Hardware Installation¶

Mechanical¶

Veronte Autopilot 4x is covered with an aluminium enclosure with enhanced EMI shielding and IP protection, with 750 g as total weight.

Pressure lines¶

Veronte Autopilot 4x has seven redundant pressure input lines; four for static pressure to determine the absolute pressure and three for pitot in order to determine the dynamic pressure.

For the fittings it is recommended to use a polyurethane tube of 2.5 mm inner diameter and 4 mm outer diameter.

Pressure Intake
- Pressure intakes must be located in order to prevent clogging.
- Do not install pressure intakes on the propeller flow.
- Design pressure tubing path in order to avoid tube constriction.
Static Pressure
- It is not recommended to use inside fuselage pressure if it is not properly vented.
Pitot Tube
- Pitot tube must be installed facing the airflow.
- It is recommended to install it near the aircraft’s x axis in order to avoid false measures during manoeuvres.
- For low-speed aircraft it is recommended at least 6.3 mm tubes to prevent any rain obstruction.

../_images/autopilot_4x_pressure_ports.png

Location¶

The location of Veronte Autopilot 4x has no restrictions. It is only required to configure its relative position respect to the centre of mass of the aircraft and the GNSS antenna. The configuration of the location of each Autopilot 1x can be easily configured using 1x PDI Builder.

Orientation¶

The orientation of Veronte Autopilot 4x has no restrictions either. It is only required to configure axes respect to the aircraft by means of a rotation matrix or a set of correspondences between axes. The configuration of the orientation can be easily configured using 1x PDI Builder for each Autopilot 1x.

Axes are printed on the Autopilot 4x box. Aircraft coordinates are defined by the standard aeronautical conventions, shown in the following figure.

../_images/aircraft-axis.jpg — **Aircraft Coordinates (Standard Aeronautical Convention)**¶

Vibration Isolation¶

Although Veronte Autopilot 4x rejects noise and high-frequency vibration modes with electronic filters, there may be situations where external isolation is needed.

Autopilot 1x can be mounted in different ways in order to reject the airframe vibration, but it is recommend to use the Damping System designed for that porpuse. It covers a wide frequency range of different aircraft types.

Note

The user should take into account that wiring should be loose enough so that vibrations are not transmitted to Autopilot 4x.

Damping System¶

Embention offers the Damping System as a solution to isolate Veronte Autopilot 4x from vibrations.

Important

Only effective with Autopilot 4x in horizontal position.

This damping system weighs 76 g.

../_images/dampsystem.png — **Damping System**¶

Warning

The Damping System is designed for version 1.8 of Autopilot 4x.

Dimensions¶

Assembly steps¶

To assembly the Damping System into a vehicle with an Autopilot 4x, read the following steps.

Remove the six nuts located under the platform.

Step 1¶
Screw the platform on the aircraft frame. The included screws have M3.

Step 2¶
Screw the Autopilot 4x on the Damping system.

Step 3¶

../_images/dampsystem_result.png — **Result**¶

Antenna Integration¶

The system uses different kinds of antenna to operate, they must be installed on the airframe. Here you can find some advice for obtaining the best performance and for avoiding antenna interferences.

Antenna Installation
- Maximize separation between antennas as much as possible.
- Keep antennas far away from alternators or other interference generators.
- Always isolate the antenna ground panel from the aircraft structure.
- Make sure antennas are securely mounted.
- Always use high-quality RF wires minimising the wire length.
- Always follow the antenna manufacturer manual.
- SSMA connections shall be tightened applying 1Nm of torque.
- For all-weather aircraft, insert SSMA lightning protectors.
GNSS Antenna
- Antenna top side must point to the sky.
- Install them on a top surface with direct sky view.
- Never place wires or parts made of memetal or carbon above the antenna.
- It is recommended to install antennas on a small ground plane.
- For all-weather aircrafts, insert SSMA lightning protectors.

Recommended specifications for GNSS antennas

Specifications	Range
Antenna frequency L1	1561.098 MHz to 1602 MHz
Antenna frequency L2	1207.14 MHz to 1246 MHz
Amplifier gain	17 dB to 35 dB
Out-of-band rejection	40 dB Note Higher values are preferable. 30dB is considered the minimum acceptable value.
Polarization	RHCP (Right-Hand Circular Polarization)
Minimum supply voltage	2.7 V to 3.3 V
Maximum supply current	50 mA

Electrical¶

Power supply¶

Autopilot 4x can use unregulated DC (6.5 V to 36 V) for the internal Veronte autopilots and also for the Management Board. All power supply pins are not common. It is possible to supply them with different voltages since they are internally protected with diodes. Nonetheless, all power supply pins must be connected to a power supply, in order to guarantee that Autopilot 4x will work in case of failing one of them. These pins are summarized in the following table:

Connector	PIN	Signal
Main Connector	68	BAT_0
	67	BAT_1
	64	BAT_2
Arbiter Connector	68	VCC_ARBITER

LiPo batteries between 2S and 8S can be used without voltage regulation. Remaining battery can be controlled by the internal voltage sensor and by configuring the voltage warnings on the PC application.

For higher voltage installations, voltage regulators must be used. For dimensioning voltage regulators take into account that a blocked servo can activate regulator thermal protection.

Warning

Power Veronte Autopilot 4x out of the given range can cause irreversible damage to the system. Please read carefully the manual before powering the system.

Autopilots and servos can be powered by the same or different batteries. In case there are more than one battery on the system, a single point ground union is needed to ensure a good performance. The ground signal should be isolated from other system ground references (e.g. engines).

It is recommendable to use independent switches for autopilot and motor/actuators. During the system initialization, PWM signal will be fixed to low level (0V), please make sure that actuators/motor connected support this behavior before installing a single switch for the whole system.

Power Domains¶

Veronte Autopilot 4x has two internal power domains (A and B). Power domains are isolated each other; hence, if one of them fails, the other one will remain operational. Many of the signals on the pinout are powered by one power domain.

Separated power domains allow to manage redundancy against internal power failures. For example, if the aircraft requires to measure a critical temperature of an external device, the user can use two different analog sensors and connect them to analog inputs of different power domains. One option for this example is connecting them to pin 38 (domain A) and pin 22 (domain B). Thus, if there is an internal failure and power domain A fails, the autopilot will still read measurements from pin 22.

Any power supply pin (pins 64, 67 and 68 from Main Connector and pin 68 from Arbiter Connector) powers both domains. Nonetheles, this is independent of the power supply for each internal Autopilot 1x. Since pins 64, 67 and 68 from Main Connector power one single autopilot (appart from power domains).

Pinout¶

Warning

Pins can transfer 2 A as maximum current.

Warning

Check the pin number before connecting. The color code is repeated 3 times due to the amount of pins. First section (yellow) corresponds to pins 1-30, the second section (blue) to pins 31-60 and the third one (red) to pins 61-68. Pin number increases following the black line of the pictures above: counterclockwise for the connector and clockwise for the plug.

Main Connector pinout¶

PIN	Signal	Type	Internal Power Domain	Description
1	I/O_0_MUXED	I/O	A	MUXED PWM / Digital I/O signal (0-3.3V) Warning Each pin withstands a maximum current of 1.65 mA.
2	I/O_1_MUXED	I/O	B
3	I/O_2_MUXED	I/O	A
4	I/O_3_MUXED	I/O	B
5	I/O_4_MUXED	I/O	A
6	I/O_5_MUXED	I/O	B
7	I/O_6_MUXED	I/O	A
8	I/O_7_MUXED	I/O	B
9	GND*	GROUND		Ground pin for signals 1-8
10	I/O_8_MUXED	I/O	A	MUXED PWM / Digital I/O signal (0-3.3V) Warning Each pin withstands a maximum current of 1.65 mA.
11	I/O_9_MUXED	I/O	B
12	I/O_10_MUXED	I/O	A
13	I/O_11_MUXED	I/O	B
14	I/O_12_MUXED	I/O	A
15	I/O_13_MUXED	I/O	B
16	I/O_14_MUXED	I/O	A
17	I/O_15_MUXED	I/O	B
18	GND*	GROUND		Ground pin for signals 10-17
19	MUXED_RS232_TX	OUTPUT	A	MUXED RS-232 output
20	MUXED_RS232_RX	INPUT	A	REDUNDANT RS-232 input
21	V2_USB_DP	I/O		Autopilot 2 USB positive data line
22	ANALOG_3	INPUT	B	REDUNDANT analog input (0-36V)
23	ANALOG_4	INPUT	B	REDUNDANT analog input (0-36V)
24	V2_USB_DN	I/O		Autopilot 2 USB negative data line
25	CANA_ARB_P	I/O	A	CAN-bus interface. It supports data rates up to 1 Mbps. A 120 Ohm Zo is required and twisted pair is recommended.
26	CANA_ARB_N	I/O	A
27	GND*	GROUND		GROUND pin for buses (except USB)
28	CANB_ARB_P	I/O		CAN-bus interface. It supports data rates up to 1 Mbps. A 120 Ohm Zo is required and twisted pair is recommended
29	CANB_ARB_N	I/O
30	V2_USB2_GND	GROUND		Autopilot 2 USB ground
31	I2C_CLK	OUTPUT A		MUXED Clock line for I2C bus (0.3V to 3.3V)
32	I2C_DATA	I/O	A	MUXED data line for I2C bus
33	GND*	GROUND		Ground for 3.3V power supply
34	V1_ARB_TX	OUTPUT		Microcontroller UART transmitter for Autopilot 1
35	V1_ARB_RX	INPUT		Microcontroller UART receiver for Autopilot 1
36	V2_ARB_TX	OUTPUT		Microcontroller UART transmitter for Autopilot 2
37	V2_ARB_RX	INPUT		Microcontroller UART receiver for Autopilot 2
38	ANALOG_0	INPUT	A	REDUNDANT analog input (0-36V)
39	ANALOG_1	INPUT	A
40	ANALOG_2	INPUT	A
41	GND*	GROUND		Ground signal for buses
42	V3_USB_DP	I/O		Autopilot 3 USB positive data line
43	V3_USB_DN	I/O		Autopilot 3 USB negative data line
44	GND*	GROUND		Ground signal for buses
45	V3_ARB_TX	OUTPUT		Microcontroller UART transmitter for Autopilot 3
46	V3_ARB_RX	INPUT		Microcontroller UART receiver for Autopilot 3
47	GND*	GROUND		Ground signal for buses
48	GND*	GROUND		Ground signal for buses
49	V3_USB3_GND	GROUND		Autopilot 3 USB ground
50	OUT_RS485_P	OUTPUT	B	MUXED non-inverted output RS-485 bus
51	OUT_RS485_N	OUTPUT	B	MUXED inverted output RS-485 bus
52	IN_RS485_N	INPUT		REDUNDANT inverted inout RS-485 bus
53	IN_RS485_P	INPUT		REDUNDANT non-inverted input RS-485 bus
54	RS485_GND	GROUND		Ground for RS-485 bus
55	EQEP_A	INPUT	A for autopilots 1 and 2 B for autopilot 3	Encoder quadrature redundant input A (0-5V)
56	EQEP_B	INPUT		Encoder quadrature redundant input B (0-5V)
57	EQEP_S	INPUT		Encoder strobe redundant input (0-5V)
58	EQEP_I	INPUT		Encoder index redundant input (0-5V)
59	GND*	GROUND		Autopilot 3 ground pin
60	V1_USB_DP	I/O		Autopilot 1 USB positive data line
61	V1_USB_DN	I/O		Autopilot 1 USB negative data line
62	V1_USB1_GND	GROUND		Autopilot 1 USB ground
63	GND*	GROUND		Ground signal for buses
64	BAT_2	POWER		Autopilot 3 power supply (6.5 to 36V)
65	GND*	GROUND		Autopilot 2 ground pin
66	GND*	GROUND		Autopilot 1 ground pin
67	BAT_1	POWER		Autopilot 2 power supply (6.5 to 36V)
68	BAT_0	POWER		Autopilot 1 power supply (6.5 to 36V)

Warning

Common grounds are marked with *.

Note

MUXED (multiplexed) signals are connected to the Autopilot 1x decided by the Management Board, then only the selected autopilot is connected to MUXED pins.

REDUNDANT signals are connected to the three inner autopilots, so all of them receive the same REDUNDANT signals.

To know the differences between version 1.2 and 1.8 (this one), read the Pinout changes from Autopilot 4x 1.2 - Troubleshooting section of the present manual.

Arbiter Connector pinout¶

Although being the same component, Main Connector and Arbiter connector are polarized differently, but they have different mechanical connections to avoid wiring swapping.

PIN	Signal	Type	Internal Power Domain	Description
1	I/O_0_EXTERNAL	I/O	A	External MUXED PWM / Digital I/O signal (0-3.3V). In case of employing an additional external autopilot, its pins I/XX must be connected here. Each signal I/O_XX_EXTERNAL will be sent to I/XX of Main Connector if the arbiter commands it. Warning Input current must be limited to 25 mA for each I/O EXTERNAL pin.
2	I/O_1_EXTERNAL	I/O	B
3	I/O_2_EXTERNAL	I/O	A
4	I/O_3_EXTERNAL	I/O	B
5	I/O_4_EXTERNAL	I/O	A
6	I/O_5_EXTERNAL	I/O	B
7	I/O_6_EXTERNAL	I/O	A
8	I/O_7_EXTERNAL	I/O	B
9	I/O_8_EXTERNAL	I/O	A
10	I/O_9_EXTERNAL	I/O	B
11	I/O_10_EXTERNAL	I/O	A
12	I/O_11_EXTERNAL	I/O	B
13	ARBITER_ANALOG_7	INPUT		Arbiter analog input (0-36V)
14	EXTERNAL_ANALOG_0	OUTPUT	A	External analog signal (0-3V). This is the analog signal from ANALOG_0 on Main Connector, which is reduced from 0-36V to 0-3V.
15	EXTERNAL_ANALOG_1	OUTPUT	A	External analog signal (0-3V). This is the analog signal from ANALOG_1 on Main Connector, which is reduced from 0-36V to 0-3V.
16	EXTERNAL_ANALOG_2	OUTPUT	A	External analog signal (0-3V). This is the analog signal from ANALOG_2 on Main Connector, which is reduced from 0-36V to 0-3V.
17	EXTERNAL_ANALOG_3	OUTPUT	B	External analog signal (0-3V). This is the analog signal from ANALOG_3 on Main Connector, which is reduced from 0-36V to 0-3V.
18	FTC_VOTING_B	OUTPUT	B	This pin is an open drain output (0 - 48V), which is open or connected to GND depending on the FTS signals of the Autopilots 1x. This logic is implemented at the Voting Stage, explained in detail in the Flight Termination System section of this manual. Use this pin for an emergency device; for example the ground of a relay that activates a parachute. FTC_VOTING_A (pin 53) and FTC_VOTING_B (pin 18) do the same function, but they have dissimilarity.
19	EXT_RS232_TX	INPUT	A	In case of employing an additional external autopilot, its pin RS 232 TX must be connected here. If arbiter decides to multiplex this signal, it will be transmitted to MUXED_RS232_TX on Main Connector with RS232 protocol.
20	EXT_RS232_RX	OUTPUT	A	In case of employing an additional external autopilot, its pin RS 232 RX must be connected here. If arbiter decides to multiplex this signal, it will be transmitted to MUXED_RS232_TX on Main Connector with RS232 protocol.
21	IN_RS485_P	OUTPUT		This pin is connected with IN_RS485_P from Main Connector
22	IN_RS485_N	OUTPUT		This pin is connected with IN_RS485_N from Main Connector
23	EXT_OUT_RS485_P	INPUT	B	In case of employing an additional external autopilot, its pin OUT_RS485_P must be connected here. If arbiter decides to multiplex this signal and EXT_DETECT of Arbiter Connector is connected to GND, it will be transmitted to OUT_RS485_P on Main Connector with RS232 protocol
24	EXT_OUT_RS485_N	INPUT	B	In case of employing an additional external autopilot, its pin OUT_RS485_N must be connected here. If arbiter decides to multiplex this signal and EXT_DETECT of Arbiter Connector is connected to GND, it will be transmitted to OUT_RS485_N on Main Connector with RS232 protocol
25	CANA_P_ARB_A	I/O		This pin is connected with CANA_ARB_P from Main Connector
26	CANA_N_ARB_A	I/O		This pin is connected with CANA_ARB_N from Main Connector
27	ARBITER_ANALOG_8	INPUT		Arbiter analog input (0-36V)
28	CANB_P_ARB_B	I/O		This pin is connected with CANB_ARB_P from Main Connector
29	CANB_N_ARB_B	I/O		This pin is connected with CANB_ARB_N from Main Connector
30	OUT_RS485_ARB_P	OUTPUT	A	Non-inverted output for arbiter A RS-485 bus
31	OUT_RS485_ARB_N	OUTPUT	A	Inverted output for arbiter A RS-485 bus
32	IN_RS485_ARB_N	INPUT	A	Inverted output for arbiter A RS-485 bus
33	IN_RS485_ARB_P	INPUT	A	Non-inverted input for arbiter A RS-485 bus
34	TX_OUT_P	OUTPUT	A	Arbiter A ARINC positive output
35	TX_OUT_N	OUTPUT	A	Arbiter A ARINC negative output
36	RIN1_ARINC_P	INPUT	A	Arbiter A ARINC positive input
37	RIN1_ARINC_N	INPUT	A	Arbiter A ARINC negative input
38	GND*	GROUND		Ground pin for buses
39	SCL_A_OUT_ARB	OUTPUT	A	Clock signal for arbiter A I2C bus
40	SDA_A_OUT_ARB	I/O	A	Data signal for arbiter A I2C bus
41	DSP_232_RX_B	INPUT	A	Arbiter A RS-232 input B
42	DSP_232_TX_B	OUTPUT	A	Arbiter A RS-232 output B
43	DSP_232_RX_A	INPUT	A	Arbiter A RS-232 input A
44	DSP_232_TX_A	OUTPUT	A	Arbiter A RS-232 output A
45	GND*	GROUND		Ground pin for analog signals
46	ARBITER_ANALOG_0	INPUT	A	Arbiter A analog input (0-36V)
47	ARBITER_ANALOG_1	INPUT	A
48	ARBITER_ANALOG_2	INPUT	A
49	ARBITER_ANALOG_3	INPUT	A
50	ARBITER_ANALOG_4	INPUT	A
51	ARBITER_ANALOG_5	INPUT	A
52	ARBITER_ANALOG_6	INPUT	A
53	FTC_VOTING_A	OUTPUT	A	This pin is an open drain output (0 - 48V), which is open or connected to GND depending on the FTS signals of the Autopilots 1x. This logic is implemented at the Voting Stage, explained in detail in the Flight Termination System section of this manual. Use this pin for an emergency device; for example the ground of a relay that activates a parachute. FTC_VOTING_A (pin 53) and FTC_VOTING_B (pin 18) do the same function, but they have dissimilarity.
54	GPIO_8_ARB	I/O	A	Arbiter A PWM / digital I/O signal (0-3.3V)
55	GPIO_9_ARB	I/O	A	Arbiter A PWM / digital I/O signal (0-3.3V)
56	WD_EXT	INPUT	A	Watchdog signal from external autopilot to arbiter A (0-3.3V)
57	EXT_DETECT	INPUT	A	Connect to GND if external autopilot is connected, otherwise keep open
58	GND*	GROUND		Ground signal for GPIO
59	GPIO_0_ARB	I/O	A	Arbiter A PWM / digital I/O signal (0-3.3V)
60	GPIO_1_ARB	I/O	A
61	GPIO_2_ARB	I/O	A
62	GPIO_3_ARB	I/O	A
63	GPIO_4_ARB	I/O	A
64	SEL_AP	OUTPUT	A	CAP signal indicating the AP selected
65	FTS1_OUT	OUTPUT	A	Deadman signal from comicro
66	FTS2_OUT	OUTPUT	A	System OK bit
67	GND*	GROUND		Management Board ground
68	VCC_ARBITER	POWER		Power supply for Management Board (6.5 to 36 V)

Warning

Common grounds are marked with *.

Important

Apart from CAN buses, all communications are established only with arbiter A (I2C, RS-232, RS-485 and ARINC).

To know the differences between version 1.2 and 1.8 (this one), read the Pinout changes from Autopilot 4x 1.2 - Troubleshooting section of the present manual.

Harnesses¶

../_images/pinout_harness.png — **Pinout of Harness plug of both connectors**¶

Warning

A wire harness is a structured assembly of cables and connectors used to organize and manage wiring in electrical and electronic systems. It is designed to ensure a tidy and secure installation of cables, preventing tangles, electromagnetic interference, and facilitating maintenance.

The connection between Autopilot 4x and its harnesses is made through the following connectors:

Main Connector: HEW.LM.368.XLNP	Harness plug connector: FGW.LM.368.XLCT
Connector 4: HER.LM.368.XLNP	Harness plug connector: FGR.LM.368.XLCT

Veronte Autopilot 4x 1.8 has the following compatible harnesses:

For Main Connector
Veronte Harness Blue 68P	Veronte Harness CS for 1.8

Harness available on demand with the Embention reference P001114	Harness available on demand with the Embention reference P007695
For Connector 4: Veronte Harness Yellow 68P

Harness available on demand with the Embention reference P001118

Dimensions¶

Harness plug dimensions:

Connector FGW.LM.368.XLCT/FGR.LM.368.XLCT dimensions (cm)¶
Harness Blue/Yellow 68P wire gauge: 22 AWG
Cables lenght: 52 cm

Connector color code¶

Warning

PIN	Color code	PIN	Color code
1	White	35	Gray
2	Brown	36	Pink
3	Green	37	Blue
4	Yellow	38	Red
5	Gray	39	Black
6	Pink	40	Violet
7	Blue	41	Gray - Pink
8	Red	42	Red - Blue
9	Black	43	White - Green
10	Violet	44	Brown - Green
11	Gray - Pink	45	White - Yellow
12	Red - Blue	46	Yellow - Brown
13	White - Green	47	White - Gray
14	Brown - Green	48	Gray - Brown
15	White - Yellow	49	White - Pink
16	Yellow - Brown	50	Pink - Brown
17	White - Gray	51	White - Blue
18	Gray - Brown	52	Brown - Blue
19	White - Pink	53	White - Red
20	Pink - Brown	54	Brown - Red
21	White - Blue	55	White - Black
22	Brown - Blue	56	Brown - Black
23	White - Red	57	Gray - Green
24	Brown - Red	58	Yellow - Green
25	White - Black	59	Pink - Green
26	Brown - Black	60	Yellow - Pink
27	Gray - Green	61	White
28	Yellow - Green	62	Brown
29	Pink - Green	63	Green
30	Yellow - Pink	64	Yellow
31	White	65	Gray
32	Brown	66	Pink
33	Green	67	Blue
34	Yellow	68	Red

Flight Termination System (FTS)¶

The Flight Termination System determines the behavior of Autopilot 4x in case of severe failure. There are FTS output signals of 4x for failures of Autopilots 1x (FTC_VOTING_A and FTC_VOTING_B) and for failure of the Arbitration system (FTS1_OUT and FTS2_OUT).

Autopilots 1x failure - Voting Stage¶

Autopilot 4x FTS works based on a Voting Stage, a simple hardware circuit made of logic gates, which analyzes the FTS signals of each Autopilot 1x in order to determine if terminating the mission or not.

The FTS signals of Autopilots 1x, which correspond with the voting signals considered in the Voting Stage, are the following:

../_images/FTS_signals.svg — **Voting System Inputs**¶

Pin 63 - FTS_OUT_MPU: Its output is 0 V when the system is working as expected and 3.3 V when some error is detected.
Pin 64 - FTS2_OUT_MPU: Its output is 0 V when the system is working as expected and 3.3 V when some error is detected.
Pin 49 - FTS3_OUT_MPU: MPU alive voting signal. Its output is a square wave at [100,125] Hz.

Note

For further information regarding these pins, please refer to Pinout - Hardware Installation section in 1x Hardware Manual.

The functionality of the Voting Stage is to implement the following logic:

Isolate internal Flight Termination Units (FTUs) with failure. When a deadman signal indicates that an internal Veronte FTU has a failure, this FTU will be excluded from the voting scheme.
If all three internal FTUs are OK, then termination will occur if two of three FTUs detect that the vehicle is out of the restricted area.
If two FTUs are ok and one is dead, then termination will occur if one of the remaining FTUs detect that the vehicle is out of the restricted area.
If one FTU is ok and two are dead, then termination will occur if the remaining FTU detects that the vehicle is out of the restricted area.
If all three FTUs are dead, terminate the mission.

In Autopilot 4x, there are two Voting Systems available whose output signals are FTC_VOTING_A and FTC_VOTING_B (pins 53 and 18).

Note

These pins will be open in case of terminating the mission and connected to GND when continuing the mission.

Arbitration failure¶

The Management Board also includes two FTS pins in the Arbiter Connector:

Pin 65 - FTS1_OUT: Deadman signal. Its output is a square wave.
Pin 66 - FTS2_OUT: System OK. Its output will be 3.3 V when an error has been detected and 0V when the arbitration system is working normally.

Electrical diagram of CAN bus¶

Autopilot 4x requires two termination resistors (120 \(\Omega\)) to allow multiple CAN Bus devices to be connected to the same line.

Since there is already an internal 120 \(\Omega\) CAN resistor in the Autopilot 4x (connecting the line to CAN A or CAN B), it is only necessary to place an external 120 \(\Omega\) resistor at the end of the cable:

../_images/can_resistor.png — **CAN resistor**¶