Multiple D-10a's and HS34 Wiring

[stickshker]

I have 2 D-10A's and I will be using one as a Attitude Indicator and the other as an HSI and using an HS34 to interface with my GNC420 and SL-30. In the event of failure of one D-10A or it's power source I wish to have the remaining unit retain as much of the capability as possible by just switching screens on that unit between Horizon and HSI. It appears that utilizing the HS34 will not a problem during normal ops but I may not get the functionality that I'm looking for when in the above failure modes. I'm looking for suggestions as to how to best utilize the capabilities of all the hardware.

I am also not clear how to get the DSAB connected across the 3 units. Do I wire the HS34 and the slave D-10A to the same pins (DB25 pins 4 and 5) on the master D-10A? Thanks in advance for any forthcoming advice or suggestions.

 

[dynonsupport]

DSAB is a "multi-drop" bus, which means, tie all the DSAB A lines together, all the DSAB B lines together - even though this next part isn't intuitive - everything will be able to talk to each other.

Now, so that everything doesn't talk to each other at the same time, one of your EFIS-D10As needs to act as the "bus master" and control the flow of data.

So in normal operation in your setup, one of the EFIS-D10As is the bus master (this is whichever EFIS you configure the DSAB network from) . If your non-bus master fails, your bus-master can still talk to the HS34, and you will still be able to use that EFIS as your HSI if it wasn't the one you had on the HSI screen already.

If the non-bus master fails, the DSAB network will go away, which means the HS34 too. This can be fixed by reconfiguring the DSAB network from the remaining EFIS, which would turn it into the the bus-master, and bring back the HS34 and HSI functionality. Because this is a configuration step, this is something we would recommend you do on the ground, not in-flight.

 

[stickshker]

Thanks, I think I've got it now.