Vinten Radamec HS-2010MED Pan & Tilt Head - Manual (Page 67)

HS-2010MED Maintenance And Repair
User Manual 4-17
when other motors are activated. This board decouples the grounds by receiving
an ungrounded differential signal from the 4 Channel Board. Up to 3 volts of
ground offset can be corrected.
Jumpers (J3 for zoom and J4 for focus) are provided on the board to reverse the
direction sense of the lens if necessary to match the AutoCam convention.
Another function of the Native board is to match the full range travel of the lens
elements to the +10V/-10V range of the AutoCam demand voltage. For exam-
ple, the lens might only require 0V/+5V, or -5V/+5V for full range travel. A
wide range of lens voltages between 4V and 24V full scale, with an offset of up
to 5V of either polarity can be accommodated using the pots on the board.
This board also allows automatic changeover from local lens control to Auto-
Cam lens control. This changeover is activated by a 5V signal from the tilt lock-
ing switch in the head.
The board is normally factory set for a centered +2V/-2V output, which should
allow the zoom and focus controls to operate over a limited range with virtually
any lens. Refer to Chapter 3 for the calibration procedure.
Brushless Motors
Two brushless motors and switching drivers are used in the HS2010MED head -
one for pan and one for tilt. One of the advantages of brushless motors is that
they are quieter because they avoid the screechy high-frequency sound emitted
by the brushes of conventional DC brush motors and tachometers. Tachometers
are eliminated completely because the velocity information is derived from the
Hall effect encoders. Brushless motors are far more reliable and are expected to
last the life of the product. In addition, the switching drivers are very efficient,
so power consumption is reduced and battery operating time is extended.
Motor servicing is limited to verifying the integrity of the two quadrature signals
coming from the encoder on the motor.
Motor Drive Amplifiers
The Motor Drive Amplifiers amplify the demand signal from the 4 Channel
Board to generate a torque-producing current that drives the motor. In addition,
they electronically commutate the brushless motor by processing the TTL phas-
ing signals from the hall encoders. There are no adjustments on the Motor Drive
Amplifiers. Each amplifier does have pluggable, factory selected current-setting
resistors.
The two Motor Drive Amplifiers for pan and tilt are not serviceable at the com-
ponent level in the field. However, they can be swapped with other 30V Motor
Drive Amplifiers to isolate a fault. 30V Motor Drive Amplifiers are also used for
steer and drive in the SP-2000 Pedestal. Note that the Motor Drive Amplifier for
column elevation is a 60V amplifier which cannot be swapped for troubleshoot-
ing.
Contact Vinten to arrange a board exchange if necessary. If replacement amplifi-
ers are installed, the resistor values in the pluggable resistor packs must be