Crystal Vision
Hardware installation
2.4 General Purpose Interface (GPI)
Each frame slot has up to six connections ‘a-f’ for GPI control and monitoring. These
connections are available at the rear of the frame on the 26-way D-Type remote connectors.
GPI
Low (<1V)
High (+5V)
0
‘a’ Recall preset bit 1
See following table for user preset control
1
‘b’
Recall preset bit 2
2
‘c’
Recall preset bit 4
3
‘d’
Recall preset bit 8
4
‘e’
Video missing
Selected Alarms
asserted
No alarm
5
‘f’
Output channel
silence
(delayed alarm)
Selected Alarms
asserted after set delay
No alarm
As supplied, each GPI output has a 270Ω resistor in series with its output. This allows for an
external LED to be driven, connected to a DC voltage of +5V.
Each General Purpose Input (GPI) is fitted with a 6800Ω resistor connected to the internal
+5V.
The 16 user preset configurations can be recalled using binary notation.
GPI
Bit 4
Bit 3
Bit 2
Bit 1
Preset
1
0
0
0
0
2
0
0
0
1
3
0
0
1
0
4
0
0
1
1
5
0
1
0
0
6
0
1
0
1
7
0
1
1
0
8
0
1
1
1
9
1
0
0
0
10
1
0
0
1
11
1
0
1
0
12
1
0
1
1
13
1
1
0
0
14
1
1
0
1
15
1
1
1
0
16
1
1
1
1
TANDEM HD-21 User Manual R1.6
13
12/11/2012
