HYDAC CSI-F-10 - Manual (Page 90)

GSM Radio Module CSI-F-10 Page 90
Status 29.01.2009 HYDAC ELECTRONIC GMBH Part.-Nr.: 669752
9.3.15 Differential Quotient
The Differential quotient function supplies the derivation of the input
value over time at the output. The output is always calculated with
the unit of seconds. This means that an increase of the input value
from 5 to 6 in one second will yield an output value of 1.
The differential quotient is formed and filtered numerically by the
difference quotient. This filtering is necessary for the following
reasons:
In view of the fact that the input values usually arise from a
quantized measured value, e.g. in connection with the digitization of
an analog quantity, these values will have a so-called quantization
noise. This means that the digitization causes the value to fluctuate
in terms of the resolution. For example, for 12 bit resolution, a value
of 600 bar which has been expressed in 12 bit resolution, fluctuates
back and forth by 0.15 bar. If the differential quotient is now
generated every millisecond, this quantization noise is amplified by a
factor of 1000. This means that, without filtering, the output would
jump back and forth between + and - 150 bar/s.
The filter can be set with the Filtering parameter. The setting
corresponds thereby to the time range during which the filtering
takes place. However, a pure median value formation will not be
used as a filter, but rather a special algorithm instead.
The following settings are possible:
• switched off, • 200 ms, • 1 second • 5 seconds.
Inputs: x
1
: (Numerical)
Outputs: y: (Numerical)
Parameters: p
1
:
Filtering
(entry list)