VL-1225/6 Analog Input/Output Board
4-5
Input Binary Format (11-Bit Resolution)
Binary format is used only with the unipolar 0 to +10V input range. 11-bit binary format divides the full
10 Volt analog input range into 2048 steps of 4.88 mV each. The code 0000H is associated with an analog
input voltage of 0 Volts (ground). The largest code (07FFH) describes the highest voltage, i.e., +9.9951
Volts. All codes are considered positive. The upper five bits of the Data High register are all zeros.
The formulas for calculating analog or binary digital values are given by:
Analog
Digital =
————
Analog = Step
×
Digital
Step
Where:
Analog
= Applied voltage
Digital
= A/D Conversion Data
Step
= 0.00488281
Sample values are shown in the table below:
Input
Data
Data
Voltage
(Hex)
(Decimal)
Comment
+10.0000
—
—
Out of range
+9.9951
07FF
2047
Maximum voltage
+5.0000
0400
1024
Half scale
+2.5000
0200
512
Quarter scale
+1.2500
0100
256
Eighth scale
+0.00488
0001
1
1 LSB
0.0000
0000
0
Zero (ground input)
Figure 4-3. Binary Data Format (11-Bit Resolution)
Registers – Analog Input Registers
