ARC130S
SECTION 3
Installation
ARC130S 060801 Version 1 Issue 1
3.7
GPI Overview
The GPO provides contact closure tally outputs
that can be used to turn on lamps etc.
GPO 0 tracks GPI 0 so if the display memory that
GPI 0 recalls is active then GPO 0 will close.
Similarly, GPO 1 tracks GPI 1 etc.
This functions even if the GPI inputs have been
assigned different recall memories and if the
memory was recalled via a front panel button
rather than via the GPI.
So, if GPI 3 recalls AUTO, then whenever AUTO is
selected GPO 3 will be closed.
In GPI binary mode, the four LSB’s (GPO 0 to
GPO 3) GPI contacts indicate the binary GPI
memory in use. The four MSB’s (GPO 4 to GPO 7)
contacts are closed if a GPI binary memory is
being used; otherwise they are open.
If a non-binary GPI memory is being used all 8
contacts will be open.
GPI interface Delay
The GPI interface on the ARC130S has a delay
that matches the video processing delay through
the ARC.
This means that if a given input-video field is
desired to produce the first output-field built with a
new aspect ratio conversion; the GPI contacts that
recall that new aspect ratio conversion should be
closed during the field when that video field is
present at the ARC130S input.
Ideally, the contact should be closed a few lines
after the vertical sync group of the reference video,
and, should remain closed for at least one field
period.
