User's Manual

Documentation Number 232OPSDA1397 Manual 25
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Step 1 - Constructing the command string:
Command$ = “!0RD”
Step 2 - Transmitting the command string:
Print #1, Command$
Step 3 - Receiving the data:
Reply$ = INPUT$ (1, #1)
Step 4 - Manipulating the data:
states = ASC(Reply$)
Step 5 - Determining an I/O’s status
status = states AND mask
By “ANDing” the value of states with the appropriate mask of an I/O
line, the status of can be determined. If status is equal to zero then
the I/O line is LOW. If status is not equal to zero then the I/O line is
HIGH. Table 5.1 shows the mask values for each I/O.
Table 5.1 - Digital I/O Mask Values
Step 6 - Repeat Step 5 until the status of each I/O has been
determined.
Example 5.2 - Determining the status of Digital Input #0 of the
module.
mask = &H8
Command$ = “!0RD”
Print #1, Command$
Reply$ = INPUT$ (1, #1)
states = ASC (Reply$)
status = states AND mask
If status is equal to zero than Digital Input #0 is LOW. If status is not
equal to zero than Digital Input #0 is HIGH.
Mask Values
I/O Line Hexadecimal Decimal
Digital Output #0 1H 1
Digital Input #0 8H 8