A/D Data Format - NuDAQ PCI- 9113A User Manual

5.1.5

A/D Data Format

The range of A/D data read from the FIFO port is from 0 to 4095. As the
A/D gain is 1, the A/D signal range is roughly -10V ~ +10V or -5V~+5V
(bi-polar) and 0V~+10V (uni-polar). The relationship between the voltage
and the value is shown in the following table:
A/D Data (Hex)
Direct Binary
FFF
C00
801
800
7FF
400
000
A/D Data (Hex)
2's
Complement
7FF
400
001
000
FFF
C00
800
The formula between the A/D data and the analog value is
Direct Binary Coding:
Bipolar 10V
Voltage = ( AD_Data * 20 ) / ( 4096 * gain ) – (10 / gain)
Bipolar 5V
Voltage = ( AD_Data * 10 ) / ( 4096 * gain ) – (5 / gain)
Unipolar +10V :
Voltage = ( AD_Data * 10 ) / ( 4096 * gain )
Unsigned
Decimal Value
4095
3072
2049
2048
2047
1024
0
Signed
Decimal Value
2047
1024
0001
0000
-0001
-1024
-2048
:
:
Voltage (Volts)
Bipolar
10V 5V
+9.9951 +4.9975
+5.0000 +2.5000
+0.0049 +0.0025
0.0000 0.0000
-0.0049 -0.0025
-5.0000 -2.5000
-10.0000 -5.0000
Voltage (Volts)
Bipolar
10V 5V
+9.9951 +4.9975
+5.0000 +2.5000
+0.0049 +0.0025
0.0000 0.0000
-0.0049 -0.0025
-5.0000 -2.5000
-10.0000 -5.0000
Operation Theorem 31
Unipolar
0~10V
+9.9951
+7.5000
+5.0049
+5.0000
+4.9951
+2.5000
0.0000
Unipolar
0~10V
+9.9951
+7.5000
+5.0049
+5.0000
+4.9951
+2.5000
0.0000