Saturday September 2nd, 2006|
Dynon EMS+EFIS Wiring; Mixture Control; MP
Ok, more work on the EFIS and EMS harnesses. Here are the keep-alive wires going to the battery bus (which is always hot). The keep-alive wires keep the time and settings on the units when the master is off. It also charges the EFIS internal backup battery. It's not necessary to use this functionality for the EFIS since the internal battery will charge when the master is on during normal ops and the battery preserves the settings when the master is off. I figure it makes sense to go ahead and run the keep-alive wire to the bus and if I decide not to use it I'll just pull the fuse.
Ok, kind of jumping around here...I decided to go ahead and run the mixture cable. This is in completely a different place than what's called out in the plans. I just sort of eye-balled (pun intended) it and drilled a hole. The plans are actually for a carbuerator and call out the mixture pass through UNDER the throttle cable. Doesn't work at all for my setup, but I think I nailed the location perfectly. Time will tell.
Ok, jumping around some more, I decided to get the manifold pressure hose connected. This came with the Van's FWF kit, not the Dynon probe kit. There's a nice little nipple fitting that you see the hose connected to in the firewall. Unfortunately the tube Van's provides is too small for the barb on the manifold pressure transducer, so I may end up trashing this fitting or making my own.
Ok, here's a blurry picture of the manifold pressure transducer installed, before I trimmed the tie wrap. I put the transducer on this side to make it easier to rivet that rib and also because I will have an access panel directly over this location. The electrical connector was rather interesting to crimp, and they gave you no extra pins.
The manifold pressure transducer requires 5 volt exitation which is provided by the EMS, but you have to break that wire out to several other transducers, so I stold Checkoway's idea of distributing power using these ring terminal strips. I ran out of the small ring terminals so I couldn't complete the last loop (I will with my next order to SteinAir), but you get the idea.
Ok, hard to see in this blurry picture, but the EMS is now displaying the ambient air pressure, which I confirmed with the METAR at LZU to be pretty close.
Ok, I also upgraded my firmware on both units and wired up the DSAB connection. You can see here that the EMS is displaying the DG using information that it's getting from the EFIS. Dynon currently has in beta testing software that will allow my EMS to run a complete HSI. That will be cool. I just hope that you allow you to display MP and RPM on the HSI screen. That would be awesome for my setup since during cruise the RPM and MP are the primary things you're looking at.
This setup also provides some redundancy in case the screen of the EFIS craps out (not the EFIS itself...just the screen). An astute observer will notice that the EMS is not displaying the info bar information or the altimeter setting.
Ok, here's a closer shot of the EMS displaying the ambient pressure.
Oh yeah...this is interesting. For now, the EMS needs the EFIS's RS-232 stream to display the EFIS's data, so you need a null modem adapter to do this. Well, the RS-232 connections on both units are very simple since they don't utilize RTS/CTS lines, etc, so it's just a matter of reversing the send/receive lines and connecting the grounds together. Dynon promises that with a future firmware this connection will no longer be necessary as they will carry everything both ways over DSAB.
Here you can see that both screens data is completely swapped. This setup gives you so many options. Oh yeah..the DSAB can work with any number of devices, so it's possible that if I wanted I could eventually put another D-10A or a D100 on the right side of the airplane for the passenger.
I would like to see Dynon put out a dumb terminal that simply displays the data of other units.