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Data Values for Calibratlng Unipolar 10 Volt Range (0 to +10 votts)
Offset (TR7)
Input Voltage = +1.22070 mV
Converter Galn (TR2)
Input Voltage = +9.49829 V
A/D Converled Data
0000 0000 0000
0000 0000 0001
1 1 1 1 0 0 1 1 0 0 1 0
1 1 1 1 0 0 1 1 0 0 1 1
Bipolar Calibration
. Bipolar Range Adjustments: -5 to +5 Volts
Two adjustments are made to calibrate the A/D converter for the bipolar range of -5 to +5 volts. One is the
offset adjustment, and the other is the full scale, or gain, adjustmenr Trimpot TR3 is used to make the offset
adjustment, and trimpot TR2 is used for gain adjustment. Before making these adjustments, make sure that the
junper on P3 is set for lOV and the jumpers on P4 and Pl I are set for +/-.
Use analog input channel I and set it for a gain of 1 while calibrating the board. Connect your precision voltage
source to channel 1. Set the voltage source to 4.99878 volts, shrt a conversion, and read the resulting daia. Adjust
trimpot TR3 until it flickers between the values listed in the table below. Next, set the voltage tD +4.99634 volts, and
repeat the procedure, this time adjusting TR2 until the data flickers between the values in the table.
Data Values for Calibrating Bipolar 10 Vott Range (-5 to +5 votts)
Oftset (TR3)
Input Voltage = -4.99878V
Converter Galn (TR2)
lnput Voltage = +4.99634V
A/D Converted Data
1000 0000 0000
1000 0000 0001
0 1 1 1 1 1 1 1 1 1 1 0
0 1 1 1 1 1 1 ' t 1 1 1 1
Table 5-2 - A/D Converter Bit Weights,
Bipolar, Twos Complement
A/D Bit Weight
ldeal Input Voltage (millivolts)
'5 to +5 Volts
-10 to +10 Volts
1 1 1 1 1 1 1 1 1 1 1 1
-2.44
-4.88
1000 0000 0000
-5000.00
-10000.00
0100 0000 0000
+2500.00
+5000.00
0010 0000 0000
+1250.00
+2500.00
0001 0000 0000
+625.00
+1250.00
0000 1000 0000
+312.50
+625.00
0000 0100 0000
+156.25
+312.50
0000 0010 0000
+ 7 8 . 1 3
+ 1 5 6 . 2 5
0000 0001 0000
+39.06
+78.13
0000 0000 1000
+ 1 9 . 5 3
+39.06
0000 0000 0100
+9.77
+19.53
0000 0000 0010
+4.88
+9.77
0000 0000 0001
+2.44
+4.88
0000 0000 0000
0.00
0.00
5-5
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