PGL Programmer's Reference Manual

273

C Vertical Paper Motion

Introduction

There are three methods of advancing the print position with the IGP/PGL

which are explained in this appendix:

1. Using line feeds or form feeds;

2. Using the paper instruction (PI) line; or

3. Using the Electronic Vertical Format Unit (EVFU).

Paper Motion Using Line Feeds and Form Feeds

The most common method of advancing the print position with IGP/PGL is

through the use of line feeds and form feeds. A line feed moves the print

position down a distance determined by the current line spacing (lpi). In the

Normal mode, a form feed character advances the print position to the top of

the next page; in the Execute mode, a form feed advances the print position

to the top of the next

form

. Form length is determined by the CREATE

command.

Paper Motion Using the PI Line (Relative Line Slewing)

The method of moving the print position using the PI line results in vertical

slews of a specified number of lines relative to the current print position

(rather than slewing to a specific line). For this to occur, the following criteria

must be met:

1. The PI line must be enabled and set high; and

2. Data bit 5 must be 1 (set).

When a number of blank lines will be skipped on a form, (called “paper

slewing”) another method of paper motion may be used. The PI signal can be

detected by the IGP/PGL as the 8th data bit in a serial interface, or a separate

input line in a parallel interface. (Refer to the EN-PI/DIS-PI command and the

PION/PIOFF commands on page 78.) When the PI signal is used, bits 6 and 7

are interpreted as 0 values, and characters hex 10 through 1F are interpreted

as binary slew commands.