputs a clocked signal whose integral corresponds to the controller’s
manipulated variable. A distinction is made according to the type of signal clock:
•
Pulse length modulation
The greater the calculated control output,
the longer the contact in question remains
picked up. The period can be adjusted
between 0.5 and 99 s. Pulse-length
modulated outputs are used to control
solenoid valves.
•
Pulse frequency modulation
The greater the calculated control output,
the higher the switching frequency of the
contact. The maximum switching
frequency 1/T can be adjusted between
60 and 180 rpm. The ON period t
ON
is
constant. Pulse frequency outputs aid the
control of directly driven magnetic dosing
pumps.
REGEL02.CDR
Actual
value
Actual
value
Actual
value
Actual
value
Actual
T
n
too small
T
n
too big
K
p
too big
K
p
too small
Optimal setting
Time
Time
Time
Time
Time
Fig. 5.9
Setting optimisation
T
n
and K
p
IMPULS.CDR
t
ON
t
OFF
On
Off
Period T
Time [s]
Contact
Contact
t
ON
T1
T2
Time [s]
On
Off
Fig. 5.10
Signal of a pulse length
modulated (left) and a
pulse-frequency
modulated control contact
(right)
Instrument configuration
Liquisys M COM 223 F / 253 F
36
Hauser
