B&B Electronics RS-485 Digital I/O Module 485SDD16 - Manual (Page 14)

485SDD16-1005 Manual 23
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Step 3 - Receiving the data:
MSdefs$ = INPUT$(1,#1)
LSdefs$ = INPUT$(1,#1)
MSpups$ = INPUT$(1,#1)
LSpups$ = INPUT$(1,#1)
Maddr$ = INPUT$(1,#1)
Mtdly$ = INPUT$(1,#1)
Step 4 - Manipulating the data:
MSdefs = ASC(MSdefs$)
LSdefs = ASC(LSdefs$)
MSpups = ASC(MSpups$)
LSpups = ASC(LSpups$)
Maddr = ASC(Maddr$)
Mtdly = ASC(Mtdly$)
Step 5 - Determining the I/O line definitions:
MSdefs = MSdefs AND mask
LSdefs = LSdefs AND mask
By "ANDing" the value of MSdefs or LSdefs with the appropriate
mask of an I/O line, the I/O line definition can be determined. If
the status is equal to zero the I/O line is an INPUT. If the status is
not equal to zero the I/O line is an OUTPUT. Table 5.1 shows the
mask values for each I/O line.
Step 6 - Repeat Step 5 until the status of each I/O line has been
determined.
Step 7 - Determining an OUTPUT's Power-up state:
MSpups = MSpups AND mask
LSpups = LSpups AND mask
By "ANDing" the value of MSpups or LSpups with the appropriate
mask of an Output line, the Output line definition can be
determined. If the status is equal to zero the Output power-up
state will be LOW. If the status is not equal to zero the Output
power-up state will be HIGH. Table 5.1 shows the mask values
for each I/O line.
Step 8 - Repeat Step 7 until the power-up state of each Output line
has been determined.
Example 5.2 - Determining the definition and power-up state of I/O
lines #2 & #10 of module #5.
24 485SDD16-1005 Manual
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PH (815) 433-5100 -- FAX (815) 433-5104
Maddr = 5
mask = &H4
Cmnd$ = "!" + CHR$(Maddr) + "RC"
PRINT #1, Cmnd$;
MSdefs$ = INPUT$(1,#1)
LSdefs$ = INPUT$(1,#1)
MSpups$ = INPUT$(1,#1)
LSpups$ = INPUT$(1,#1)
Maddr$ = INPUT$(1,#1)
Mtdly$ = INPUT$(1,#1)
MSdefs = ASC(MSdefs$)
LSdefs = ASC(LSdefs$)
MSpups = ASC(MSpups$)
LSpups = ASC(LSpups$)
Maddr = ASC(Maddr$)
Mtdly = ASC(Mtdly$)
MSdefs = MSdefs AND mask
LSdefs = LSdefs AND mask
MSpups = MSpups AND mask
LSpups = LSpups AND mask
If LSdefs equals zero then I/O line #2 is an INPUT and if not equal
to zero then I/O line #2 is an OUTPUT. If MSdefs equals zero then
I/O line #10 is an INPUT and if not equal to zero then I/O line #10 is
an OUTPUT. If LSpups equals zero then Output line #2's power-up
state is LOW and if not equal to zero then Output line #2's power-up
state is HIGH. If MSpups equals zero then Output line #10's power-
up state is LOW and if not equal to zero then Output line #10's
power-up state is HIGH. Maddr is the decimal address of the
module. Mtdly is the decimal number of character times that make
up the turn-around delay.
Set Output States Command
The Set Output States command is used to set the states of any
I/O line that is defined as an output. This command requires two
data bytes. Refer to this command in Chapter 3 for more
information.
Step 1a - Construct the command string:
Set appropriate outputs HIGH
MSstates = MSstates OR mask
LSstates = LSstates OR mask
By "ORing" the current states with the appropriate mask of a
digital output line, the output's bit will be set to a "1" (HIGH).