Hysteresis For Measured Value Monitoring - Festo CPX-AP-I-4AI-U-I-RTD-M12 Instructions & Operating

Analogue value display
6.6

Hysteresis for measured value monitoring

The diagnostics for measured value monitoring (limit value, signal range) are provided with hysteresis.
Hysteresis avoids repeated diagnostic messages if the measured value is within the limits of the dia-
gnostic thresholds.
The diagnostic messages behave as follows with a defined hysteresis:
– Limit monitoring:
The diagnostic message is only sent if the defined lower or upper limit is below or exceeded by
one half of the hysteresis value. The diagnostic message is sent if the lower or upper limit is again
below or exceeded by one half of the hysteresis value.
– Signal range monitoring:
The diagnostic message is issued immediately, without the measured value being exceeded by
half the hysteresis. The diagnostic message is cancelled if the signal range again exceeds or is
below by one half of the hysteresis value.
The hysteresis is set via parameter 20046 è 10 Parameterisation.
The set hysteresis value corresponds to the entire positive and negative hysteresis range, i.e. a value
of 100 means measured value ±50.
The hysteresis value is converted as follows depending on the signal range:
– Voltage measurement:
A hysteresis value Z1 mV, that is, a value of 100 means 100 mV hysteresis.
– Current measurement:
A hysteresis value Z0.001 mA, i.e. a value of 100 means 0.1 mA hysteresis.
– Resistance measurement:
A hysteresis value Z0.1 Ω, i.e. a value of 100 means 10 Ωhysteresis.
1 Hysteresis value
2 Lower limit
3 Upper limit
Fig. 10 Hysteresis for measured value monitoring
18
4 Diagnostics off
5 Diagnostics on
Festo — CPX-AP-I-4AI-U-I-RTD-M12 — 2020-03