IM-P693-02
EMM Issue 2
14
LCR2251 Level Controller
B
A
5.5 Setting the measuring range
Fig. 7 LP20/21 with a PA420 level transmitter.
Important
Set the upper and lower end of the measuring range only in the transmitter.
5.6 Additional information on control parameters
Parameter
Control deviation
Control valve
Proportional
band
Pb
Larger
Large remaining deviation
Responds slowly
Smaller
Small remaining deviation
Responds quickly and may continually
open/ close
Example
Measuring range 100% = 200 mm of sightglass Setpoint SP = 80 % of measuring
range = 160 mm
Proportional band Pb = +/- 20% of setpoint = +/- 16% = +/- 32 mm
If the measuring range is 100% (200 mm) and the setpoint is 80% (160 mm), the
proportional range will be +/- 16% (+/- 32 mm) or in the range of 128 to 192 mm.
Integral
action time
ti
Larger
Slow correction of deviations
Responds slowly
Smaller
Fast correction of deviations, control
loop may tend to overshoot
Responds quickly
A
Lower end of measuring range, adjustable
B
Upper end of measuring range, adjustable
C
Measuring range [mm] = xxx %
D
Maximum installed length at 238 °C
Set the lower and upper ends of the measuring range for your fill level
measurement. The result is the measuring range C.
Please calculate this measuring range in percent.
C
D
25 mm
