70 Analog I/O Modules (AD268 / DA264 / TC218)
5. I/O Allocation and Programming PART 3 TC218
5.2 A/D conversion data
The analog signals received by the TC218 are converted into the digital data in this module.
These converted digital data are read by T2 CPU in the batch I/O processing and stored in the
assigned input registers as follows.
XW(n) ........ A/D conversion data for channel 1
XW(n+1) .... A/D conversion data for channel 2
XW(n+2) .... A/D conversion data for channel 3
XW(n+3) .... A/D conversion data for channel 4
XW(n+4) .... A/D conversion data for channel 5
XW(n+5) .... A/D conversion data for channel 6
XW(n+6) .... A/D conversion data for channel 7
XW(n+7) .... A/D conversion data for channel 8
The conversion data stored in the XW register is dependent on the input type as follows.
±
±±
±100mV input:
A/D conversion data
Input voltage Hex adecimal Integer Resolution
Upper limit +102 mV H7 F80 32640
:: :
Full scal e (po siti ve) +100 mV H7D00 32000
:: :
+3.125 µVH0001 1
0 0 V H0000 0
-3.125 µVHFFFF -1
:: :
Full scale (negative) -100 mV H8300 -32000
:: :
Lower lim it -102 mV H 8080 -32640
3.125 µV / bit
+102mV
HC000
-16384
0
H3FFF
16383
+100mV
H7D00
32000
+51.196mV
-51.2mV
-102mV
-100mV
H8300
-32000
Digital value
Analog input
D = 320 × A
D: Digital data
A: Analog signal (mV)
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