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6.4. External Trigger Modes
This camera has 6 external asynchronous trigger modes, which can be set by RS-232C commands.
1. Edge Pre-select Mode.TR=1 Pre-selected exposure. (SM=0, SM=1)
2. Pulse Width Control Mode. TR=2 Pulse width controlled exposure. (HC=0, HC=1)
3. Frame Delay read out mode. TR=3 PWC exposure read out by ext. VD. (HC=0, HC=1)
4. Long Time Exposure Mode. TR=4 Exposure is interval between ext. VD.
5. Start/stop Mode. TR=5 Exposure start by trigger and stop by ext. VD
6. Smearless Read out mode. TR=6 EPS Exp. after fast dump readout.(SM=0, SM=1)
The default accumulation is HD synchronously accumulation (HC=0). The accumulation starts at
the first HD after the trigger leading edge. Details are shown in fig.15.
In PWC mode (TR =2) and Frame Delay readout (TR=3), the accumulation mode HC can be set to
asynchronous accumulation (HC=1). The exposure will start immediately at the leading edge of
the trigger pulse without waiting for the HD. Fig. 16. below shows the details.
In Edge pre-select TR=1 and smearless TR=6, the shutter mode can be SM=0 or SM=1.
Smearless read out will reduce the smear caused by highlighted zones seen in images taken with
a short shutter speed. Before the accumulation can start, a fast dump read out is performed. It
takes 28H from trigger leading edge to start of accumulation.
Important notes on using trigger modes
• The HD synchronized accumulation starts at the first HD after the trigger leading edge.
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 A, which is 8 µsec.
• Do not input a new trigger before the previous video is read out. (WEN is high).
Fig. 14. Trigger/HD timing.
A=8
µ
sec
t
1
t
2
t
3
t
4
t
5
HD
Trigger
Xsub
Xsg
EEN
Accum
t
1
t
2
t
3
t
4
t
5
HD
Trigger
Xsub
Xsg
EEN
Accum
HD
Trigger
Xsub
Xsg
EEN
Accum
Note:
Xsg and Xsub are
internal signals in the
camera. They are shown
in the timing diagram
f
or better
understanding.
Fig. 15. Pulse Width H synchronous accumulation.
HD
Trigger
Xsub
Xsg
EEN
Accum
t
1
t
2
t
3
t
4
HD
Trigger
Xsub
Xsg
EEN
Accum
t
1
t
2
t
3
t
4
Fig. 16. Pulse Width H asynchronous accumulation.
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