Vertical Tab; 4.7.4 Wertical Format Unit; Form Feed And Vertical Tab Timing - Centronics 101AL Technical Manual

For as long as PMSOL is active, the printer remains in a busy con-
dition.
FORM FEED OR
VERTICAL TAB
(SEE SECTIONS
4.7.2 & 4.7.3)
PMSOL
FFH OR VTH ( C L
DLYLF \ece 90 ns——]___
pusy —_] L__
0-10 pS al
ACKNLG | |
2.5-5.0 us|
Figure 4-10. FORM FEED AND VERTICAL TAB. TIMING
4.7.4 WERTICAL FORMAT UNIT
The vertical format unit (VFU) consists of a standard 8-channel
paper tape reader, located on the upper left side of the printer. Move-
ment of the paper tape in the VFU is caused by direct mechanical linkage
to the gear train that drives the paper feed tractors. As a result, each
line feed advances the paper by one line and the tape by one sprocket hole.
Each form feed function advances paper until the next hole is de-
tected in channel 7 of the paper tape. Similarly, each vertical tab function
advances paper until the next hole is sensed in channel 5 of the paper tape.
A schematic of the VFU amplifier is shown in Figure 4-11.
4-28