Endress+Hauser iTEMP TMT 165 FOUNDATION Fieldbus Betriebsanleitung Seite 128

11 Appendix
Index Parameter
24 ALARM_HYS
128
Analogue Input Function Block
Write access with
operating mode
(MODE_BLK)
AUTO - MAN - OOS For entry of the hysteresis value for the upper and lower warning or alarm
limit values. The alarm conditions remain active so long as the measured
value is within the hysteresis.
The hysteresis value affects the following warning and alarm limit values of
the Analogue Input Function Block:
HI_HI_ALM
HI_ALM
LO_LO_ALM
LO_ALM
User input:
Factory default:
2
The hysteresis value relates to a percentage of the range of the parameter
group OUT_SCALE in the Analogue Input Function Block (see page 134).
Example:
The top diagram shows the limit values defined for the warnings LO_LIM and
HI_LIM with their respective hystereses (grey background) and the signal
curve of the output value OUT.
The bottom two diagrams show the behaviour of the associated alarms
HI_ALM and LO_ALM in relation to the changing signal curve (0 = no alarm,
1 = alarm output).
FOUNDATION Fieldbus temperature transmitter
Description
Upper limit value alarm
Upper limit value pre alarm
Lower limit value alarm
Lower limit value pre alarm
0...50%
0.5%
Note!
a = The block output value OUT exceeds the
limit value HI_LIM, HI_ALM is activated.
b = The block output value OUT is below the
hysteresis value of HI_LIM, HI_ALM is deactivated.
c = The block output value OUT is below the
limit value LO_LIM, LO_ALM is activated.
d = The block output value OUT exceeds the
hysteresis value of LO_LIM, LO_ALM is deactivated.
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