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6. Operation and function description
Optical response, display flashing
The switching on of one or more setpoints can also be set to trigger a flashing of the display to
enhance the optical response.
Example:
Let us assume the threshold for flashing of the display is set at setpoint 2. If setpoint 1 is
exceeded and setpoint 2 is not, the setpoint
LED 1
lights up permanently. If setpoint 2 exceeds
the threshold, the 7-segment display will start to flash, setpoint 1 will light up permanently and
setpoint LED 2 will flash.
The flashing enhances the optical response and the operator sees immediately that an important
threshold has been exceeded with this unit.
6.3 Analog output
The analogue output is used to pass on a measured value. The selection of the signals happens
under program number 23, so PN23=0 corresponds to the 0-10 V signal and PN=1 corresponds
to the 0-20 mA signal. The analogue output is parameterised via the two program numbers
PN20 end value
(full scale) and
PN21 initial value
(offset). With the offset value, the value is
set at which the analogue output shows its minimum value (e.g. 4 mA) and with the full scale, the
value at which the output shows its maximum value (e.g. 20 mA).
It is possible in this way to rescale the input signal of a measuring transducer or even to convert
it into another standard signal.
The analogue output can be deactivated or activated via the
PN22 control value
. Furthermore,
the analogue output signal can either be allocated to the
current value
(with possible taring),
the
min-value
, the
max-value
, the
Hold-value
or the
absolute value
(without possible taring).
The analogue output is updated in the cycle of the measuring time (PN14) and has, at maximum,
a resolution of 12bit (4096 dots) and, at minimum, the resolution of the selected output range
PN20 – PN21. In other words, if the difference between PN20 and PN21 is less than 4096, the
resolution of the analogue output is reduced to PN20–PN21 dots!
6.4 Digital input
With the digital input, a wide variety of special functions can be triggered in the unit. These
include various taring and calibration functions, the Hold-function and switching over of the
display mode. The digital input can either be controlled actively with a 24 VDC signal or
passively via a potential-free contact.
6.4.1 Event counter
Since a change made to the configuration opens the door to access calibratable areas, changes
are recorded in an event counter. The event counter counts only when a change is made to the
relevant configuration sections. This is displayed when the system is started up, as e.g.
"C.0023", in order to allow the operating staff and quality management staff to check the
configuration status.
6.4.2 Taring or calibration
Taring or calibration can be carried out via the 4th key on the front or the digital input on terminal
12.
The unit can, on being switched on, be set to various modes via program numbers. Furthermore,
it is possible to differentiate between the evaluation of the key on the front and the digital input.
The tare key on the front and the digital input are interrogated independently of one another. For
taring, the 4th key, the digital input or both in parallel can be used.
