Sync signal from Alexa (and Alexa 65)

General discussion
Post Reply
stuetr
Posts: 2
Joined: Thu Jun 16, 2016 5:02 pm

I'm looking at integrating a custom (strobe) lighting solution with the Alexa and Alexa 65. To do this I need to a sync signal from the camera. Ideally this would be a square wave that goes hi/low when the shutter opens and then goes the other way when the shutter closes. Can anyone tell me:

- which port on the Alexa provides this?
- what type of cable(s) there are that plug into this port (ideally looking for a BNC connection on the non-camera end)
- what type of sync signal is available (voltage, behaviour etc.)

Kind Regards,

Stu
DavidZucker
Posts: 3
Joined: Mon Jun 20, 2016 7:30 pm

Hello Stu,

The RS Output Signal is probably the most commonly understood external signalling of the cameras shutter. In the cameras ‘Run‘ state, it pulses between 9V and 5V. The Duty Cycle of the Period is proportional to integration time.
High (9V) start of integration
Low (5V) start of non-integration
N.B. The RS output only delivers a shutter signal when the camera is recording.

The latest FW release of the Alexa65 has a lovely new feature built into it.
On the front of the Alexa65, there is an "ACC" Output. On this output, there is a 3.3V TTL signal that goes high during integration time and down to 0V during non-integration time.
This feature is only available with Alexa65 SUP1.0:35300 or above.
Unlike the RS output, when the above mentioned signal is activated via the GUI (Menu -> Sensor -> Shutter Pulse on ACC OUT: On), this new output from the “ACC” port will always be running constantly - even when not recording.

Your local ARRI Rental house will be able to supply you with a cable to get this 3.3V TTL signal out of the ACC port.

All the best,
David
DavidZucker
Posts: 3
Joined: Mon Jun 20, 2016 7:30 pm

Following up on this topic:
With SUP1.1 for the Alexa 65, the above mentioned TTL shutter pulse signal functionality has been extended. The TTL pulse can now be inverted, as well as allowing the user to add a delay of up to 50ms with an accuracy of 100 μs (0.1ms) via the cameras GUI.
This added functionality provides the user with a useful tool to trigger external systems with the ability to manipulate the timing.
See attached GUI grab.
You do not have the required permissions to view the files attached to this post.
richard700
Posts: 1
Joined: Thu Feb 16, 2017 11:45 pm

"The RS Output Signal is probably the most commonly understood external signalling of the cameras shutter. In the cameras ‘Run‘ state, it pulses between 9V and 5V. The Duty Cycle of the Period is proportional to integration time.
High (9V) start of integration
Low (5V) start of non-integration
N.B. The RS output only delivers a shutter signal when the camera is recording."

Can you confirm the pin numbers for this output on the RS connector?
Thanks
Post Reply