External Trigger Modes - JAI CV-A50 Operation Manual

6.4. External Trigger Modes

This camera has 5 external asynchronous trigger modes, which can be set by RS-232C commands.
1. Edge Pre-select Mode.TR=1
2. Pulse Width Control Mode. TR=2
3. Frame Delay read out mode. TR=3
4. Long Time Exposure Mode. TR=4
5. Start/stop Mode. TR=5
An external trigger pulse initiates the capture (input on pin 11 of the 12-pin Hirose connector or
pin 5 of the 6-pin Hirose). The leading edge of the trigger pulse initiates the exposure (this is a
falling edge if factory default) and the duration of the pulse governs the exposure
(accumulation) time. If the polarity of this pulse is reversed, the camera can be configured to
correct for it.
The duration of the external trigger pulse must be greater than 1H. It is recommended to make
this longer, typically 9H.
Important notes on using trigger
The accumulation is HD synchronously accumulation. The accumulation starts at the first HD
after the trigger leading edge. Shown in fig. 15. To avoid the <1H jitter caused by this delay,
synchronize the external trigger to HD as shown in fig. 14. The trigger level translations should
be placed inside the time A, which is 8 µseconds.
Do not input a new trigger before the previous video is read out. (WEN is high).
HD HD
HD
Trigger Trigger Trigger
Accum Accum Accum
Xsub Xsub
Xsub
Xsg Xsg Xsg
EEN EEN EEN
CV-A50 / CV-A60
modes:-
Fig. 14. Trigger/HD timing.
t t
t t t t
1 2 3 3
1 2
Fig. 15. Pulse Width H synchronous accumulation.
Fig. 16. Ext. HD and ext. VD phase conditions.
Pre-selected exposure. (SM=0, SM=1)
Pulse width controlled exposure.
PWC exposure read out by ext. VD.
Exposure is interval between ext. VD.
Exposure start by trigger and stop by ext. VD
t t t
t
4 4 5 5
Note: Xsg and Xsub are
internal signals in the
camera. They are shown in
the timing diagram for better
understanding.
- 11 -
A=8 µse c
A=8µsec