Troglotech T815 Instruction manual

Troglotech T815 Crawler Workshop Manual Page 1
WORKSHOP MANUAL — T815 CRAWLER
Troglotech Ltd Phone [phone]
Unit 1, 3 Penns Road Phone [phone]
Petersfield Fax [phone]
Hampshire Email [e-mail]
GU32 2EW Web www.troglotech.com

Troglotech T815 Crawler Workshop Manual Page 2
T815 CRAWLER - OVERVIEW
T815 Crawler Overview—Motor Drives
MECHANICS:
The mechanical construction of the T815 crawler enables quick disassembly and
is simple to repair and maintain. NOTE: See https://youtu.be/H5bHqfwd2yg for
video of assembly instructions
The diagram above shows the plain chassis and the two motor/gearbox drive
units. These are manufactured by Troglotech and are not serviceable, in the
unlikely case of malfunction they can be replaced as assemblies and the failed
unit returned to Troglotech for investigation.
The motor drives contain a 3-phase brushless motor and a Troglotech-designed
cycloid gearbox to attain the torque requirements and available volume.
The drive units can be replaced by removing the side metalwork (containing the
drive axles, seals and idler gear) and PCB’s—Note that the drive units are
connected to the Motor Drive PCB’s by a flexible Kapton lead with a ZIF
receptacle at the end—this is disconnected by sliding the lock on the PCB—this
is best done with the Motor Drive PCB still fitted to the chassis

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T815 CRAWLER- OVERVIEW
T815 Crawler Overview—PCB’s
The diagram above shows the PCB positions the numbered balloons show the
order in which the PCB’s must be removed, they are connected in such a way
that only the correct order will allow them to be removed without damage.
NOTE: Removal of the Motor Drives (3 and 8) requires the disconnection of the
Kynar flexible connection from the ZIP sockets—be careful as these can be
damaged easily. Disconnection requires that the clasp is pushed towards the
flexible ribbon by around 2mm before it can be removed.
NOTE: Add a small amount of silicon grease between the motor drive PCB and
the pocket in which it is housed to conduct heat away from the driver whenever a
motor drive PCB is replaced

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T815 CRAWLER - OVERVIEW
T815 Crawler Overview—PCB’s
The diagram above shows the PCB positions the numbered balloons show the
order in which the PCB’s must be removed, they are connected in such a way
that only the correct order will allow them to be removed without damage.
NOTE: Removal of the Motor Drive (3) requires the disconnection of the Kynar
flexible connection from the ZIP sockets—be careful as these can be damaged
easily. Disconnection requires that the clasp is pushed towards the flexible ribbon
by around 2mm before it can be removed
NOTE: Add a small amount of silicon grease between the motor drive PCB and
the pocket in which it is housed to conduct heat away from the driver whenever a
motor drive PCB is replaced

Troglotech T815 Crawler Workshop Manual Page 5
T815 CRAWLER- OVERVIEW
T815 Crawler Overview—PCB’s
The diagram above shows the PCB positions the numbered balloons show the
order in which the PCB’s must be removed, they are connected in such a way
that only the correct order will allow them to be removed without damage.
NOTE: Removal of the Motor Drive (4) requires the disconnection of the Kynar
flexible connection from the ZIP sockets—be careful as these can be damaged
easily. Disconnection requires that the clasp is pushed towards the flexible ribbon
by around 2mm before it can be removed
NOTE: Add a small amount of silicon grease between the motor drive PCB and
the pocket in which it is housed to conduct heat away from the driver whenever a
motor drive PCB is replaced

Troglotech T815 Crawler Workshop Manual Page 6
T815 CRAWLER - OVERVIEW
T815 Crawler Overview—Drivetrain and External Parts
DRIVETRAIN:
The picture below shows the T815 drivetrain and external parts. The drivetrain
consists of six individual axles with integral gears and two Idler Gears. These parts
are attached to, or held in place by the Tractor Sides which are secured by 12
Allen bolts
To release the Tractor Sides it is good practice to loosen the Front Cover as this
can put force on the sides. The Rear Cover contains the Swivel Connection and
the Sonde Transmitter, it also has apertures for the rear camera and lighting
(both of which are fitted to the Processor/VID PCB)
The Front Cover contains the Camera Pogo PCB, this connects to the camera
(which can be either the T812 Pan & Tilt or the Forward View Camera)
The Connector Block connects to the inserted battery pack and is the input for
all electronics within the Tractor. This, along with the sonde assembly are the
only wired components, all other connections are connector pairs

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T815 CRAWLER- OVERVIEW
T815 Crawler Overview—Electronic Operation
The electronic operation of the Crawler is controlled by the Processor/VID PCB
(TC81511011). With a Battery Pack fitted to the Crawler the battery power is
disconnected from all PCB’s apart from the Processor and the TC81510011
Power Control PCB. The latter provides power to the Processor PCB via a 1K
resistor called ‘BAT SAFE’
BAT SAFE is regulated on the Processor PCB to provide a low-current 5V supply
for a sensing circuit as seen below. When the Display Unit is switched ON the
small voltage on Video+ve that is present at the end of the cable is detected by
this circuit. The detected voltage produces a HIGH level on ‘WAKE’ and this is
conducted to the Power Control PCB to switch ON the battery supply to the
complete electronics.
At switch ON the 5V power supply becomes active and is used to keep ‘WAKE’ at
a high level for a few seconds via C89—this period is long enough to allow the
Processor to start and hold ‘KEEP AWAKE’ high whilst the cameras produce video
and TTDS communications are established to ensure that the power remains ON.
Once the 5V supply is operational Video+ve will drop in DC voltage as the video
signal is transmitted.

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T815 CRAWLER - OVERVIEW
T815 Crawler Overview—Electronic Operation Continued
The picture below shows the battery switching section of the Power Control PCB.
If there is a high level on ‘WAKE’ then power is made available at Motor+ve via
IC11 which supplies power for the complete crawler including the Motor Drive
PCB’s and the PSU which provides the 5V and 15V supplies.
The picture below shows the Power Supply (TC81509011) which produces 5V and
15V from the Power+ve rail—it’s source is the Motor+ve supply from the Power
Control PCB—Motor+ve and Power+ve are kept separate through the Interconnect
PCB’s from the Power Control PCB to reduce electronic noise which may affect the
video picture.
This Power Supply is the voltage source for all the electronics and cameras on the
crawler, however the Motor+ve supply is used as a raw supply for the Motor Drives
and additional lighting (large lighthead and reversing lights). The voltage from the
battery can drop below 13V which is unsuitable for the T815 camera head which is
why a separate 15V supply is available.

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T815 CRAWLER- OVERVIEW
T815 Crawler Overview—Electronic Operation Continued
Once the Power Supply is established, the Processor continually communicates
with the Display Unit of the Cable Drum via TTDS signals that are present on
Video+ve. As long as TTDS data is stable and the data contains the
’KEEP_ALIVE_BIT’ (this is set as long as the Display Unit has the correct crawler/
drum software) the processor will hold ‘KEEP AWAKE’ high, which, in turn, holds
‘WAKE’ high. TTDS only works when either the front or rear camera is in
operation, TTDS needs a video signal to operate.
If data is not available the crawler will switch back OFF again. If this cycling
continues, it indicates that the voltage on Video+ve is present but TTDS data is
incorrect or missing. This behaviour will be seen if the software for the Display Unit
(both MAIN and COMMS) has not been updated; pre-T815 software does not
include the ’KEEP_ALIVE_BIT’ bit on TTDS data.
Once TTDS communications are established and the correct data is received the
processor will start communicating with the internal parts via IIC serial bus
The processor has a number of tasks:
 Continually send/receive TTDS data
 Initialise all IIC devices
 Initialise the T812 camera head (if fitted)
 Initialise the two motor drives to a safe state
 Communicate with the Display Unit via TTDS
 Select the video source between front and rear cameras
 Switch ON/OFF rear lights
 Switch ON/OFF large lighthead
 Initialise the accelerometer
 Read the accelerometer to get inclination data
 Transmit the inclination to Display Unit via TTDS
 Switch sonde ON/OFF
 Read EEPROM to get calibration data
 Get pressure sensor data and calculate true pressure
 Get IIC data from current/voltage monitors
 Calculate true voltage/current
 Transmit voltage/current to Display Unit via TTDS
 Calculate crawler orientation for auto-steering
 Determine maximum motor speed from voltage data

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T815 CRAWLER - OVERVIEW
T815 Crawler Overview—Electronic Operation Continued
Once the processor has initialised all PCB’s and the T812 camera it will operate
the crawler speed, direction and camera orientation and selection via commands
from the Display Unit via TTDS:
 Continually send/receive TTDS data
 Control the T812 camera head
 Control the motor drives speed and direction
 Select the video source between front and rear cameras
 Switch ON/OFF rear lights
 Switch ON/OFF large lighthead
 Read the accelerometer to get inclination data
 Switch ON/OFF the sonde
 Get pressure sensor data and calculate true pressure
 Get IIC data from current/voltage monitors
 Return Voltage/Current data via TTDS
 Calculate crawler orientation for auto-steering
 Determine maximum motor speed from voltage data
T815 Crawler Integration with AUTO DRUM:
The T850 Auto Drum system is designed to be a transparent addition to a
standard crawler system. However, the crawler changes its behaviour if the
Auto Drum is set to ‘AUTO’ and the crawler direction is set to reverse:
 The Auto Drum sends a ‘crawler passive’ command via TTDS
 The Display Unit accepts the ‘crawler passive’ command
 The Display Unit sends out a ‘crawler passive’ command to the crawler
 The crawler does not engage reverse and switches OFF the brakes
The behaviour above requires software to be upgraded in:
 The Crawler
 The MAIN Display Unit software
 The COMMS Display Unit software
Without these software upgrades the crawler will enable its motor drives in reverse
and the Auto Drum will pull the crawler slightly faster than the wheel speed, this
substantially increases the Auto Drum current demand.