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GI 275 and KFC150 - attitude source?


elimansour

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26 minutes ago, OZMOONEYMAN said:

Hi PTK,

Reading this thread.  Q) would the GI275 output altitude info to KFC150 autopilot to allow altitude capture / alt preselect ?  I assume G5 most will not.  Thanks

No it cannot.

In the KFC150 system, the KAS297B is what handles the altitude capture/preselect and the inputs it needs are baro correction and gray code in the pre-RS232 format. These are provided by the KEA130A encoding altimeter. The 275 can provide both of these, but not in a format the KAS297B can understand -- the gray code is in RS232 and the baro correction is in a 2 wire hi/lo setup vs the KEA130's 3 wire excitation/reference/sense method.

The gray code is easy to work around with a blind encoder if you want a standard altimeter; however, the baro correction is only offered by the KEA130A.

KFC150 Flight Control System.JPG

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Just now, smwash02 said:

No it cannot.

In the KFC150 system, the KAS297B is what handles the altitude capture/preselect and the inputs it needs are baro correction and gray code in the pre-RS232 format. These are provided by the KEA130A encoding altimeter. The 275 can provide both of these, but not in a format the KAS297B can understand -- the gray code is in RS232 and the baro correction is in a 2 wire hi/lo setup vs the KEA130's 3 wire excitation/reference/sense method.

The gray code is easy to work around with a blind encoder if you want a standard altimeter; however, the baro correction is only offered by the KEA130A.

KFC150 Flight Control System.JPG

Copy thanks for the great reply.  I guess a KEA130A encoding altimeter functioning as a standby could be used to achieve this with a G3X concurrent install.  But cost of a KEA130A does look pricey.  It would need to be calibrated per a schedule for IFR also.  Come on Dynon Cert with your A/P.

 

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37 minutes ago, OZMOONEYMAN said:

Copy thanks for the great reply.  I guess a KEA130A encoding altimeter functioning as a standby could be used to achieve this with a G3X concurrent install.  But cost of a KEA130A does look pricey.  It would need to be calibrated per a schedule for IFR also.  Come on Dynon Cert with your A/P.

 

Do you not have a working KAP297B today? I was poking through the Beechtalk thread posted above and it's said there that the 275 can emulate the 130 and drive the preselect module. The GAD43e actually calls this KEA130 emulation out explicitly.

I am getting two 275s installed in about 3 weeks and my installer has called multiple times about this exactly situation and been told varying versions of 'no'. The pins on the GAD43e are labeled as out and ground vs the 275's hi (out) and lo (in). So it is possible this will work after all and Garmin just isn't up to speed on the product, still.

Once mine is installed, I'll report back.

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Just now, smwash02 said:

Do you not have a working KAP297B today? I was poking through the Beechtalk thread posted above and it's said there that the 275 can emulate the 130 and drive the preselect module. The GAD43e actually calls this KEA130 emulation out explicitly.

I am getting two 275s installed in about 3 weeks and my installer has called multiple times about this exactly situation and been told varying versions of 'no'. The pins on the GAD43e are labeled as out and ground vs the 275's hi (out) and lo (in). So it is possible this will work after all and Garmin just isn't up to speed on the product, still.

Once mine is installed, I'll report back.

Great stuff.  Report will be greatly received

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To my knowledge the answer is no as a standalone pre-selector option.  The KAS-297B used baro correction, gray code, and part of the frequency oscillator in the KC191/192 to produce a summed pitch command for VS modes.  You can refer to the GAD43E for additional information if needed.  With the dual GI275 we did in a M20J with a KFC 200 there was no pre-selector function added with the install of the GI-275.

If you currently have a KAS-297B you might be able to use the 275 for baro correction but would still need gray code from some other source. A blind encoder should work if you did not want the KEA-130.  Also, you must do the calibration with the KAS-279B when changing the encoder/baro source.

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