Burster 9180, Manual

Page: 56 / 109

Model 9180
burster
Digital Panelmeter
Page 4-12
4.2.2 Function description
To guarantee adaptation to customer-specific requirements, the limit value alarm can be
activated individually or in various combinations.
1. Independent alarms
Independent alarms are triggered if the display value reaches the switching point value
programmed by the user.
For the programming of this kind of alarm you also have to determine the following
parameters:
a. Activiating mode
HI/LO
In "
HI
" mode the output is activated if the display value exceeds the value of the switching
point. In the "
LO
" mode the output is activated if the display value drops below the value of
the switching point.
b. Time delay or hysteresis
All alarms can be provided with a switching delay or hysteresis. The switching delay
commences, when the display value exceeds or drops below a fixed value. There are two
possibilities when using time delay with hysteresis:
the asymmetrical hysteresis delays
the deactivation side of the output while the symmetrical hysteresis affects both sides of the
switching point.
The switching delay can be programmed in seconds from 0 up to a maximum displayable
value.
The hysteresis can be programmed in points within the entire display range. The position
of the decimal point is determined by the previously set scaling parameter.
Figures 4.2.2a and 4.2.2b show the time delay realized by the timer circuit (
dly
) and by the
asymmetrical hysteresis (
hys-1
) of two alarms (
SET1
and
SET2
). They are programmed for the
activation in the respective modes
HI
(
OUT1
) and
LO
(
OUT2
).
hys-1
hys-1
SET1
SET2
OUT1
OUT2
dly
dly
dly
dly
SET1
SET2
OUT1
OUT2
Fig. 4.2.2a Switching delay Fig. 4.2.2b A s y m m e t r i c a l
hysteresis