HYDAC CMU 1000 - Manual (Page 89)

Condition Monitoring Unit CMU 1000 Page 89
Revised 17.12.2009 HYDAC ELECTRONIC GMBH Mat.-No.: 669749
7.3.13 Decade Logarithm
The Decade logarithm function supplies the logarithm of the input
value at base 10 at the output.
If the input value is negative or 0, then the value 0 will be supplied at
the output and an error flag will be set. One can react to this
situation with the Error event function (see Chap. 7.2.8).
If a negative input can occur in everyday practice, then you should
structure the corresponding behavior in accordance with your
preferences with the functions Absolute value, If-then-else and Less
than (see Chap.
7.3.6, 7.4.4 and 7.6.5).
Inputs: x: (Numerical)
Outputs: y: (Numerical)
Parameters: -
7.3.14 Integral
The Integral function supplies the integral of the input value over
time at the output. The output is always calculated with the unit of
seconds. This means that the input value 6 causes the output to
increase every second by 6. The trapezoidal rule is applied to make
the calculation.
The function still has a Boolean reset input. If the value "1" is
pending there, then the value "0" will be set up at the output.
Furthermore, the integral function also has an automatic anti-wind-
up mechanism. It is with this that a parameterizable Lower limit and
Upper limit
are set for the output.
This function adopted from control engineering has the following
background:
If a control variable is not achieved, then the I ratio continues to
integrate further. The controller then may require under certain
circumstances a very long time to exit this range again if the
actuating variable reverses its algebraic sign. This can lead to very
unstable behavior.
Inputs: x
1
: Input value (Numerical)
x
2
: Reset input (Boolean)
Outputs: y: (Numerical)
Parameters: p
1
:
Lower limit
(Numerical)
p
2
: Upper limit (Numerical)