4. Functions
54
AD12-8(PM)
-
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) / Reso 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-volt range.
Voltage
Conversion data (12-bit)
Voltage
Conversion data (16-bit)
+9.995V
4095 +9.99970V
65535
:
: :
:
0.005V
2049 0.00030V
32769
0V
2048 0V
32768
-0.005V
2047 -0.00030V
32767
:
: :
:
-10.000V
0 -10.000V
0
Ex.: When input data 3072 is input at a resolution of 12-bit in the ± 10-volt range
Voltage = 3072
×
(10 - (-10)) ÷ 4096 + (-10)
=
5.0
