Output regulator Setting the regulator
Regulator behaviour The load regulator attempts to adjust the actual value to the set-point.
A direct relationship between the internal load and the boiler's temperature
is assumed. In other words, the higher the internal load, the faster the
boiler's temperature rises.
The load regulator would not function if the curves were programmed
otherwise.
Four parameters determine the regulator's behaviour:
Readjustment interval
The readjustment interval determines how often the deviation is monitored
and a new adjustment calculated.
Example: a value of 10 in parameter 808 means that this procedure is
carried out every ten seconds.
The value should correspond to the control section's lag time.
P-factor
The proportional factor acts directly on the deviation, i.e. the difference
between the set-point and the actual value. The set factor is divided by 10
for the adjustment.
Example: with a set-point of 500, an actual value of 460 and a P-factor of
12, this results in a proportionality fraction of +48.
( 500 - 460 ) C 12
_______________
10
I-factor
The integral factor is calculated from the momentary deviation and the
previous deviation from the set-point. The set factor is divided by 10 for the
adjustment.
Example: with a set-point of 600 and a momentary actual value of 620, this
results in an actual deviation of -20. Assume the actual value was 622 at
the last calculation, i.e. before the set readjustment interval, giving a
previous deviation of -22. With the factor set to 5, the adjustment would be
-21 points (-42 x 0.5).
D-factor
The difference factor is calculated from the change in the actual value. It is
also divided by 10.
Example: the previous actual value (before the readjustment interval) was
600. The current actual value is 605. With a D-factor of 50, this results in a
D-fraction of -25 points (-5 x 5).
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