Contec F&eIT Series, Руководство пользователя

Страница: 58 / 69

5. Using the Memory Address Map
ADI16-4(FIT)GY
53
Basic Input Data Area
The basic input data area, which is a 128-byte (80h) area beginning with address 304000h,
corresponds to a given Device ID.
The starting address can be determined according to the following expression:
Starting address = 3 80h x (Device ID)
Table 5.4. Basic input data area
Address (h) Area Item Size Access type
Starting a 00 CH0 Analog input value 2 R
Starting a 02 CH1 Analog input value 2 R
Starting a 04 CH2 Analog input value 2 R
Starting a 06 CH3 Analog input value 2 R
Starting a 08
to Starting a 7F Reserved 120
Analog input value
Analog input values are stored as Little Endians.
Table 5.5. Analog input value
D7 D6 D5 D4 D3 D2 D1 D0
+00h A7 A6 A5 A4 A3 A2 A1 A0
+01h A15 A14 A13 A12 A11 A10 A9 A8
The A/D conversion is performed on a channel-by-channel basis, with a timing that reads analog input
values; the results are stored two bytes at a time. For this reason although there is data compatibility
between the high and low bytes, there is no synchronization between channels.
Conversion formula:
input voltage (V) = analog input value x span / 2
16
– offset
Table 5.6. Conversion coefficients
Analog input value Offset Span
-10V to + 10V 10 20
0mA to 20mA 0 20