Vinten Radamec HS-2010MED Pan & Tilt Head - Manual (Page 64)

HS-2010MED Maintenance And Repair
4-14 User Manual
Theory Of Operation
System
Refer to the Dolly Wiring diagram at the end of this chapter for a block diagram
of the HS-2010MED electronics. Schematics and component locators can also
be found at the end of this chapter.
Power
All of the power for the head is derived from the +30V DC power bus from the
SP-2000 pedestal, the SE-1000 elevation unit, or directly from the rack mounted
power supply. The serial data to control the head is carried through the same
cable.
Each board locally regulates its own operating voltages from the +30V supply.
Usually these on-board supplies include a 24V supply for relays, lamps, and
solenoids, +15V and -15V for analog circuitry, and +5V for digital circuitry. The
+5V and -15V supplies are switching supplies.
The head should always be switched off before disconnecting cables. The head
is designed to operate at voltages as high as 40V, but at voltages higher than
approximately 45V, the 4 Channel Servo Board will clamp the voltage to mini-
mize damage and will possibly blow on-board fuses in the process.
Data Bus
The data bus is a 4-wire uni-directional 9600-baud RS-422 signal originating at
the controller, looping through the power supply and pedestal (if installed) and
up to the head. With RS-422, both sides of the data leads are electrical mirror
images of each other. Each should look like a TTL signal. A fault condition is
indicated by identical signal phase on both lines, or one line stuck. Some types
of problems with the data areas of the boards can block data from reaching other
boards downstream. A symptom of missing data can be a useful troubleshooting
aid. The on-board “happy light” LEDs are a valuable aid when troubleshooting
data path problems.
The data frames are sent to the pedestal at 25ms intervals. Within each frame are
command bytes for each servo axis, which each servo board picks off as appro-
priate. Each servo board has an address, as determined by the on-board jumper
(J1) and this allows 4-channel boards complete with ROMs to be interchange-
able.
4 Channel Servo Board
The 4 Channel Servo Board in the head provides control of pan and tilt of the
head and zoom and focus on the lens. The board contains a microprocessor and
related circuitry, local power supply regulation and data interconnections.
This board is electrically identical to the 4 Channel Servo Boards in the SP-
2000, the Shunt jumper (J1) in the lower right corner must be changed if you