Functions and Operations, Input/Output of HD/VD Signal

CV-M50

6. Functions and Operations

6.1. Input/Output of HD/VD Signal

6.1.1. Input of External HD/VD Signal

As factory setting the camera can be synchronized by external HD/VD signals. The signal level must be 4.0V p-p +/- 2.0V at the input with the 75 Ohm termination ON. To change to non-terminated input, see instructions in “7. Mode Setting”.

If no ext. HD is connected, the camera will switch to the internal X-tal controlled HD. If no ext. VD is connected, the camera will continue with its internal VD.

6.1.2. Output of Internal HD/VD Signal

The internal HD/VD output is 4.0V p-p from a 75 Ohm source.

To select this mode, see instructions in “7. Mode Setting”.

6.2. Normal Shutter Mode

When trigger select SW1-4 is OFF, the camera is in normal mode. The SW1-1, SW1-2 and SW1-3 are for selecting the shutter speed. The range is from OFF to 1/10,000 second in 8 steps. The camera is running continuously with an exposure as the selected shutter time.

The shutter time setting is shown in “7.1.3. Table for Shutter Time”.

6.3. External Trigger Mode

External trigger mode of CV-M50 allows 4 different driving modes, as follow.

1Edge pre-select mode. (Asynchronous reset and exposure start by an ext. trigger)

2Pulse width control mode. (Exposure control by the low period of the ext. trigger)

3Start/Stop trigger mode. (Exposure start by the ext. trigger and end by the ext. VD signal)

4Long time exposure mode. (Exposure control by the interval of the ext. VD signal)

The trigger input is AC coupled, so there is a maximum pulse width for the trigger pulse about 60 msec. The signal level must be 4.0V p-p +/- 2.0V on the input with the 75 Ohm termination ON. To change to non-terminated input, see instructions in “7. Mode Setting”.

The following describes the details of each trigger mode.

6.3.1. Edge Pre-select Mode

The edge pre-select mode operation will only work in non-interlaced and field accumulation mode. The CV-M50 starts the exposure (= accumulation of photoelectric charge) at the first HD pulse after the falling edge of the ext. trigger pulse. The exposure ends after the time set by the 3 shutter switches SW1-1 to SW1-3. The range is 8 steps from OFF (1/60 or 1/50) to 1/10,000 second.

In this mode, the EEN (Exposure ENable) pulse and WEN (Write ENable) pulses are generated and output from the camera. The EEN pulse indicates the exposure time and can be used to control the illumination such as strobe light. The EEN pulse is output from pin 2 of the 6-pin multi connector. The signal level is 4.0 Vp-p from a 75 Ohm source.

The WEN pulse indicates the time period of the effective video signal output, and is useful for the timing and interfacing of external devices such as frame grabbers. The WEN pulse is output from pin 6 of the 6- pin multi connector. The signal level is 4.0 Vp-p from a 75 Ohm source.

The video must be read out before a new trigger can be applied. The interval between trigger pulses must be longer than the time for 1 field + the shutter time. It is the limit for the field rate.

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