SIGMATEK AI 022-1, Operating Manual

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AI 022-1 S-DIAS STRAIN GAUGE INPUT MODULE
Page 22 04.11.2020
7.4 Setting the FilterDepth
When setting the filter depth it has to be cared, that also the conversion time depends on it.
Calculating the ADC data rate fADC (with fCLK = 4.92 MHz) for the sinc 4 filter:
fADC = fCLK / (4 * 1024 * AI[1-2]FilterDepth)
Calculating the ADC data rate fADC (with fCLK = 4.92 MHz) for the sinc 3 filter:
fADC = fCLK / (3 * 1024 * AI[1-2]FilterDepth)
This results in the conversion time tSETTLE: tSETTLE = 2/ fADC
Calculation of the cut-off frequency f3DB: f3DB = 0,24 * fADC
Ex.: Sync 4, filter depth 5 : Conversion time = 9 ms; cut-off frequency = 57.7 Hz
7.5 Setting the Force Sensor
1. The gain of the ADC is set correctly according to the data sheet of the sensor. The mod-
ule should be set in such a way that the range of the force transducer used makes the
most of the value range of the ADC without exceeding it.
2. Zero point calibration (tare) of the sensor with AI[1-2]OpMode - 6. This sets AI[1-2]Off-
setZeroScale.
3. Final deflection calibration: The sensor is loaded with the maximum force used and with
AI[1-2]OpMode - 7 the full scale value in register AI[1-2]OffsetFullScale is defined. The
calibration of the full deflection is only possible between 50 and 100 % of the positive
measurement range.