74 Analog I/O Modules (AD268 / DA264 / TC218)
5. I/O Allocation and Programming PART 3 TC218
5.3 Programming
To read the A/D conversion data, there is no need to use special instruction. The A/D
conversion data are automatically stored in the assigned input registers (XW registers).
For example, when the TC218 is allocated to XW000 to XW007, the A/D conversion data of
each channel is stored as follows.
XW000 : Channel 1 A/D conversion data
XW001 : Channel 2 A/D conversion data
XW002 : Channel 3 A/D conversion data
XW003 : Channel 4 A/D conversion data
XW004 : Channel 5 A/D conversion data
XW005 : Channel 6 A/D conversion data
XW006 : Channel 7 A/D conversion data
XW007 : Channel 8 A/D conversion data
Therefore, in the u s er program, you can use these XW registers directly for the analog data
processing.
The program shown below is an example of simple comparison with the channel 2 input data.
(Thermocouple type K setting)
By the above program, the ON/OFF status of the internal relays R0200 to R0203 are changed
as follows.
Status of the internal rel ay s
Temperature XW001 data R0200 R0201 R0202 R0203
More than 550 °C 11000 < XW001 ON ON OFF OFF
510 to 550 °C 10200 < XW 001 ≤ 11000 OFF ON OFF OFF
490 to 510 °C 9800 ≤ XW 001 ≤ 10200 OFF OFF OFF OFF
450 to 490 °C 9000 ≤ XW 001 < 9800 OFF OFF ON OFF
Less than 450 °C XW001 < 9000 OFF OFF ON ON
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