Avery Weigh-Tronix WP-233 Series, Руководство пользователя, Страница: 32 / 40

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The mechanism used in printer prints one line of dots
across at a time. This means that when it prints one
line of characters it has actually printed ten lines of
dots where the first eight lines make up the character
and the last two lines are blank for the space between
character lines. By using the CHR$(18) control code,
you can tell the printer which dots to print for one
whole dot line. Since there are 144 dots per line, you
must follow the CHR$(18) control code with 144 bits
of information. For every place there is a one in the
144 bit pattern you send, the printer will print a dot.
Rather than receive one bit at a time the printer
expects to receive the information eight bits at a time.
This means that after receiving a CHR$(18) the next
eighteen 8 bit characters it receives will be printed as
dots to form one dot line.
To figure out the dot pattern values to send after the
CHR$(18), you will need some grid paper. A large
sheet with 144 grid boxes across would be conve-
nient. If such a large sheet of paper is not available,
you could divide your pattern in half and work with 72
grid boxes across. Divide up your grid paper by
drawing a heavy line down every 8 boxes across.
Now fill in each box of the grid that you want to be
printed. Now do the following procedure to compute
the eighteen values which describe your desired bit
pattern.
Imagine placing the number sequence over each of
the first eight grid boxes.
Now add together all the numbers above the boxes
which are filled in or have a dot as in the example
above. In our example, we would have 2 + 16 + 32
which equals 50. The 50 becomes the first entry of a
data statement which would be followed by seven-
teen more numbers computed in the exact same
manner as the example.
Once you have the eighteen values in a data state-
ment, you need simply run a program which PRINTS
a CHR$(18) followed by the data value read from the
data statement. Don’t forget to end all of your Print
statements with semicolon. This will prevent carriage
returns CHR$(13) from being sent, which would
become part of the eighteen data values for which the
printer is waiting.
Dot Graphics
Code 18