Troglotech T812 Manuel d'instructions
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 1
WORKSHOP MANUAL — T812 Pan & Tilt Camera
Troglotech Ltd Phone +44( )173 71124
Unit 1, 3 Penns Road Phone +44( )173 71124
Petersfield Fax +44 ( )173 71124
Hampshire Email info@troglotech.com
GU32 2EW Web www.troglotech.com
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 2
T812 CAMERA - OVERVIEW
T812 Pan and Tilt Camera
The T812 camera is designed for simple maintenance and fault finding, each PCB
and section has a distinct function which can operate independently. For instance,
the Rod Adaptor, when connected to a supply, will provide 5V, 15.6V and IIC
messages even if not connected to the Camera Head. If the Pan mechanism is
removed from the Camera Head, the camera will still level the Rotate assembly.
The Camera Head can be swapped between Rod Adaptors without the need for
re-calibration—the calibration data is stored on the Rotate PCB (812/ 4).
Start-up Routine
When the camera is connected to a system or a bench supply and power is
applied it will go through a start-up routine:
Once the processor (812/22) receives power from the power supply PCB (812/21)
it will wait for 2 seconds and then command the Counter-Rotate and Pan motors to
operate. As the Pan mechanism has a large seal which can provide a lot of friction
when the head is cold, the pan motor is provided with a ramping current and the
pan position is continually sampled to see if the mechanism is turning. The current
is increased until the Pan mechanism starts turning—if it fails to turn after 15
seconds the motor direction is reversed momentarily to break the seal friction.
Once the Pan mechanism is turning, the speed is adjusted (by altering the current
to the pan motor via PWM control) until the Pan mechanism realises a linear
speed of 36 degrees per 13 seconds.
During this period, the processor will continually monitor the Pan and Counter
Rotate sensors until each sensor detects a large value change. At this point the
processor saves the maximum and minimum values. The processor commands
the Pan and Counter Rotate motors to stop once these values are stored and the
Pan Speed is within limits. If either motor keeps running this usually indicates the
lack of the respective sensor signal. Once completed the camera will start the
‘centralise’ routine where the Counter-Rotate, Pan, and Rotate mechanisms will
servo to a straight-ahead and upright position.
Once centred, the T812 will accept data commands from the T8 4 and will start
transmitting data - both data streams are sent and received via signals multiplexed
on the Video+ve conductor. The T8 4 does not need to receive data from the
T812 to send out commands - and the T812 does not need to receive data to
transmit data back. Currently, the data from the T812 is not used by the T8 4.
More information on the data can be found in the “TTDS - Troglotech Data
System.pdf” document.
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 3
T812 CAMERA - OVERVIEW
Working on the T812
The T812 camera can be disassembled easily using standard tools. The only
special tool needed is the T812 C spanner which is used to separate the rod
adaptor from the camera head.
Tools
In addition to the Allen key set, tweezers and screwdrivers, a pair of long-nosed
pliers is needed for disassembly of the rod adaptor. If the counter rotate motor
needs to be replaced, a soldering iron will be required, all other assemblies and
PCB’s use connector pairs.
Fault Finding Tools
An oscilloscope is useful, but not mandatory for tracing problems. It is useful for
checking that the IIC Bus is operational, but most faults have obvious causes
(such as when a motor stops operating) and most electrical tests can be
performed using a standard digital multimeter.
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 4
T812 ROD ADAPTOR BLOCK DIAGRAM
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T812 ROD ADAPTOR
T812 Rod Adaptor
The Rod Adaptor comprises two active PCB’s, the processor (812/22) and the
power supply (812/21). The two are interconnected by the 812/23 pogo PCB
which is also the interface to the camera head. The rear pogo PCB connects to
the T8 4 termination and power is routed through the processor, via the 812/23
PCB to the power supply PCB. The power supply takes the 24V from the T8 4
and converts it to 5V and 15.6V by two switched-mode supplies.
The processor PCB is the master controller for all functions. It also contains a
video buffer and the data transceiver. There are two top-surface connectors, the 5-
way is used for programming, the 3-way can be used to connect to the camera
test jig and has Camera+ve, Camera-ve and Video+ve available in that order.
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 6
T812 ROD ADAPTOR
The picture to the right shows the connections
through to the camera head. The Rod Adaptor
can be connected to the camera test jig or a
T8 4 system and switched ON to check the
basic functions of the assembly. Video will not
be present, but the voltages and the basic IIC
bus signals can be checked (these will be ~3V
in amplitude).
The loss of any of these voltages or signals
would indicate that the Rod Adaptor is faulty.
This assembly should demand around 3 mA
@ 24V when not connected to the camera
head.
T812 ROD ADAPTOR - DISASSEMBLY
1). Hold the Rod Adaptor in your left
hand and give the end of the spanner a
sharp blow. This will loosen the
threaded boss, the Rod Adaptor can
now be unscrewed from the Camera
Head.
2). Remove two Pozi-drive screws as
shown to the right.
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 7
T812 CAMERA ROD ADAPTOR
3). Remove the 2.5 x 3 grub screw 4). Fit a pair of long-nose pliers to the
two vacant screw-holes and unscrew
the adaptor body
5). Remove the two remaining screws,
the collar can now be removed 6). Remove the pogo PCB by levering
at the screws with a flat screwdriver
7). Remove all eight securing screws 8). Disconnect from rear pogo PCB
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 8
T812 CAMERA HEAD
T812 Camera Head
The camera head consists of two major
sub-assemblies, the pan assembly and
the rotate assembly. The rotate assembly
contains a single active PCB which con-
tains a slave processor, EEPROM, incli-
nometer and motor driver for the rotate
motor.
The slave processor is employed to com-
municate with the inclinometer and motor
driver. All commands and data to/from the
processor PCB is sent and received via
the IIC bus.
The pan mechanism contains five active
PCB’s which also form the interconnec-
tions through to the final active PCB, the
camera sensor. In order, these are:
Pan sensor PCB (812/11), this measures
the pan position and contains two ADC’s
Pan motor PCB (812/1 ), this contains
the pan motor driver and an IIC port
Counter rotate PCB (812/ 8), this con-
tains the LED driver, motor driver and liq-
uid lens driver
Counter rotate sensor PCB (812/14), this contains the counter rotate sensor, 3V
regulator (for the sensor PCB) and a video buffer
Camera sensor PCB (812/15), this contains the video sensor and circuitry to drive
it. It only requires an input of 3V to produce a full composite video output
On the lower part of the pan assembly is a slipring (812/12) used to pass signals
through from the rotate assembly. There is a separate LED PCB that is passive, it
only contains two 5W LED’s
Troglotech T812 Pan & Tilt Camera Workshop Manual Page 9
T812 CAMERA HEAD - PAN DISASSEMBLY
1). Remove both 2.5 x 3 grub screws 2). Remove 3 x Pozi screws to remove
the buffer and unlock the mechanism
3). Remove one of the Allen bolts from
the pan cover and drop a 2mm Allen
key into the vacant hole. Turn the pan
mechanism slowly clockwise until the
Allen key drops into an indent in the
locking collar. Use slight force to rotate
the pan assembly further clockwise by
a further 4 degrees until the pan as-
sembly stops turning. This will unlock
the collar from the rotate assembly.
4). Carefully lever the pan assembly
from the rotate assembly as shown
above. Ensure that neither assembly is
marked. The pressure needed to re-
move the assembly is only required to
overcome to stiction of a single o-ring. If
more pressure is required move the
collar more by using the above process
in both directions to release the bayo-
net fitting.
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T812 CAMERA HEAD - PAN DISASSEMBLY
5). Carefully remove the fibre seal 6). Remove 3 x Allen bolts
7). Remove 2 x Pozi screws 8). Carefully lever the pan assembly
apart at this interface
Autres manuels pour T812
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