2N M2M Solution 2N SmartCom - User Manual 1.9.0 User Manual
Page 28
28
works in the whole range and deviations may occur from the actual value measured on
the input. If you, in this situation, set Threshold low to 0V and Threshold high to 10V
on the input, the terminal will be calibrated for 10V precisely. For 0 on the input, the
AT command will return 0. For 10, we obtain 100. Thus, the calibrated input can be
considered 0 - 100% of the calibrated range.
The red lines mean that the input has been calibrated to the interval of 3 to 8V, i.e.
–
to the range of 5V. This range now represents new measurement limits. If you apply
3V or less on the input, you are in the calibrated min area and the AT command will
return 0. If you apply 8V or more, you are in the calibrated max area and the AT
command will return 100. This means that the measured range width has narrowed by
50% and 0 - 100% is now mapped to the input range of 3 - 8V.
The blue line is an example of measuring in the calibrated range of 0 to 10V. Apply
–
precisely one half of the calibrated voltage, i.e. 5V, to the input. The AT command will
return 50, i.e. one half of the 0 - 100 range again. In this case, 5V is the centre of the
calibrated range. If, however, the range was shifted, the value would be shifted too as
shown below.
The yellow line shows the case that 7V is applied to the input. In case you measure
–
7V in the calibrated 10V range, the AT command will return 70 as 70 represents 70%
of the calibrated range. But if the range is just 3 to 8V as in the red case, 7V will
represent 80% of the calibrated range of 5V and the AT command will return 80.
If you use the calibrated input for reading logic values, keep in mind that the
calibrated area is considered unstable. Values lower than the set minimum
No value is
will be 0 and those exceeding the maximum will be 1.
guaranteed in an unstable area and a spurious state change may occur any time
in the interval. Practically, the decisive level is near the middle of the set interval.