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300XL sequence switch stuck on hold!!!

D

dwilson

Well Known Member
I am grasping at straws and would appreciate any help anyone can offer.

RV9A IFR panel with 300XL, annunciator (MD41-1444), Dual GRT Horizon 1's, SL-30.

Hooked it all up through Approach Fast Stack system.

The 300XL senses the hold button on the annunciator as always on hold, no matter how the switch is cycled.

I have sent the unit back to Garmin TWICE now and it still senses the hold button depressed.

I can't figure out what to do next.

Any ideas would be appreciated.

Thanks,
Duane
 
Sequence switch

dwilson said:
I am grasping at straws and would appreciate any help anyone can offer.

RV9A IFR panel with 300XL, annunciator (MD41-1444), Dual GRT Horizon 1's, SL-30.

Hooked it all up through Approach Fast Stack system.

The 300XL senses the hold button on the annunciator as always on hold, no matter how the switch is cycled.


Thanks,
Duane
Click to expand...

Hi Duane

You have not told us if you have an external VOR/GPS indicator.

We are getting ready to wire up my 300XL and my avionics tech is currently checking into the sequence switch on my installation. We are using an MD-40 indicator and inexpensive lighted push button switchs instead of the MD-41. Here is what what I know from a rough diagram I have on my desk.

The sequence switch either grounds or opens ground (not sure yet) to pin 13 on the 300 XL to activate HOLD and the OBS. At the same time power is applied to light the switch and/or hold annunciator.

My guess, one of two areas, (1) the sequence switch itself is not working or it is not wired correctly (2) the GRT setup page has a setting for external or internal course selection for it's VOR or GPS HSI page, this may be set up incorrectly.
 
George in Langley BC said:
Hi Duane

You have not told us if you have an external VOR/GPS indicator.

I do not have an external VOR/GPS indicator. Do I need one or can I use the Horizon 1 for my indicator?


I have not checked the config. for the external nav in the setup menu on the GRT.

Thanks for your input,

Duane
Click to expand...
 
Sequence Switch

dwilson said:
George in Langley BC said:
Hi Duane

I do not have an external VOR/GPS indicator. Do I need one or can I use the Horizon 1 for my indicator?


I have not checked the config. for the external nav in the setup menu on the GRT.

Duane
Click to expand...

Hi Duane

I do not know if you need an external indicator, you will need more expertice than I can provide. I know that the GRT can provide the HSI function but I do not know how or if the GRT can work with and/or recognize the Sequence and Approach switches on the MD-41.

Here is my guess and only a guess. Annunciator switches are hard wired to the GPS, therefore the switch positions would have to be in the GPS data stream (RS232) to the GRT for the GRT to recognize them. Then the GRT would have to act on the commands to activate/deactivate the OBS plus provide a feedback output command to activate/deactivate the annunciator lights on the MD-41.

All very trickey, but it may be possible, the GRT can use an internal or external OBS source but I do not think it can recognize the changed requirement introduced by the Sequence switch. There also may be a conflict with the SL-30 and its OBS requirements. Try setting the GRT setup so that the SL-30 is set to external (OBS) resolver. Then you would set VOR radials on the SL-30 face (also might require change in SL-30 setup page). Let us know the outcome.

My setup is still under study, I plan on using a 2 1/4 inch MD-40 indicator for the GPS OBS source and the GRT Sport will act as OBS source for my SL-30.
Click to expand...
 
This is very interesting as I am planning very much the same configuration as Duane's. I expect a call to GRT would clear determine if George's idea is right.
 
Hi Duane,


I have talked the GRT folks about using the setup that you have for my panel. My understanding is that the GRT can be used with the 300xl and the sl30 without the annunciator. I do not see why having an annunciator would cause a problem, but maybe removing the annunciator from your panel would help solve this. What have the folks at GRT said?

Please keep us posted.
 
For actual operation, I don't believe that the annunciator panel is necessary with the GRT setup, but the 300XL is not IFR certified without it so techniaclly it should be installed for IFR use.
 
ptrotter said:
For actual operation, I don't believe that the annunciator panel is necessary with the GRT setup, but the 300XL is not IFR certified without it so techniaclly it should be installed for IFR use.
Click to expand...

To expand on what Paul states above. The 300XL requires 2 (external) switches, Waypoint Sequencing and GPS Approach, plus five annunciator lights (message/waypoint arrival/waypoint hold/approach armed/approach active) to meet the TSO for IFR certification.

The GRT- 300XL combination is fine for VFR operations however I do not see how I can meet the IFR requirements without additional equipment. In my case an external indicator plus two lighted push button switches switches plus annunciator lights.

The requirements for these switches and annunciators do not seem obvious until you analyze situations such as (1) de-activating an approach for vectors (overtaking traffic etc) and then wanting to re-activate the approach
(2) de-activate the approach for a missed approach and then needing to put the missed approach waypoint on Hold plus enter a published inbound track.

I don't know what the capabilities of the higher end GRT's as I just have the single screen Sport with map option but suspect they are similar.
 
George in Langley BC said:
We are using an MD-40 indicator and inexpensive lighted push button switchs instead of the MD-41. Here is what what I know from a rough diagram I have on my desk.
Click to expand...
George, Thank you for the information about needing the annunciator. I checked with GRT, and I do need to have the annunciator lights and switches to have the 300xl IFR. I see that you are wiring up your own annunciator. Can you post or email me how you did this. Do you have a wiring diagram?

Thanks,

Jonathan
jonathan.cook (at) symech.com
 
Found my answer.

I have enjoyed the great discussion about what we need to use the 300XL with or without the annunciator. I believe that I need the annunciator to be legal for IFR GPS on the 300.

My initial question problem was the 300XL sensing the annunciator hold button being depressed no matter what the hold button was really set on.

After much consultation with Garmin, GRT and Tim at Approach Fast Stack I found the answer!
GRT suggests that the "Hold low" line from the annunciator go to both the GPS and the analog 4 input to the Horizon 1. (pin 18 of the B connector on the horizon.)

That is the way that Tim set up my Approach hub.

However, the hold line goes low any time the GRT connection is made, so I just disconnected the wire from the Approach Fast Stack to pin 18 of the B connector on the GRT.
Now the Hold button on the annunciator switches the 300XL as it should.

According to Carlos at GRT, the only reason to send the Hold low signal to the
GTR Horizon is to alert the pilot of a Hold setting.
I can see the annunciator right above the Horizon and it will tell me when the Hold button is pushed.

I have nothing but praise for all three companies. They worked with me diligently and kindly to figure out this problem.

Duane
 
Great information Duane. I'll remember this when I hook up mine. One thing I like about GRT is you can talk to someone who actually understands their product and is willing to figure out problems like this.
 
JonathanCook said:
George, Thank you for the information about needing the annunciator. I checked with GRT, and I do need to have the annunciator lights and switches to have the 300xl IFR. I see that you are wiring up your own annunciator. Can you post or email me how you did this. Do you have a wiring diagram?
------------------------------------------------------
Sorry no diagram, just hand drawn notes and 300XL etc wiring diagrams.

Square lighted push button switches SPST, On-Off alternate acting, 6 amp @ 24 Volts. Package has trade name Philmore (LKG Industries, Rockford, Il) P/N 30-14514. Use # 386 bulb for 14 Volts. Face cover is removeable and different colour filters installed to change colour, reverse printing on label maker allows switch label inside the clear cover. Cannot figure out how to insert picture.
Click to expand...
 
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