Simrad TP10 Service Manual page 17

Issue 4.0 17/09/03
5 CIRCUIT DESCRIPTIONS
Tillerpilot Common PCB Assembly
Introduction. The PCB Assembly is a common item to all Wheelpilots and Tillerpilots. However,
when the PCB is used in the TP10 or WP10 those components concerned with NMEA and
CANBUS data are present but not in use, these components are highlighted in Red on the Circuit
Diagram Drawing No. E03372.
Supply and Regulation. The Tiller Pilots are designed to work from a 12 V source. Protection
against incorrect polarity is provided by D1 and D4. Capacitors C1and C3 are used as reservoirs
to hold up the supply voltage and reduce any supply dips. Protection against over-voltage spikes
is provided by Resistor R2 and Zener Diode ZD1 and Regulator REG1 provides a 5V regulated
supply. Transient Voltage Suppresser TVS1 protects the MOSFET drive transistors, TR10 to
TR13, from voltage spikes greater than +16V.
Microprocessor. Light Emitting Diodes LED1 to LED4 are driven from the microprocessor IC2
Ports P0.0 and P0.2 to P0.4 and turn OFF when the line goes HIGH via the transistor switches
TR2 to TR5. When the transistors are off, resistors R32, R34, R36 and R38 provide a low current
path for the LEDs to provide low level night illumination. The Audio Resonator AR1 is self
resonating and switches ON when Port P0.5 goes HIGH via the transistor switch TR1 and resistors
R59 and R60. The control key lines on Ports P4.0 to P4.4, normally pulled to +5V via resistors R7
to R11, are "scanned" by the microprocessor to detect if any of the switches have been operated
and pulled the line LOW.
NMEA Data In. NMEA data is optically isolated by IC5 and then fed into Port P2.4 of the
microprocessor. Transistors TR6, TR7 and TR8 and components D6, D7, D8, R17, R18 and R19
form a switch, protected from high voltages, driven from Port P0.1 of the microprocessor. The
switch is used to apply the synchronisation pulse (HR200_SYNC) to the NMEA line for products
employing a Hand (Remote) Controller.
CANBUS Data. CANBUS data in and out is driven by IC3 directly to and from Ports P2.1 and P2.0
respectively.
NB. Components shown in
when the PCB is used with WP10 or TP10. The cable loom to connect them is absent from these
products.
Configuration Links. The Links, L1, L2 and L3, are used to configure the Microprocessor
to either Wheelpilot or Tillerpilot operation and to model versions 10, 20 or 30 in
accordance with the table below:
LEGEND N / C Normally Closed (soldered)
N / O Normally Open (unsoldered)
RED on the circuit diagram, Drawing No. E03372, are not in circuit
1 Model
TP 10
WP 10
TP 20
TP 30
WP 30
Link 1 Link 2
N / C N / C
N / O N /C
N / C N / C
N / C N / O
N / O N / O
SIMRAD
Link 3
N / C
N / C
N / O
N / O
N / O
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