GESTRA LRR 1-52, Original Installation & Operating Manual

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62 LRR 1-52, LRR 1-53, URB 55 - USA - Installation & Operating Manual -
850703-00
Configuring the conductivity controller
Setting the control parameters
Parameter Control deviation Control valve
Proportional
band
Pb
> larger Large remaining deviation Reacts slowly
< smaller Small remaining deviation
Reacts quickly and may open/close
continually
Example:
Measuring range 0 to 3000 ppm (0 to 6000 µS/cm)
Set point SP = 1500 ppm (3000 µS/cm)
Proportional band Pb = +/- 20% of set point = +/- 300 ppm (600 µS/cm)
With the measuring range and set point mentioned above, the proportional band
is then +/- 300 ppm (600 µS/cm) or in the range from 1200 ppm (2400 µS/cm)
to 1800 ppm (3600 µS/cm).
Reset time
Ti
> larger Slow correction of deviations Reacts quickly
< smaller
Fast correction of deviations, the control
loop may tend to overshoot
Reacts slowly
Dead
band
> larger
Correction of deviations starts with a
delay
In this range, the manipulated variable
does not change.
Only reacts when the control
deviation is larger than the “dead
band”.
< smaller Correction of deviations starts rapidly
Valve runtime
Tt
Establish the real valve runtime, e.g.,
from “Closed” to “Open” (0 - 100%).
Operating
position Defined opening of the continuous
blowdown valve. Closes on standby.
Fig. 23
Open the control parameter
screen.
Guide to setting control parameters