Contec ADI12-16(PCI) User Manual page 67

4. Functions
- Data acquisition in ring format
When ring memory is used, data is read always with respect to the current input data write position.
The following sketch shows an image of data acquisition in ring format.
The sampling count obtained is always the number of times of sampling for up to the latest data
(shaded portion below).
The larger the number of samples taken, the older the data item acquired first.
As the ring memory retains data even after that data is acquired, you can fetch the same data any
number of times.
Conversion data
The following equation represents the relationship between input data and voltage.
Voltage = Input data x (Max. range value – Min. range value) ÷ Resolution + Min. range value
The value of resolution for the 12-bit device is 4096; that for the 16-bit device is 65536.
The table below shows the relationship between input data and voltage in the ±10-V range.
Voltage Conversion data (12-bit)
+9.995V
:
0.005V
0V
-0.005V
:
-10.000V
Ex.: When input data 3072 is input at a resolution of 12-bit in the ± 10-V range
Voltage = 3072 x (10 - (-10)) ÷ 4096 + (-10)
= 5.0
60
Voltage
4095 +9.99970V
:
2049 0.00030V
2048
2047 -0.00030V
:
0 -10.000V
Conversion data (16-bit)
65535
: :
32769
0V 32768
32767
: :
0
ADI12-16(PCI)