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VOR/LOC/GS setup for GTN to KI-525a

Sandel were a lot later than the 1980s, and their old 3308 was late-1990s IIRC. The SN3500 came out after that – my panel

It was only with the Aspen that you got a significantly cheaper route to the functionality, but they had a lot of problems in the early years. A friend of mine is on his 4th one. Sandel is a high grade product, not cheap, and they sell a lot into the turbine heli market, and to the military. The SN3500 is the most sunlight readable instrument in my panel.

Administrator
Shoreham EGKA, United Kingdom

Hence, the emergence of the EHSI in GA with Sandel leading in the 80s – 90s and of course Garmin and Aspen taking over in 2K

FAA A&P/IA
LFPN

The KI525 is the most modern HSI in common GA use but it dates back to around 1978

What are you trying to imply? That there were no standards in the 70ies?

LSZK, Switzerland

Isn’t the full deflection voltage supposed to be standardized?

You would hope so but this technology goes back decades.

The KI525 is the most modern HSI in common GA use but it dates back to around 1978. The user manual which came with the TB20 in 2002 was dated 1980. The latest MM is 2002. Other HSIs are much older.

Administrator
Shoreham EGKA, United Kingdom

Well, that depends. If you have an PFD with HSI suchs as the Aspen EFD1000 Pro then you will use ARINC 429. On older products you will typically use analog signals.

JP-Avionics
EHMZ

Yes, the ARINC429 is not relevant to any HSI in GA use. They are all analog.

Administrator
Shoreham EGKA, United Kingdom

tomjnx is right. Altough often there is an adjustment for alignment purpuses when required. This is basically to match up for component error’s.
Peter is mistaking spirit49 settings with autopilot gain settings. On most systems you can set the autopilot gain setting. This is how the autopilot responds to an error signal. If the autopilot gets of track it must correct with a certain amount, this amount is set using these gain settings. To much gain and the autopilot will overshoot and cause oscillations / instability. Not enough gain and the autopilot will undershoot (it won’t make enough correction to stay on track).

JP-Avionics
EHMZ

Peter, the settings you are indicated are completly different.

The GNC, GNS and GTN series can interface with:

- Analog indicators, such as the MD-200, GI-102, GI-106, KI-202, KI-206, KI-525A
- Converter Indicators (composite signals) suchs as the KI-203, KI-204, KI-208, KI-209
- Digital indicators (ARINC signals) such as Aspen EFD1000, Avidyne EX500 and EX5000

The Arinc setting of spirit49 is the NAV ARINC 429 output. This bus is used a two different speeds, hence the selection to select the correct speed. On SDI it will transmit a label from which unit the data is from. On common the SDI = 0, On VOR/ILS1, SDI = 1 (Pilot) and on VOR/ILS, SDI = 2 (Co-pilot).
The GNC, GNS or GTN will respond to data received for SDI 0 and for SDI 1 or 2 depending on settings. On all data transmitted onto the bus it is clear to all equipment from which equipment (pilot or copilot) the data is being received.

JP-Avionics
EHMZ

Isn’t the full deflection voltage supposed to be standardized? So why do you need to adjust it?

Don’t know about the GTN, but my previous GPS only had a gain setting until they fixed the drive circuitry

LSZK, Switzerland

I don’t know the GTN650 but in say the Sandel SN3500 EHSI, which can emulate the KI525 for the purpose of driving an analog autopilot, the config involves specifying the HSI to be emulated by its name (from a pulldown menu of different HSI types) and that automatically sets up the right gain.

There is an additional parameter where you can tweak the output but normally that isn’t needed.

For driving different HSIs, the GTN650 must have a “gain” setting so the right full-scale voltage can be output for the lateral and vertical deviations.

Administrator
Shoreham EGKA, United Kingdom
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