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If a valid 3D synchronization signal is fed from the projector to the unit, it starts modulating the incoming light and normal 3D viewing is
possible. Validity of the signal is determined by f
smin
(3D Sync Low Threshold Frequency) and f
smax
(3D Sync High Threshold Frequency). See
macros descriptions in section
Network Mode Control Source
and section
Using the Configuration Utility
.
In 3D mode the SYNC/3D MODE LED state depends on the presence of a valid 3D synchronization signal coming from the projector. If a valid
3D sync is detected, the LED is ON. If the signal is not present or is invalid, the LED is OFF.
Note: When “frame sync” mode control source is selected, absence of a valid 3D synchronization signal automatically sets the mode to 2D.
See the
Mode Control Sources
section of this manual for more information.
While in 3D mode, the unit continuously scans for conditions to transition to 2D mode. The conditions depend on which mode control source
is selected - refer to section
Mode Control Sources
.
Mode Control Sources
The XPAND Trinity 3D Superlight Polarizer has three ways of determining whether it should operate in 2D or 3D mode:
(A) Detecting a valid 3D synchronization signal coming from the projector -> “Frame Sync mode control source”
(B) Listening for a 3D or 2D command macro on the LAN -> “Network mode control source”
(C) Triggering on a dedicated GPIO line of the GPIO connector -> “GPIO mode control source”
Which one of the three mode control sources is active can be set using the PC-based configuration utility (see the
Using the Configuration
Utility
->
Device Mode Control Settings
section, parameter
Mode Control Source
) or by sending a dedicated string macro command over
the network from a projector or digital cinema server (see the “modctrls” command in section
Network Mode Control Source
). By default
the “Frame Sync” mode control source is selected.
Frame Sync Mode Control Source
The default way of determining whether the unit must begin operating in 3D mode is to monitor the 3D synchronization signal line coming
from the projector for the presence of a valid synchronization signal. This signal comes into the Trinity Polarizer through its GPIO connector.
If a valid signal is detected, the unit transitions to 3D mode and stays there for as long as the signal is present.
The 3D synchronization signal is a square wave. The unit determines whether a signal is valid or not by measuring its frequency. By default
all signals with a frequency between 35 Hz and 150 Hz are considered valid. However, these limits can be modified through the unit’s
PC-based configuration utility. For more information see section
Using the Configuration Utility
->
Device Mode Control Settings
,
parameters
3D Sync Low Threshold Frequency
and
3D Sync High Threshold Frequency
.
GPIO Mode Control Source
If the unit is set for GPIO Mode control source, it then supports control over one GPIO line which is typically connected to one of the projec-
tor’s or digital cinema server’s GPIO lines.
By default an externally applied open loop / open circuit between pins 3 and 8 sets 2D mode. Close circuit on those same pins sets 3D mode.
Polarity can be inverted by using the PC-based configuration utility (see section
Using the Configuration Utility
->
Device Mode Control
Settings
, parameter
GPIO Signal Polarity
) or by sending a dedicated command macro from the projector or the digital cinema server (see
the “gpiopol” command in section
Network Mode Control Source
).
An optically isolated open-collector or open drain GPIO control line needs to be connected between pins 8 and 3 to avoid
damage to the unit and/or projector - see below schematics. Projectors and servers are typically equipped with such outputs
so only a suitable passive cable is required.
Alternatively CMOS levels with a 3.3 V supply can be used with pin 8 connected
to GND. However optically isolated lines are preferred.
