CANBUS connection to GDU G3X 460's

Hi,

I have asked this question to G3Xpert, but no reply as yet.

There are 2 CanBus connections for the Garmin GDU460 either in connector P4X01 or connector P4X02. I have twin G3X GDU's (my Left PFD) and my GDU460 (Right). My GSU is attached to the rear of GDU460 PFD Left.

According to page 26-4 of the G3X installation manual I should check with Garmin to confirm which connection is correct for my setup. Page attached to this email.

For the GDU460 (Left PFD) which connector should I connect my CanBus Connector P4X01 Pin 1 and 2 OR CanBus Connector P4X02 Pin 45 and 46.

and same question for the GDU460 (Right).

My CanBus route is:

GSA28 - GMU11 - GEA24 - GAD27 - GSU25 - GDU460 (Left) - GMC507 - GMA245 - G5 - GDU460 (Right) - GSA28

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Extract from Manual:

26.4 GDU 4XX (Display Unit)

26.4.1 P4501/4601/4701 (P4X01) Connector
The P4501/4601/4701 connector (referred to as P4X01 connector in this section) can be used for connections to the GSU 25 when mounting the GSU25 to the back of the GDU 4XX (Figure 8-2).This mounting method may not be recommended for all installations, contact Garmin for details before using this method.
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Regards John

P4X02 Pin 45 and 46 for both.

Connector 4602 is used for installations where the GSU25 is remotely mounted. Connector 4601 is only used when mounting the GSU25 directly on the back of the GDU.

GDU CAN Connection

design4p said:

Hi,

I have asked this question to G3Xpert, but no reply as yet.

There are 2 CanBus connections for the Garmin GDU460 either in connector P4X01 or connector P4X02. I have twin G3X GDU's (my Left PFD) and my GDU460 (Right). My GSU is attached to the rear of GDU460 PFD Left.

According to page 26-4 of the G3X installation manual I should check with Garmin to confirm which connection is correct for my setup. Page attached to this email.

For the GDU460 (Left PFD) which connector should I connect my CanBus Connector P4X01 Pin 1 and 2 OR CanBus Connector P4X02 Pin 45 and 46.

and same question for the GDU460 (Right).

My CanBus route is:

GSA28 - GMU11 - GEA24 - GAD27 - GSU25 - GDU460 (Left) - GMC507 - GMA245 - G5 - GDU460 (Right) - GSA28

----------------------------------------------------------------
Extract from Manual:

26.4 GDU 4XX (Display Unit)

26.4.1 P4501/4601/4701 (P4X01) Connector
The P4501/4601/4701 connector (referred to as P4X01 connector in this section) can be used for connections to the GSU 25 when mounting the GSU25 to the back of the GDU 4XX (Figure 8-2).This mounting method may not be recommended for all installations, contact Garmin for details before using this method.
--------------------------------------------------------------------
Regards John

Click to expand...

As a few other's have mentioned, the P4X01 will only be used if the GSU 25 is connected directly to the back of the display. Otherwise to create a CAN node at the GDU, use the P4X02 connector, pins 45 and 46.

You should not run out of RS232 ports with 2 GDU's on board, but the RS232 port on P4X01 is hard coded for Garmin Instrument data and can be used for a few specific purposes. The Garmin Instrument data setting will work to wire either the GEA 24 or GSU 25 backup data path to the display. This is technically a '6th' serial port, but it cannot be set to any setting besides Garmin Instrument data.

Thanks,

Justin

Thank you for the replies - 4 at the moment.

It would appear that 2 people have said use 46X01 and 2 people have said use 46X02. This would indicate that either will work.

I would like to know the technical reason for connecting to one rather than the other.

I suppose it would be prudent to follow the G3Xpert method.

I would like to ask if I use Pin 1 & 2 on connector 46X01 for my Left hand (PFD) GDU, what connections should I use on my Right Hand GDU 460?

Regards John

CAN bus termination

design4p said:

Thank you for the replies - 4 at the moment.

It would appear that 2 people have said use 46X01 and 2 people have said use 46X02. This would indicate that either will work.

I would like to know the technical reason for connecting to one rather than the other.

I suppose it would be prudent to follow the G3Xpert method.

I would like to ask if I use Pin 1 & 2 on connector 46X01 for my Left hand (PFD) GDU, what connections should I use on my Right Hand GDU 460?

Regards John

Click to expand...

There is only 1 reason to use pins 1 and 2 on the P4X01 connector, to add the GSU 25 to the CAN bus when the GSU 25 is mounted directly to the display. This is not the normal method of adding an LRU to the CAN bus, and this is the only case in which you would do so in this manner. You can think of it as an auxiliary node of sorts, rather than being inserted into the daisy chain directly, it is connected to the PFD through the P4X01 connector, and the PFD itself is inserted into the daisy chain through the P4X02 connector.

Using the P4X01 is completely optional, you can insert the GSU 25 directly into the daisy chain as its own node, rather than through the P4X01 connector if you would like.

Your PFD has a GSU 25 attached directly to it, to use the P4X01 connector, wire the 9 pin connector on the GSU 25 to the P4X01 connector on the PFD, pin for pin. Then wire the PFD into the CAN bus normally, using the P4X02 connector to insert it into the daisy chain, using pins 45 and 46. The GAD 27 and GMC 507 will be adjacent to it on either side of the bus.

Do not use the P4X01 connector on the MFD. Same thing here, use the P4X02 connector to insert it into the daisy chain, pins 45 and 46.

Thanks,

Justin

What do you gain by using the P4X01 connector?

The P4X01 connector pins 1 and 2 are not normal CAN Bus connections, but rather they effectively marry the GSU 25 to the GDU so the GSU doesn't have to be included in your CAN Bus harness string when you make it. It's an optional convenience that uses a CAN Bus node internal to the GDU. When the GDU and GSU are physically attached this optional connection integrates those two LRUs so no provision for the GSU needs to be made in the harness. That's it. So with respect to CAN Bus planning the P4X01 can be ignored and the GSU can be included in the Can Bus harness chain in a conventional fashion on the P4X02 connector pins 45 & 46, whether it's attached to the back of the GDU or not. No extra thinking required.

Further Question on this old thread.

Is it possible to terminate the Canbus at the GSU attached to P4601?

Also, on P4601 pins 6-9 are ground, power, power, ground. are these meant to pass power to the GSU, or do they need to be supplied with Ships power/ground?

Thanks...

Pdp7427 said:

Further Question on this old thread.

Is it possible to terminate the Canbus at the GSU attached to P4601?

Also, on P4601 pins 6-9 are ground, power, power, ground. are these meant to pass power to the GSU, or do they need to be supplied with Ships power/ground?

Thanks...

Click to expand...

If you are talking about terminating the whole canbus at the GSU attached to P4601 then no. The canbus node in P4601 is basically a different node than the one everything else is connected to from P4602. Also the power connection on P4601 are out to the GSU so they don't need to be connected to ships power/ground. Those come through the connections on P4602.

ColoradoSolar said:

If you are talking about terminating the whole canbus at the GSU attached to P4601 then no. The canbus node in P4601 is basically a different node than the one everything else is connected to from P4602. Also the power connection on P4601 are out to the GSU so they don't need to be connected to ships power/ground. Those come through the connections on P4602.

Click to expand...

Thanks for the quick reply. this does help simplify things.

Patrick

On my aircraft I used the can from the 2 connectors on PFD P4X01 and P4X02 no issue

I verified with Garmin when I did my panel upgrade 2 years ago about this and CAN is interconnected inside PFD/MFD (GDU) P4X01 and P4X02

my CAN path is :

GMU 11 to GSU25 to P4X01 on MFD, From P4X02 MFD to G5 to GMA 245 to GAD 29 to GMC 507 to P4X02 on PFD, from P4X01 on MFD to GEA 24 to GAD 27 to GSA 28 Yaw to GSA 28 Pitch to GSA 28 ROLL.

More than 100 hours with this setup and everything perfect except the recall on GSA28... another story....

Regards

Louis

This from the install manual:

GDU displays communicate with other LRUs using the CAN bus (with optional RS-232 backup paths supported for some LRUs) and with other devices using RS-232.

Those "optional" RS-232 backup paths include GSU & GEA data directly to a GDU. (See install manual for proper pins). I HIGHLY recommend you wire in this simple and very useful backup path. In case of total CAN bus failure you will lose all CAN communication capabilities. If CAN is your only connection for GSU & GEA, none of the data will be displayed anywhere even though the device is still working. If you have the backup RS-232, the data will be displayed on the GDU that it is wired to. In a multi GDU installation, wire the GSU & GEA RS-232 to whichever display is your primary location. (ex. GSU to PFD1, GEA to MFD)