This process is used to select the display format depending on which formats are provided in the user program.
It is necessary to differentiate between the electric ranges and the thermocouple or thermowell ranges.
Standardized display of electrical ranges
The values are displayed in standardized units (in % with 2 decimals, also with symbol °/
):
|
Type of range
|
Display
|
|
unipolar range
0-10V, 0-5V, 0-20mA, 4-20mA
|
from 0 to 10000 (0 °/  to 10000 °/  ) |
|
bipolar range
+/-10V
|
from -10000 to +10000 (-10.000 °/  to +10.000 °/  ) |
User-defined display of electrical ranges
The user can select the value range in which the measurements are expressed, by selecting:
-
the minimum limit corresponding to the range minimum: 0 (or - 10000 °/
),
-
the maximum limit corresponding to the range maximum: + 10000 °/
.
The minimum and maximum limits are between -31128 and +31128.
Example:
Use of a 2/20 bar pressure sensor supplying a 0/20 mA signal and having a linear characteristic.
The user is interested in the pressure rather than the current value. The best resolution is obtained by selecting user display:
The user-program then uses values expressed directly in the physical unit, the millibar.
Illustration
Displaying thermocouple and thermowell ranges
With the temperature display format, values are provided in tenths of a degree.
With user display, the user can select standardized display 0..10000 by specifying the minimum and maximum temperatures corresponding to 0 and 10000.
The measurement provided to the application can be applied directly by the user, who can choose between standardized and temperature display formats.
Example:
Thermocouple J connected to a TBX AES 400 module. The user wishes to monitor a temperature range from 200 °C to 600 °C and obtain a result expressed as a percentage of the dynamic range.
In order to do this, select a standardized display format and define the limits:
-
lower limit = 2000,
-
upper limit = 6000.
The measurement accessible by program then falls between 0 and 10000.
For a temperature of 400°C, the module supplies a digital value equal to 5000 as the measurement, i.e. 50 % of the input dynamic range.
Illustration:
