VIPA SSM-BG41 - Fig. 3-43: Transformating the Analogue Range to the Scaled Range

Functional description and allocation of terminal pins Manual BG41/BG42/BG43
3-56 Rev. 99/49
Transformating the analogue range to the scaled range
A sensor gives an analogue value. The firmware shows this value in the nominal range. The
nominal range is hardware specific and is in the range of -2048 to 2047. You don't want to work
with this values, but you want to predefine your own range, which is directy combined with the
sensor values. The nominal range is shown to a normalized range. With setting the upper and lower
limits the normalized range can be determined. Possible are numbers with a width of maximal
2Byte(2
15
=32768).
To preserve the sensor resolution always choose the possibly greatest numerical range for
normalizing.
effective range of the sensor
-5V
-10V
5V
10V
...
...
nominal range
-2048 2047
normalized range
UG
OG
(min. -32768)
(max. 32767)
effective range of the sensor
0mA
0V
20 mA
10V
...
...
nominal range
0
4095
normalized range
UG
OG
(min. -32768) (max. 32767)
Fig. 3-43: Transformating the analogue range to the scaled range
Example
You set in a sensor (4...20mA), which shows the level of a container holding 30l.
How to define the upper and lower limits?
At 4mA 0l shall be shown. At 20mA 30l shall be shown.
Set 0 for lower limit and 30000 for upper limit (always choose the greatest number).
In case of wire breakage the lower limit will be undershoot and the data handling block will show
an error message.