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Operation
Control and fine optimisation of the set parameters with a recorder
Fig. 32:
A
Actual value
B
Time
Actuating signal outputs (R237 ... R2310)
Each control contact outputs a cyclical signal whose intensity corresponds to the controller's
manipulated variable. A distinction is made according to the type of signal cycle:
• Pulse length modulation
The bigger the calculated manipulated variable is, the longer the contact affected remains
picked up. The period T can be adjusted between 0.5 and 99 s (field R238). Outputs with
pulse length modulation are used to activate solenoid valves.
• Pulse frequency modulation
The bigger the calculated manipulated variable is, the higher the switching frequency of the
contact affected. The maximum switching frequency 1/T can be set between 60 and 180 min
1
. The on-time t
s for 60 min
are used to activate directly controlled solenoid dosing pumps.
Fig. 33:
A
Contact 1 = on, 0 = off
B
Time [s] t
46
A
1
A
3
A
Optimisation of settings T
and K
n
is constant. It depends on the set maximum frequency and is approx. 0.5
ON
-1
and approx. 170 ms for 180 min
A
t
1
t
2
1
0
T
Signal of a pulse-length modulated controller contact (left) and of a pulse-frequency modulated
controller contact (right)
= t
t
= t
1
on
2
off
A
B
A
B
5
B
p
1
T
too small
n
2
T
too large
n
3
K
too large
p
-1
. Outputs with pulse frequency modulation
A
t
1
1
0
t [s]
T
1
T
Period length
T
T
Impulse period length (impulse freq. 1/T
1
2
OPM223/253
2
B
4
B
C07-OxM2x3xx-05-06-00-xx-004.eps
4
K
too small
p
5
Optimum setting
t [s]
T
2
C07-OLM2x3xx-05-06-00-xx-005.eps
and 1/T
)
1
2
-
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