HYDAC CMU 1000 - Manual (Page 90)

Condition Monitoring Unit CMU 1000 Page 90
Revised 17.12.2009 HYDAC ELECTRONIC GMBH Mat.-No.: 669749
7.3.15 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
differential 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 quantizing
distortion. This means that the digitization causes the value fluctuate
in terms of resolution. For example, with a 12-bit resolution, a value
of 600 bar that was resolved with 12 bit will fluctuate back and forth
by 0.15 bar. If the differential quotient is formed now every
millisecond, then this quantizing distortion will be amplified by a
factor of 1000. That 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. Nonetheless, no pure median value formation will 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)