External Trigger Modes, Edge Pre-select Mode.TR=1

CV-A11

6.4. External Trigger Modes

This camera has 6 external asynchronous trigger modes, which can be set by RS-232C commands.

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.

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 ∝sec.

•Do not input a new trigger before the previous video is read out. (WEN is high).

A=8 µsec

Fig. 14. Trigger/HD timing.

Trigger

Accum

Xsub

Xsg

EEN

Note:

Xsg and Xsub are internal signals in the camera. They are shown in the timing diagram for better understanding.

Fig. 15. Pulse Width H synchronous accumulation.