Burkert Type 8620 - Manual (Page 64)

mxCONTROL Type 8620
Page 64
Special input function
There is special root extraction function available, e.g. for adapting special flow sensors. Therefore the
following function is applied to the scaled value.
with Scal- (low scaling value)
Scal (high scaling value)
− − + − + − − =
Scal Scal Scal Scal PV new PV ) )( ( ,
PV (scaled process value)
Refer also to Figure 18: Root function.
Special input function: Root extraction
0
200
400
600
800
1000
0 200 400 600 800 1000
Process value
N
e
w p
ro
c
ess
v
a
lu
e
No special function Root extraction
Figure 18: Root function
Low Pass Filter
To minimise the effect of spikes and fast transients acting on the device's external cabling and
possibly causing interferences, a low pass filter (PT1) is employed.
The setting is done via the selection of the filter stage.
Filter stage Corresponds to limit frequency [Hz] Effect
0 10 Lowest filter effect
1 5
2 2
3 1
4 0,5
5 0,2
6 0,1
7 0,07
8 0,05
9 0,03 Greatest filter effect
Table 7: Filter stage and limit frequency
(Process Value) Alarm
Refer to Figure 15:
This function actuates the common alarm output whenever a controlled process value exceeds the
adjustable upper and lower alarm limits.