I recently connected my GNS430 to to my EMS, and thence to my EFIS-D10. I can interchange screens between the two instruments as advertised. When I have an active waypoint entered and get the additional HSI functionality on the DG, I notice that the TAS displayed on the HSI screen is consistently 10 knots slower than the TAS displayed simultaneously on my EFIS screen. I have also seen the EFIS displaying a headwind (with no velocity number), while the HSI shows (correctly) that the wind is off of the tail. The EFIS TAS seems more reasonable, but it is unclear which is correct. I have the OAT probe on the EFIS, but not on the EMS, and the GPS is set to magnetic bearings. Any insight or suggestions? I assumed (perhaps incorrectly) that the HSI would be getting the TAS from the EFIS, so the two should match.
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EFIS / HSI display TAS differences
- Thread starter spayne
- Start date
- Joined
- Mar 23, 2005
- Messages
- 13,226
A few questions:
Are both units on 4.0, with DSAB setup?
Is there more than one OAT physically installed? (there need not be). If not, make sure that the device that doesn't have an OAT connected doesn't have one setup in the setup. This can be found under EMS>SETUP>SENSORS then GP1, 2, or 3 for the EMS, or under EFIS>SETUP>OAT on the EFIS. Only one of them should have an OAT defined and setup.
Are both units on 4.0, with DSAB setup?
Is there more than one OAT physically installed? (there need not be). If not, make sure that the device that doesn't have an OAT connected doesn't have one setup in the setup. This can be found under EMS>SETUP>SENSORS then GP1, 2, or 3 for the EMS, or under EFIS>SETUP>OAT on the EFIS. Only one of them should have an OAT defined and setup.
Thanks for the suggestions.
As for the connections:
GNS430 to DMS-D10
DSAB connected between the DMS-D10 and the EFIS-D10A
RS-232 connected between the DMS-D10 and the EFIS-D10A
OAT probe on the EFIS-D10A only
The EFIS and HSI screens are in the EMS-D10 screen rotation and the engine monitor is in the EFIS screen rotation, and all works fine.
The first GP input on the EMS was enabled to OAT. I switched it to unused. As a result all TAS, ground speed, and wind information disappeared from the HSI screen when I had it displayed on the EMS, which is where I usually display the HSI. I did not think to try displaying the HSI screen on the EFIS, but I do remember that it was displaying TAS on the EFIS HSI screen during taxi. The EFIS is set to display OAT and TAS, which it does when it is on the EFIS screen. I have never checked to see if it is there when the EFIS is displayed on the EMS screen.
Firmware versions on both instruments is 3.0.0
Would changing to 4.0 help anything? With the OAT probe on the EFIS only are there limitations on what data can be displayed on what screen, i.e. true airspeed can only be displayed on the EFIS-D10A screen and that information is not shared with the EMS even when displaying EFIS generated screens? If that is the case, what does the EMS fuel computation take into account without access to OAT?
As for the connections:
GNS430 to DMS-D10
DSAB connected between the DMS-D10 and the EFIS-D10A
RS-232 connected between the DMS-D10 and the EFIS-D10A
OAT probe on the EFIS-D10A only
The EFIS and HSI screens are in the EMS-D10 screen rotation and the engine monitor is in the EFIS screen rotation, and all works fine.
The first GP input on the EMS was enabled to OAT. I switched it to unused. As a result all TAS, ground speed, and wind information disappeared from the HSI screen when I had it displayed on the EMS, which is where I usually display the HSI. I did not think to try displaying the HSI screen on the EFIS, but I do remember that it was displaying TAS on the EFIS HSI screen during taxi. The EFIS is set to display OAT and TAS, which it does when it is on the EFIS screen. I have never checked to see if it is there when the EFIS is displayed on the EMS screen.
Firmware versions on both instruments is 3.0.0
Would changing to 4.0 help anything? With the OAT probe on the EFIS only are there limitations on what data can be displayed on what screen, i.e. true airspeed can only be displayed on the EFIS-D10A screen and that information is not shared with the EMS even when displaying EFIS generated screens? If that is the case, what does the EMS fuel computation take into account without access to OAT?
- Joined
- Mar 23, 2005
- Messages
- 13,226
You need to run Firmware 4.0 to show all of that on the EMS. It will then display the same on both units.