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IFD540 & STEC55x

Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=1924
Printed Date: 19 Feb 2020 at 9:39pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: IFD540 & STEC55x
Posted By: theronb
Subject: IFD540 & STEC55x
Date Posted: 08 Jan 2020 at 11:18pm
I just replaced my 530w with an IFD540.  I have a STEC55x that used to do GPSS with my 530w but that feature has since stopped working with the instsall of the IFD540.  Now when I press the GPSS function on the autopilot, it appears to be linked to the CDI.  If I turn the CDI, the autopilot will follow but will not do true GPSS.  The CDI appears to be working like a heading bug in GPSS mode.  Any help would be appreciated. Thanks.



Replies:
Posted By: oskrypuch
Date Posted: 09 Jan 2020 at 7:41am
My 55x is perfectly happy following the GPS track from my 540, using its own GPSS module. So it can certainly work. Ensure you have a flight plan loaded, and are in GPS mode in the 540.

There is one potential gotcha, the 55x when it boots up assumes a certain bus speed, and does not recalibrate. If you boot up the 55x before the 540 is on line, the two may never talk. It depends on the speeds you have set by default in each. That is easy to step around, just power up the 55x AFTER the 540 boots up. (or do a power cycle of the 55x if you didn't)  If I don't do that, then GPSS mode will not work in my 55x, it just gives an error message. I added a power down of my 55x, as a routine item on my after landing cleanup check list.

What CDI are you referring to? An analog CDI on your panel??

* Orest


Posted By: Cruiser
Date Posted: 09 Jan 2020 at 9:51am
what "GPSS function" are you pressing?
Do you press the NAV button on the Stec 55x twice ? and does the display indicate GPSS to the right of the NAV ?


Posted By: donemory
Date Posted: 09 Jan 2020 at 3:18pm
I think Orest is talking about the IFD540 GPS.  You should look upper right of the 540, it will say GPS or VLOC.  You turn the upper right knob to toggle between them.  Hope that helps. Don

-------------
Don


Posted By: theronb
Date Posted: 09 Jan 2020 at 3:32pm
Yes, I am pressing NAV twice to enable GPSS.  I get an error message when I press it twice.  The IFD540 is in GPS mode. If I press NAV once, it will enable NAV mode but I have to turn the HSI for the auto pilot to follow the course.  On my 530w, I could press NAV twice and it would follow the flight plan loaded on the 530w.  This is what I am trying to accomplish on the IFD540.


Posted By: oskrypuch
Date Posted: 09 Jan 2020 at 10:10pm
Originally posted by theronb theronb wrote:

Yes, I am pressing NAV twice to enable GPSS.  I get an error message when I press it twice.  The IFD540 is in GPS mode...


Read through my message again, the gotcha, that is exactly the problem I was describing, and your solution is simple. The reason it is responding to the analog CDI, is because the 55x had remained in NAV (vice GPSS) mode.

* Orest


Posted By: theronb
Date Posted: 09 Jan 2020 at 10:48pm
Originally posted by oskrypuch oskrypuch wrote:

Originally posted by theronb theronb wrote:

Yes, I am pressing NAV twice to enable GPSS.  I get an error message when I press it twice.  The IFD540 is in GPS mode...


Read through my message again, the gotcha, that is exactly the problem I was describing, and your solution is simple. The reason it is responding to the analog CDI, is because the 55x had remained in NAV (vice GPSS) mode.

* Orest

My panel has a separate power switch for the STEC.  I powered up the IFD540 fully and then flipped the switch on for the auto pilot.  I still received an error message after pressing the nav button twice.  I had a flight plan loaded and the ifd540 was in GPS mode.


Posted By: oskrypuch
Date Posted: 10 Jan 2020 at 11:16am
Originally posted by theronb theronb wrote:


My panel has a separate power switch for the STEC.  I powered up the IFD540 fully and then flipped the switch on for the auto pilot.  I still received an error message after pressing the nav button twice.  I had a flight plan loaded and the ifd540 was in GPS mode.


Ah, OK, then you have a wiring or setup issue. You need to get back to your dealer, he needs to get your 55x & IFD talking.

The 55x can be run with an external GPSS module, or through something like an ASPEN that has GPSS in it. Many dealers do not connect navigators directly to the 55x because of that, which is a real oversight. Again, don't know about your panel specifics or circumstances, but that may be an issue as well.

* Orest


Posted By: chflyer
Date Posted: 10 Jan 2020 at 3:14pm
Originally posted by oskrypuch oskrypuch wrote:

The 55x can be run with an external GPSS module, or through something like an ASPEN that has GPSS in it. Many dealers do not connect navigators directly to the 55x because of that, which is a real oversight. Again, don't know about your panel specifics or circumstances, but that may be an issue as well.

* Orest

Orest, I am considering replacing my S-TEC 30 (+ST-901 GPSS) with the 55X (172XP, so no 3100 or DFC90 option). Do I understand your comment to mean that when doing that I have the choice of keeping the external GPSS module or removing it and using the 55X internal GPSS? do you think it makes any difference, one vs the other?


-------------
Vince


Posted By: oskrypuch
Date Posted: 10 Jan 2020 at 4:57pm
No worries, the 55x is a great A/P, I've been flying it for a while and it does everything I need. Sure, I'd love to slip in a DFC, but that doesn't seem likely to happen.

YES, you could keep your current GPSS module. If you do, you then have the choice of using either the external GPSS, or the GPSS module built into your 55x. Using the 55x internal module is of greater advantage, as then you can access GPSS "armed" modes, like HDG->GPSS. Very handy. Also, then everything is done on the 55x, rather than reaching over somewhere else for one mode.

I have an ASPEN, and I ensured I had the 55x wired to accept the GPS output directly, and I normally use the 55x for activating all modes, including GPSS. The ASPEN remains a kind of backup. If you set the 55x for HDG, then you can toggle between HDG & GPSS on the ASPEN.

In your setting, not that much use to keeping it, and an external GPSS module generally has good value on the resale market. With a tag, it can go into any type plane.

* Orest


Posted By: rolfe_tessem
Date Posted: 12 Jan 2020 at 10:00am
I have a 55X and a 540 and all works as its supposed to.

As has been mentioned, when you press NAV twice, it goes to GPSS mode. One push of NAV will cause it to follow the CDI, as it is supposed to in that mode.

I agree that you must have a wiring issue that needs to be sorted...

Rolfe




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