8mm Forum: GS1200 : ESS mode Question

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Posted by Phil Murat (Member # 5148) on February 06, 2018, 11:49 AM:

Hello GS1200 Fan's,

Once setted on ESS mode , the machine starts normaly when it get a Pulse signal.

When in stand by,means no sync pulse sent, the rear arm take-up spindle spins alone .....

Is it a normal situation ?

If yes, I don't see the needs for the rear spindle to run during stand by mode...

All informations welcome.
Thanks in advance

[ February 06, 2018, 11:27 PM: Message edited by: Phil Murat ]

Posted by Renzo Dal Bo (Member # 5688) on February 06, 2018, 01:17 PM:

In stand by mode, the flywheel is not maintained in motion, as it happens in stop mode. So that the start of the projection is a tricky moment, full of stress for the film.
Maintaining the rear spindle in motion reduces the inertia at the start, and the slipping of the first ESS pulse signal with the current frame projected.
Furthermore the ESS control sistem acts only on the main motor speed, all the remain services have to be ready to work before the start.

[ February 06, 2018, 03:52 PM: Message edited by: Renzo Dal Bo ]

Posted by Phil Murat (Member # 5148) on February 06, 2018, 11:31 PM:

Thanks Renzo, This is clarifying this particular point.

I understand too there is a normal time lag for approx three frames at start (ESS Mode). This is to prevent from "unwanted" start in case of wrong pulse coming into.

Do you confirm ?

[ February 07, 2018, 05:55 AM: Message edited by: Phil Murat ]

Posted by Renzo Dal Bo (Member # 5688) on February 07, 2018, 08:39 AM:

Three frames correspond more or less to 1/10 of a second. I think this is the time the projector takes to accelerate from 0 up to reach 24 fps.

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