HS34 Question - what does it do?

[DougN]

I know that sounds really ignorant, but my question is this: does the HS34 translate between formats and msgs, or does it just pass like to like as a cross-switch? I'm trying to decide what functionality i actually get. For example, what does the "Bearing source" button actually do?

I take it that the heading dial changes the heading bug. But is that it? Is that chosen heading rendered in some form that is consumable by an external device?

I assume the course dial interacts with the OBS on the SL30 - when in NAV mode.

I'm trying to make IFR flying a bit easier (too much button pushing and hidden states and choices). I suspect that the HS34 can help; but I'm trying to figure out what the changes would actually be in practice.

My panel consists of an EFIS D100, an EMS D10a, a TruTrak a/p, an AvMap EKP-IV GPS, a SL30, GPS150XL, and a GTX327.

Thanks one and all for any insight you can provide.

 

[DougN]

Let me try a specific question. Currently I drive my TruTrak a/p from the Garmin GPS 155XL using the 429 interface.

The GPS 155XL will accept a course/heading input from an ARINC 429 device.

Assume my EFIS D100 is connected to an HS34 (DSAB), and the HS34 is connected to the ARINC 429 input of the GPS 155XL from one of its 429 outputs.

If I set the heading bug on the EFIS D100 (which currently does nothing but sets the bug), will that flow through the system such that I can drive the autopilot through that chain (HSI hdg set -> HS34 -> GPS -> A/P)? (assuming that the autopilot is in GPS NAV mode).

 

[PhantomPholly]

I haven't had any luck with that using a GNS 480. I THINK it is because the GPS itself doesn't have any such function as "fly this track."

Using the same 429 lines, when in NAV mode with my 480 the course setting bug DOES turn the HSI, and the course deviator functions. But it does nothing in GPS mode except rotate the HSI dial unless there is actually a course (direct or part of a flight plan) active on the GPS - in which case the course knob is disabled.

So I think the answer is, "it is working as designed."

 

[khorton]

I haven't had any luck with that using a GNS 480.  I THINK it is because the GPS itself doesn't have any such function as "fly this track."

Using the same 429 lines, when in NAV mode with my 480 the course setting bug DOES turn the HSI, and the course deviator functions.  But it does nothing in GPS mode except rotate the HSI dial unless there is actually a course (direct or part of a flight plan) active on the GPS - in which case the course knob is disabled.

So I think the answer is, "it is working as designed."

What happens if you put the 480 in OBS mode?  On some other GPSs, the HSI course gets fed back to the GPS if it is in OBS mode.  I'm pretty sure that mode is required by the TSO, so it should be there.

 

[dynonsupport]

a bunch of answers strung together....

I know that sounds really ignorant, but my question is this: does the HS34 translate between formats and msgs, or does it just pass like to like as a cross-switch? I'm trying to decide what functionality i actually get. For example, what does the "Bearing source" button actually do?

It does not translate format or messages or pass along data, with one exception. I'll get to that in a minute.

In a nutshell, the HS34 has ARINC inputs and outputs for getting data from / sending data to devices like the 430, and has serial ports for receiving GPS data and sending/receiving data from SL30 nav/comms. And the knobs and button are simply for what is displayed on the Dynon HSI. They do not control the flow of data.

In particular, the bearing source button cycles through each of the available two bearing source windows, which when highlighted can then be set to any bearing that is currently being received by any device. So if you have a 430 and a 496, you could select any of the primary NAV bearing to station (when tuned to a VOR), the bearing to the NAV standby station (when the standby freq. is a valid VOR), the bearing to your 430 GPS waypoint (when there is one), or the bearing to your 496 waypoint (ditto).

The one case where the HS34 passes along information is from a Garmin GPS to an SL30. This lets the GPS push frequencies to the SL30 like it normally would if those devices were directly connected. If we didn't pass that data along, you'd basically be giving up that feature when you pass everything through the HS34.

I take it that the heading dial changes the heading bug. But is that it? Is that chosen heading rendered in some form that is consumable by an external device?

Yep, that's it. Though the heading bug, in turn, can also drive the Dynon Autopilot's heading goal (and only the Dynon Autopilot, not any others). Here is a list of the data that is outputted by the HS34's ARINC transmitter: http://wiki.dynonavionics.com/Generic_ARINC-429_Wiring

I assume the course dial interacts with the OBS on the SL30 - when in NAV mode.

Also correct. It also sends the OBS to anything that can receive it, like the 430 in NAV mode, or the 430 in GPS OBS hold mode.

On some other GPSs, the HSI course gets fed back to the FMS if it is in OBS mode.  I'm pretty sure that mode is required by the TSO, so it should be there.

We do send out OBS over ARINC, per http://wiki.dynonavionics.com/Generic_ARINC-429_Wiring, which is used just as you describe, at least on a 430 and similar, when you have the unit set up

 

[dynonsupport]

The GPS 155XL will accept a course/heading input from an ARINC 429 device.

We can send it course, but it may not do anything with it, except when in an OBS hold mode (like the 430, but I don't know off the top of my head if the 155 supports this)

Assume my EFIS D100 is connected to an HS34 (DSAB), and the HS34 is connected to the ARINC 429 input of the GPS 155XL from one of its 429 outputs.

If I set the heading bug on the EFIS D100 (which currently does nothing but sets the bug), will that flow through the system such that I can drive the autopilot through that chain (HSI hdg set -> HS34 -> GPS -> A/P)? (assuming that the autopilot is in GPS NAV mode).

Because the heading bug is not currently sent out over ARINC, no. But also, even if we did, your other autopilot probably doesn't accept heading bug setting via an ARINC heading bug setting. A question for your autopilot manufacturer is whether or not an external heading command can be received at all. Last we checked, on the popular models, the answer was no, which was one reason we didn't end up sending out the heading bug ARINC label.

 

[PhantomPholly]

I haven't had any luck with that using a GNS 480.  I THINK it is because the GPS itself doesn't have any such function as "fly this track."

Using the same 429 lines, when in NAV mode with my 480 the course setting bug DOES turn the HSI, and the course deviator functions.  But it does nothing in GPS mode except rotate the HSI dial unless there is actually a course (direct or part of a flight plan) active on the GPS - in which case the course knob is disabled.

So I think the answer is, "it is working as designed."

What happens if you put the 480 in OBS mode?  On some other GPSs, the HSI course gets fed back to the GPS if it is in OBS mode.  I'm pretty sure that mode is required by the TSO, so it should be there.

I don't know. The ARINC IN line receives OBS info from the HS34 at all times, but I am unaware if it will perform the function you describe.

I'm still working out bugs after a 20 month refurbishment / upgrades; currently I'm fighting with the oil temp sender which is reporting up to 60 degrees hot when the alternator is running due to a corroded ground stud which penetrates the firewall. Finding the culprit has been a 2 week journey; tomorrow I'll be running a brand-new engine ground cable.