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Elektronik GmbH
Page 32 of 45
POS-124-*-PDP-1121
13.02.2013
5.2.27
MIN / MIN2 (Overlap compensation)
5.2.28
MAX1 / MAX2 (Limitation)
5.2.29
TRIGGER (Response threshold for the MIN parameter)
Command
Parameters
Unit
Group
MIN1:I
X
MAX1:I
X
TRIGGER1 X
MIN2:I
X
MAX2:I
X
TRIGGER2 X
i= A|B
x= 0… 6000
x= 3000… 10000
x= 0… 4000
x= 0… 6000
x= 3000… 10000
x= 0… 4000
-
0,01%
0,01%
0,01%
0,01%
0,01%
0,01%
STD
The output signal to the valve is adjusted by means of these commands. A kinked volume flow character-
istic is used instead of the typical overlap step for the position controls. The advantage is better and more
stable positioning behaviour. At the same time, non linear volume flow characteristics can also be adjust-
ed with this compensation
8
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CAUTION
: If there should also be adjustment options for dead zone compensation on
the valve or valve amplifier, it must be ensured that the adjustment is performed either at
the power amplifier or in the module.
If the MIN value is set too high this has an effect on the minimum speed, which can then
no longer be adjusted. In extreme cases this leads to oscillation around the controlled
position.
MAX:A
MIN:A
MIN:B
MAX:B
Input
O
u
tp
u
t
flow linearization
standard deadband compensation
TRIGGER value
8
Various manufacturers have valves with a defined linear curve: e.g. a kink at 40 or 60 % (corresponding to 10% in-
put signal) of the nominal volume flow. In this case the TRIGGER value should be set to 1000 and the MIN value to
4000 (6000).
If zero lapped or slightly underlapped valves are used, the volume flow gain in the zero range (within the underlap) is
twice as high as in the normal working range. This can lead to vibrations and jittery behaviour. To compensate for
this, the TRIGGER value should be set to approximately 200 and the MIN value to 100. The gain in the zero point is
thus halved and a higher overall gain can often be set.
