Epson LQ-1000 - Impact Printer, User Manual

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128
64
32
16
8
4
2
1
Figure
6-1.
Pin numbering system
To fire any one pin, you send its number. To fire more than one pin
at the same time, add up the numbers of the pins and send the sum to
the printer. With these labels for the pins, you fire the top pin by send-
ing 128. To fire the bottom pin, you send 1. If you want to fire only the
top and bottom pins, you simply add 128 and 1, then send
129.
By adding the appropriate label numbers together, you can fire any
combination of pins. Figure
6-2
shows three examples of how to calcu-
late the number that will fire a particular pattern of pins.
Figure 6-2. Calculations for pin patterns
With this numbering system, any combination of the eight pins
adds up to a decimal number between 0 and
255,
and no numbers are
duplicated.
Since there are
24
pins in each column, you must make a calculation
for each of the three sections in each column. As you can see, this
method of planning and printing dot graphics requires considerable
calculation. Because triple-density uses 180 columns per inch, printing
6-4