98
Differential control
= keeps the temperature constant between two sensors.
Keeping the temperature difference constant between S1 and S2, for instance, allow for
“shifting” operation of the collector. If S1 drops due to lower irradiation, the difference
between S1 and S2 thus drops. The control unit then lowers the speed, which increases the
dwell time of the medium in the collector and hence the difference between S1 and S2.
Example:
DC N12
D
ifferential
c
ontrol in
n
ormal operation between sensors S
1
and S
2
.
(ex works = --)
Setting range: DC N12 to DC N65, DC I12 to DC I65)
DC -- = differential control is disabled.
DVD 10
The
d
esired
v
alue for
d
ifferential control is
10K
. In the example, the temperature
difference between S1 and S2 is maintained at 10K.
Warning
: DVD always has to be greater than the switch-off difference of the
basic function. If the DVD is lower, the basic function of pump release blocks
before the speed control has reached the desired value. (ex works = 10K)
Setting range: 0.0 to 9.9K in increments of 0.1K,
10 to 99K in increments of 1K
If the absolute value control (maintaining a sensor) and the differential control (maintaining
the difference between two sensors) are both active, the slower of the two speeds “wins out”.
