ABB REM 54 Series - Transducer Supervision; Signal Filtering; Input Scaling;Linearization

58
1MRS750915-MUM
Machine Terminal
Technical Reference Manual, General
REM 54_
5.1.9.3. Transducer supervision
The measuring signal level of each transducer is constantly supervised. If the
measured signal falls more than 4% below or rises more than 4% over the specified
input signal range of a particular channel, the transducer or the transducer wiring is
considered to be faulty and the channel-specific invalid signal is immediately
activated. The invalid signal is deactivated as soon as the transducer signal is within
the valid range.
When necessary, the valid measuring range may be narrower than the default
-4...104% of the selected measuring range. A narrower range can be defined by
means of the parameters Input high limit and Input low limit that can
be found in the menu Configuration/RTD1/Input #.
When an input is configured for resistance or temperature measurement, the internal
excitation current generator forces a current pulse through the measuring circuit
when the input is sampled. If the actual current level does not match the programmed
level due to too high impedance in the circuit, the invalid signal is immediately
activated. The invalid signal is deactivated as soon as the circuit resistance is low
enough.
5.1.9.4. Signal filtering
Short disturbances on an input are eliminated by signal filtering. The filter time,
which defines the step response time, is set for each transducer input of the machine
terminal by the Filter time parameters in the menu Configuration/
RTD1/Input #. The filtering algorithm is a so-called median filter which shows
no reaction to interference spikes but levels out directly on permanent changes.
5.1.9.5. Input scaling/linearization
1
The user can scale each RTD/analog input linearly or non-linearly by constructing a
separate linearization curve for each input. The name implies the typical use, i.e. the
linearization of not directly supported non-linear sensors. The curve consists of at
least two (for linear scaling) and up to ten points, where the x-axis of the curve is 0
Parameter Values Default
Input low limit -4...104% -4%
Input high limit -4...104% 104%
Parameter Values Default
Filter time 0 = 0.4 s
1 = 1 s
2 = 2 s
3 = 3 s
4 = 4 s
5 = 5 s
5 s
1. Not supported yet