User's Manual

16
The three channel Motor Driver (MDR2) is responsible for driving the motors, providing
control signals to the camera, and transferring camera operating data to the wireless
network through the transceiver module.
The MDR2 uses a lens calibration sequence to determine the mechanical limits of the zoom,
focus, and iris rings of the lens. This sequence is initiated whenever the Reset button on the
MDR is pressed, or whenever a motor is connected to the Motor Driver. Lens calibration
allows for precise, repeatable marks and also prevents accidental damage to the lens or
Digital Motor. An internal memory stores the positions of a calibrated lens for 12 hours
without external power.
To further protect the lens and driver electronics, the motors are electronically torque
limited and electronic motor stall protection is provided. In addition, self-resetting thermal
fuses protect all three channels. This insures that even in the event of improper calibration,
the motors will remain protected from overheating.
The Direction Reversing and three-level motor torque switches are located adjacent to each
of the three motor connectors.
Camera control signals are provided at the “Camera" receptacle of the MDR2. Signals are
available both for run/stop as well as for controlling the camera speed and shutter angle.
This receptacle also accepts real-time speed, shutter angle and run/stop status data from
the camera and transmits it via the Microwave Link to the HU3 as well as all the other
wireless units set to the same channel. In addition, the camera receptacle provides the
signals required for VTR start and internal zoom drive for Sony cameras as well as Canon
and Fujinon video style lenses with integral zoom drives.
The Microwave Transceiver is located in the lid of the MDR2. It provides wireless bi-
directional communication between the MDR2, Hand Unit, F/X unit and other clients in the
wireless network. In addition, it contains a voltage booster enabling MDR operation over an
input voltage range from 11 to 30 volts.
The wireless channels are selected by turning the two channel switches located on the
MDR2 top cover. There are 30 channels numbered 0 – 29. Channels above 29 repeat the
sequence, so that channel 30 is the same as channel 0, and so on.
A slide switch on the cover selects between Cable and Radio operation.
The software controlling the MDR-2 is updated through the “Serial” receptacle and the
Serial-PC cable that connects the MDR to the serial “D” connector of a PC. Software updates
are available either as a CD or download from our web site:
www.prestoncinema.com.
MDR2: Torque and Direction Switches Channel Selector Switches