Miranda Imagestore 2, Руководство пользователя

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Imagestore User Manual Easysound Audio
Miranda Technologies Ltd Page 143
Cross-connecting GPIs
Caution
You must consider the full implications of cross wiring very carefully before
you cross connect GPIs. It should never be possible for one of the lines to be
driven high whilst a line cross-connected to it is being clamped low.
The SDI GPI (image) and AES GPI (audio) control ports are not internally
connected and operate independently. However, should there be a
requirement for joint operations such as the cross fading between both image
and audio, it is possible to cross wire GPI ports externally. Since the GPI
ports feature GPI status outputs you can use the GPI
out port of one control
to trigger the GPI in port of the other. This concept is also suitable for
triggering the functions of other non-Miranda Technologies Ltd equipment.
Connection of external analogue faders
Analogue faders may be used to control fades and mixes. A resistive
potentiometer of at least 20K
Ω
should have its fixed terminals connected
between pin 7 (Analogue Fader V+) and pin 15 (Analogue Fader ground).
The variable output of the pot should connect to the appropriate fader input
pin.
Screened cable should be used to connect the fader to the Imagestore and the
screen of the cable should
only be connected to ground at the Imagestore end
of the cable to avoid earth loops , and to restrict extraneous signal levels to
less than 1 mV.
Input to GPI
GPI ports 1 to 7 can be used as either input or output ports, but GPI ports 8
and 9 are only available as inputs. Where a GPI port is used for input, the
command line is considered
ON when low (achieved by grounding the input)
and OFF when allowed to float to the +V supply. Input triggering is
achieved by the negative transition to 0v for 'ON' and by the positive
transition to +V for
OFF .