B&B Electronics RS-232 Digital I/O Module 232SDD16 Manual de usuario descargar pdf (Pagina 13)

232SDD16-1005 Manual 21

B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 -- FAX (815) 433-5104

Chapter 5 - Software

This chapter will be divided into two sections. The first section

covers programming techniques for constructing a command string,

receiving data and manipulating data in QuickBASIC. The second

section discusses how to install and run the demonstration program

on an IBM PC or compatible.

Programming Techniques

This section shows steps and examples of programming the

232SDD16 in QuickBasic. If you are programming in another

language, this section can be helpful as a guideline for programming

the 232SDD16.

Read I/O States Command

Step 1 - Constructing the command string:

Cmnd$ = "!0RD"

Step 2 - Transmitting the command string:

PRINT #1, Cmnd$;

Step 3 - Receiving the data:

MSIO$ = INPUT$(1,#1)

LSIO$ = INPUT$(1,#1)

Step 4 - Manipulating the data:

MSIO = ASC(MSIO$)

LSIO = ASC(LSIO$)

Step 5 - Determining an I/O's status:

MSstatus = MSIO AND mask

LSstatus = LSIO AND mask

By "ANDing" the value of MSIO or LSIO with the appropriate

mask of an I/O line, the status of the I/O line can be determined.

If the status is equal to zero the I/O line is LOW. If the status is

not equal to zero the I/O line is HIGH. 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.

22 232SDD16-1005 Manual

B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 -- FAX (815) 433-5104

Example 5.1 - Determining the status of I/O lines #2 & #10

mask = &H4

Cmnd$ = "!0RD"

PRINT #1, Cmnd$;

MSIO$ = INPUT$(1,#1)

LSIO$ = INPUT$(1,#1)

MSIO = ASC(MSIO$)

LSIO = ASC(LSIO$)

MSstatus = MSIO AND mask

LSstatus = LSIO AND mask

If LSstatus equals zero then I/O line #2 is LOW. If LSstatus is not

equal to zero then I/O line #2 is HIGH. If MSstatus equals zero then

I/O line #10 is LOW. If MSstatus is not equal to zero then I/O line

#10 is HIGH.

Read Configuration Command

Step 1 - Constructing the command string:

Cmnd$ = "!0RC"

Step 2 - Transmitting the command string:

PRINT #1, Cmnd$;

Step 3 - Receiving the data:

MSdefs$ = INPUT$(1,#1)

LSdefs$ = INPUT$(1,#1)

MSpups$ = INPUT$(1,#1)

LSpups$ = INPUT$(1,#1)

Step 4 - Manipulating the data:

MSdefs = ASC(MSdefs$)

LSdefs = ASC(LSdefs$)

MSpups = ASC(MSpups$)

LSpups = ASC(LSpups$)

Table 5.1 - Digital I/O Mask Values

Mask Values

I/O Line # Hexadecimal Decimal

0 & 8 1H 1

1 & 9 2H 2

2 & 10 4H 4

3 & 11 8H 8

4 & 12 10H 16

5 & 13 20H 32

6 & 14 40H 64

7 & 15 80H 128

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 26 27

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