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AP Servo Wiring Questions

PilotBrent

Well Known Member
I'm installing the wiring in finish kit section 31B and I have three questions for the experienced builders ahead of me (that might be embarrassing). Maybe I can't see the fuselage for all the aluminum.

Question 1. Roll servo Section 31B-20. Mentions installation of the black ground lead from pin #9 (step 2) in the molex connector but I can't seem to locate any mention in the plans specifically where the ring terminal is suppose to be attached. Its clearly a screw location, but where exactly?

xc12k5.jpg


Question 2. Similar to above for the pitch servo. I have two grounds, one black lead from the molex connector and one from the noise filter (section 44-04 figure 3). Picture below. Do both get grounded on the same screw on the seat rib (44A-04 figure 3)? Again I don't see any clear mention about grounding both of the ring terminals together.

tam3bb.jpg


Question 3. Most confusing. Both pitch and roll servos have no more than 7 wires coming from them into the molex connectors. But installing the finish kit, it seems the plans have 9 different leads to insert into the molex connector coming from the Skyview wiring harnesses. (eg. for pitch servo 31B-09 figure 2 has 5 wires called out, and 31B-19 figure 3 has 4 more wires to add to the same molex connector) Since the servos only have 7 wires to connect to the molex connector, what is the purpose of these 2 additional wires?:confused:
 
Not sure what brand of A/P you have, but ...

... my Tru-trak has a very complete and detailed wiring diagram that shows where each of the servo wires come from, what they control, and where they terminate. Maybe you could get the same from your A/P supplier?
 
Your Skyview Installation manual section 10 has details about what each wire is for. Now, my AP installation - one of the earliest Skyview installations - was of the pre-molex method using the old fuselage wiring harness (which was designed for the D-180 but had "future plans" built in for Skyview) and using standard spade connectors (this was the "old way of doing it, molex is a recent mod both for these connectors and the trim motor.) But there were no leftover wires when connecting it to all up. Note that the same servos also serve D-180 users but the wiring is different. That was probably taken care of in the ADAPTER Harness some of us early Skyview types got for the AP system. Your case may be different if you got a new style or old style fuselage wiring harness. Your best bet is to talk to Vans and post what you find out, also noting your kit number and whether it uses the old or new fuselage harnesses (the "Optional" one.)
 
The more I tried to chase this down in the drawings the confusider it got! Page 44-06 Rev 0 in the older plans shows the noise filter going by itself to the floor rib.

Apparently in the older plans the servos themselves (via their own black wire) were grounded via the wiring harness, not to a local piece of aluminum via ring terminal. I'd have to open up Sweetie to verify but I am pretty sure of that.

Note that Section 31B, I do not have, It must be for the revised fuselage wiring harness that is originally designed for Skyview. I bet you similarly do not have Section 42D, which was sent to us "Skyview Adapters." Everybody note - it's getting pretty complicated keeping track!

Page 44-04 Rev 1? Shows the servo hookups, all 7 wires.

As coming from the servo:
White/Blue and White/Green are Skyview Network Wires.
The solid green and solid blue are also Skyview Network wires.
Red is power, Black is ground, Yellow is AP disconnect switch.
That is all 7.

According to those wiring diagrams Vans recently issued, "for finish kits issued after 8-25-11", (yours?) both servos get grounded via Pin 8, black wire, to a local ring connector! This is not as was done on earlier -12s and I am not sure that the drawing is accurate compared to the actual harness. You can confirm. Any hole in a nearby rib with the wire having no chance of interference with a moving part (and with the ability to "undo" it later!) should work. Typically an AN515-8R8 screw, 832P washer, and AN365-832A nut are used.

In that drawing, on the PITCH servo there are 2 "extra" wires in the harness going to the servo molex, shown as not connecting to anything from the servo. These are pin 2 (white wire) and pin 8 (gray-purple).

In that same drawing, on the ROLL servo there is only ONE "extra" wire in the harness going to the servo molex, shown as not connecting to anything form the servo. This is pin 8 (color not labeled by appears to be black-gray?).

What do you actually have?

Extra Wire Purpose? Maybe for some future Dynon Servo with more capabilities?
 
Update from Van's

Got a short note back from Ken Scott. Attach these grounds to local airframe (but no specific step in plans or location is defined which still seems odd for us E-LSA compliant builders). And yes, the extra wires are for "future improvements". So I feel better about not connecting them to anything right now.
 
molex connection....finish kit

Brent, I am facing the same problem wiring the "Headset Module" on page 31B-17. Three white wires from inside the plane on one connector. Only one white wire required on the outside connector. How do you know which two white wires NOT TO CONNECT TO?
Also, is it me? Or is the Figure 2 pin number diagram incorrect?
 
F696 A/P data line

I have a question about wire F696. That's the A/P data line on Pin 8 of the Molex connector. On the Dynon roll servo the respective pin 8 is not connected. I double checked the wiring instructions. Should be ok. Do I miss anything or does the Dynon servo simply not use that line?
 
I have a question about wire F696. That's the A/P data line on Pin 8 of the Molex connector. On the Dynon roll servo the respective pin 8 is not connected. I double checked the wiring instructions. Should be ok. Do I miss anything or does the Dynon servo simply not use that line?

If you have SkyView, every wire from the servo is used in the system. The Skyview servos only have 7 wires, so if the harness has 8, it would be for a different servo, so would be unused. TruTrak uses 8 wires on the pitch, and 7 on the roll. I don't remember how many Garmin uses.
 
I have a question about wire F696. That's the A/P data line on Pin 8 of the Molex connector. On the Dynon roll servo the respective pin 8 is not connected. I double checked the wiring instructions. Should be ok. Do I miss anything or does the Dynon servo simply not use that line?

You are good. On page 31B-20, the ES-00010 connector has 9 positions. The harness has 8 wires. Seven wires are used by the servo. Wire F696 is for "future use", from my research done recently. I was confused as well. That wire goes in position 8. There will be no corresponding wire in position 8 of the mating ES-00009 connector going to the servo (Sec. 44A-03). There are no wires in position 2.
 
To the OP, section 44A-03, figure 2, shows the correct position for the roll servo earth terminal. Over the page, 44A-04 figure 3, gives the info for the pitch servo earth, and the noise filter placement.
Section 44A is the autopilot servo installation section.
Hope this helps.
Cheers,
DaveH
120485
 
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