Guardian Programmer's Guide

Communicating With Printers
Guardian Programmer’s Guide — 421922-014
11 - 21
Controlling Forms Movement
Controlling Forms Movement
Vertical positioning is done on the 5515/5516/5518 printers by looking up values in the
vertical form control (VFC) table in printer memory. You can do this in two ways:
•
Use the CONTROL procedure with operation 1
•
Use an escape sequence
Using CONTROL Operation 1 to Position the Paper
To vertically position the paper using CONTROL operation 1, you need to supply the
function to be performed. This function is supplied as a parameter to CONTROL
operation 1. The I/O process converts the parameter into an escape sequence that
accesses the VFC table.
The following example positions the paper to the next one-half page:
LITERAL POSITION = 1,
NEXT^HALF^PAGE = 5;
.
.
CALL CONTROL(PRINTER^NUM,
POSITION,
NEXT^HALF^PAGE);
IF <> THEN ...
Refer to the description of the CONTROL procedure in the Guardian Procedure Calls
Reference Manual for a complete list of vertical positioning options for printers with
subtype 7.
Using an Escape Sequence to Position the Paper
To position the paper using an escape sequence, you use an escape sequence with a
format like this:
channel-num indicates a channel number in the range 0 through 16 in the VFC table.
The VFC table contains one row for each line that can be printed on a page. Each row
is made up of 17 columns called VFC channels.
Each row/column location in the VFC table contains either a 0 or a 1. A 0 indicates
that the line cannot be accessed when the channel is selected. A 1 indicates that the
line can be accessed when the channel is selected.
Table 11-4 shows part of the default VFC table. The printer software automatically
calculates the default VFC table according to the number of lines on the logical page.
Escape sequence to position the paper:
esc&lchannel-numV