Manual
Version
Page
DB04A
EN A1-9
PKP Prozessmesstechnik
27
The decimal point is located behind the number display field. Once you entered a decimal
point followed by another number, the dot changes into an “E”. If you press this you can
enter the scientific notation, for instance 1.0E-3 = 0.001 or 2.2E2=220.
Threshold:
Threshold is the activation value. If f.i. you selected a high alarm, the alarm will
be active when the flow value comes over the Threshold value. The value is entered in flow
engineering values that the unit is set for at that moment (f.i. in mln/min). If you change the
engineering units of the unit in a later stage, the Threshold value will automatically adjust
itself to the new flow unit.
Please note that there is no limit to the value you can enter as a threshold. Please
double check your entered value.
Hysteresis:
The hysteresis
is the difference between
the value where the alarm
turns ON from turning OFF
and the value where it turns
OFF from turning ON.
This difference is defined in
% of full scale. In figure 9
an example of a 50%
threshold value high alarm
with a 10% hysteresis. The
blue line in the top graph
reflects the gas flow, the
vertical dotted lines the
switching points.
The blue area’s in the
graph below is where the
alarm is activated.
The reset is set to
automatic.
Please note that you can enter a value of 100% as hysteresis value. If you do that the
alarm will no longer switch off
.
Alarm delay:
The alarm delay is a delay in milliseconds between the moment the alarm
situation occurs to the moment that the alarm is activated. It can be set from 20 to 9999999
msec (=2.777 hr).
Alarm duration: (Note: This function is only active if the reset is set to automatic)
The alarm duration is minimum time that the alarm is active after it is activated. It can be set
from 100 to 9999999 msec (=2.777 hr)
Reset source:
The alarm can be reset in different ways. Below a list of the 4 possible
settings:
Figure 8: Explanation hysteresis
