Measuring Ranges - Siemens FIDAMAT 6 Operating Instructions Manual

4.3.3

Measuring ranges

Measuring ranges/spans
The desired spans (start-of-scale and full-scale values of measuring range) can be specified
with function 41. The start-of-scale and full-scale values are assigned to the analog current
values 0/2/4 mA and 20 mA.
If you enter the same values for the start-of-scale and full-scale of a measuring range, this
range is considered as non-existent. Assign the smallest measuring span (MS) to measuring
range 1 and the next larger one in each case to measuring ranges 2 – 4. In general, the
following applies to the assignment: MS1 < MS2 < MS3 < MS4.
Zero setpoint
Enter the setpoint of the zero point under function 22. It applies to all measuring ranges.
Zero calibration
You calibrate the zero point with function 20. The device displays both the setpoint and
actual value.
Electronically suppressed zero
If the start-of-scale value (ppm, vol%, etc.) is not at a concentration of zero, this is called a
measuring range with suppressed zero, e.g. 200-300 ppm THC. In this case, 200 ppm is the
start-of-scale value, 300 ppm the full-scale value and the span is 100 ppm.
Channels with electronic zero suppression are physically identical with non-suppressed
zeros. They only differ in the configured measuring ranges and setpoint for the suppressed
zero (e.g. 200 ppm THC). The characteristic is stored from zero up to the full-scale value of
the characteristic (in accordance with the rating plate). You can reconfigure devices with
non-suppressed zeros by subsequently reassigning these parameters to suppressed zeros
(functions 22 and 41). Note, however, that influences such as noise, temperature errors and
pressure errors increase by the factor
F = (full-scale value of smallest measuring range) / (full-scale value of smallest measuring
range - start-of-scale value)
. "F" should not exceed a value of "7" here. In general, we recommend that the smallest
span not be increased by more than approximately 30%.
FIDAMAT 6
Operating Instructions, 03/2018, A5E00222135-03
Commissioning
4.3 Commissioning and operation
49