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Analog Configuration

Overview of Analog Configuration Tool

The Analog to Digital Converter ( ADC ) of each channel converts the analog signal from the corresponding sensor to the digital code. The analog input range of the ADC is determined by the reference voltages - UPR2 High and UPR1 Low. The full-scale range of the ADC is equal to UPR2 High - UPR1 Low. Output of the ADC is value from 0 units at UPR1 Low to 1023 units at UPR2 High. SerReg converts these units to the required engineering units by a transformation file. This file is generated by means of Analog Configuration Tool. Analog Configuration Tool can work in two modes: Linear Conversion and Nonlinear Conversion. Linear Conversion mode creates a linear relation between the analog input ( U in ) and the displayed value. This is the most used mode because the most sensors are designed to be linear.Nonlinear Conversion mode is very useful when the sensor has a nonlinear output ( thermistor , RTD ). This mode allows to create a straight-line relation between the physical variable and the displayed value by a linear interpolation. In this case, physical variable must be applied to the sensor.

Convert Mechanism of PIC 16F873A
fig.1 Convert Mechanism

Where U PR1 Low and U PR2 High are determined with PR1 and PR2 resistors.

Main Dialog Box

Main Window of Analog Configuration Tool
fig.2 Analog Configuration Tool

Common controls of Analog Configuration Tool:

redbullet Generate - generates a tranformation file
redbullet Units - name of engineering units as an example: kPa ,C
redbullet Decimal Places - number of digits after the decimal point
redbullet Linear / Nonlinear Conversion - mode select radio buttons

Main modes:

bluebullet Linear Conversion

Linear Conversion ( conversion diagram )

Linear Conversion

Linear Conversion ( conversion diagram )

Linear Conversion

  1. Click on Linear Conversion radio button.
  2. Enter the desired engineering units in Lower Limit ( 0 ) edit box.
  3. Enter the desired engineering units in Upper Limit ( 1023 ) edit box.
  4. Click on Generate button.
  5. In the interface application open the configuration dialog of the corresponding channel and load the generated file by clicking on Convert File button.

bluebullet Nonlinear Conversion

Nonlinear Conversion ( conversion diagram )

Nonlinear Conversion

  1. Connect the desire sensor to SerReg.
  2. Select a COM port and a channel.
  3. Apply physical variable to the sensor that corresponds to the lower calibration point.
  4. In the edit box Value On Display enter the value of the physical variable applied to the sensor and click Set button.You can see the corresponding units ( N ) from SerReg in the static box Value From PIC.
  5. Change the value of the physical variable applied to the sensor and repeat step 4 until reach the upper calibration point.
  6. Click on Generate button.
  7. If you want to edit the entered value, double click on it in the table.
  8. You can change the edit box Value On Display with Step and "+" or "-" buttons.
  9. In the interface application open the configuration dialog of the corresponding channel and load the generated file by clicking on Convert File button.



 

Last modified :
09.04.2006