Relay with SP FPS issues

[msstahl]

Anybody run their Show Planes Flap Position System off of a relay? I’m trying to run the system off of a ground switch on my Tosten stick grip and it’s not working properly. Using the LY2F-DC12 relay config that Stein recommends when activating via the stick switch, the FPS does not lock in and stops immediately on the extend stroke. I can touch the FPS extend wire to a hot 12v wire and it works as advertised. Wondering if it’s just the relay I’m using or if it’s all relays.

 

[johnbright]

schematic?

Do you have a schematic of what you did?

Are you using two separate SPST momentary buttons on the stick, one for up and one for down? Both switching to ground as you mentioned.

I found Steinair "RELAY-FLAP-Wiring-Schematic-2.pdf", attached, but it doesn't incorporate Showplanes' Flap Positioning System.
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[lr172]

Anybody run their Show Planes Flap Position System off of a relay? I’m trying to run the system off of a ground switch on my Tosten stick grip and it’s not working properly. Using the LY2F-DC12 relay config that Stein recommends when activating via the stick switch, the FPS does not lock in and stops immediately on the extend stroke. I can touch the FPS extend wire to a hot 12v wire and it works as advertised. Wondering if it’s just the relay I’m using or if it’s all relays.

So, putting 12V on the wire makes it work, but you have wired the relay to provide a ground to that same wire? What am I missing here? The wiring doesn't seem to match what is required to make the device work. You need to confirm that the relay is providing the needed 12V to the FPS when you press the stick button. I would disconnect the wires from the FPS and use a meter to see exactly what the relay is doing.

 

[msstahl]

Hopefully the schematic I've attached below helps however I threw it together and you'll have to forgive me for it's crudeness.

The relay system is designed to turn my grounding switch on the stick to a positive 12v signal to the FPS.

As you can see the flap motor power goes through the FPS and the switch / relay system merely sens a signal to the FPS.

Flap retraction works normally as the switch on the stick is held until the flaps have reached full travel upward in which the FPS stops the actuator normally, all good here.

On extension however the FPS is designed for a single click to 10, second momentary click to 20.... However when I give the system a momentary signal via the stick switch the actuator starts to move but stops after I let off of the switch, not when it reaches 10 degrees on the flaps. Furthermore if I take the FPS wire for extension (Blue wire) and momentarily touch it to say pole 4 (12v) the actuator extends and continues to extend until reaching the next flap position.

Neither relay has a diode in place so I added a diode between the coil (7&8) and didn't have any luck. I talked to Bryan at Showplanes and its an issue of how the relay is interacting with the FPS. Curious if anybody has been able to solve this problem of driving the FPS with relay?

 

[lr172]

Hopefully the schematic I've attached below helps however I threw it together and you'll have to forgive me for it's crudeness.

The relay system is designed to turn my grounding switch on the stick to a positive 12v signal to the FPS.

As you can see the flap motor power goes through the FPS and the switch / relay system merely sens a signal to the FPS.

Flap retraction works normally as the switch on the stick is held until the flaps have reached full travel upward in which the FPS stops the actuator normally, all good here.

On extension however the FPS is designed for a single click to 10, second momentary click to 20.... However when I give the system a momentary signal via the stick switch the actuator starts to move but stops after I let off of the switch, not when it reaches 10 degrees on the flaps. Furthermore if I take the FPS wire for extension (Blue wire) and momentarily touch it to say pole 4 (12v) the actuator extends and continues to extend until reaching the next flap position.

Neither relay has a diode in place so I added a diode between the coil (7&8) and didn't have any luck. I talked to Bryan at Showplanes and its an issue of how the relay is interacting with the FPS. Curious if anybody has been able to solve this problem of driving the FPS with relay?

Ok, you have confirmed that application of a brief 12V to the EXTEND lead forces the FPS to work correctly; all good with the FPS unit. The wiring diagram implies that the button press on the stick should do the same. Therefore either the relay or stick button is defective or, and more likely, the wiring on the diagram does not match the ACTUAL wiring. Could possibly venture a guess on what is happening, but best to get in there with a meter and find what is happening on all of the wires, both with button depressed and otherwise. Stein is a good outfit, but work is done by humans and humans make mistakes. Also possible you connected the wrong wires on the stick harness when interfacing to the Stein harness.

Larry

 

[Carl Froehlich]

Micheal,

I don’t understand. Why can’t you dump all your relay stuff and just use the switches on the stick? Can you not wire the stick to control the extend and retract wires? The FPS system control current is small, so whatever switches you have in the stick should be fine.

Perhaps I’m tripping on your “ground switch” comment.

Carl

 

[johnbright]

Hopefully the schematic I've attached below helps...

... I added a diode between the coil (7&8)

I suggest disconnecting the ground wire to pin 2 of the extend relay. Wouldn't hurt to disconnect the ground wire to pin 2 of the retract relay also. These connections are remnants of the Stein schematic without Showplanes FPS where these grounds are power paths for the flap motor.

Alternatively you could open up the sticks and rewire the extend and retract buttons so they don't go to ground but to another wire out of the stick that you connect to B+, no relays required. This is what someone did with a Tosten Military Style grip at the link in post #8. I gather you don't have the military grip but the rewire concept is similar.

The diodes across the relay coils likely extend the life of the stick buttons.

Micheal,

... Why can’t you dump all your relay stuff and just use the switches on the stick?...

Carl

Because the stick buttons go to ground and the Showplanes FPS wants them to go to B+
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[Dad's RV-10]

Micheal,

I don’t understand. Why can’t you dump all your relay stuff and just use the switches on the stick? Can you not wire the stick to control the extend and retract wires? The FPS system control current is small, so whatever switches you have in the stick should be fine.

Perhaps I’m tripping on your “ground switch” comment.

Carl

FAQ #1 on Tosten's site:

Q: Do I need a relay deck?

A: Yes, if you are using a switch to drive a motor. For example, flaps/trim, speed-brakes or smoke.

Here's a post form another VAF member with some information.

 

[johnbright]

FAQ #1 on Tosten's site:

Q: Do I need a relay deck?

A: Yes, if you are using a switch to drive a motor. For example, flaps/trim, speed-brakes or smoke.
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The Showplanes FPS acts as a relay deck.
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[lr172]

The Showplanes FPS acts as a relay deck.
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Yes, but the tosten gangs all the source wires together and therefore the switches all create ground connections when pressed. Because the FPS wants 12V and not a ground to activate extend, a relay is required to get a positive polarity feed to the FPS.

 

[johnbright]

The Showplanes FPS acts as a relay deck.
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Yes, but the tosten gangs all the source wires together and therefore the switches all create ground connections when pressed. Because the FPS wants 12V and not a ground, a relay is required to get a positive polarity feed to the FPS.

Roger that... my point is the Showplanes FPS does not run flap motor current through the pilot-operated switch/buttons.
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[Carl Froehlich]

Yes, but the tosten gangs all the source wires together and therefore the switches all create ground connections when pressed. Because the FPS wants 12V and not a ground to activate extend, a relay is required to get a positive polarity feed to the FPS.

Ok - never used a Tosten grip, only Infinity. It would seem ganging all the switches to only do ground would also be problematic for trim control - unless you are using another old school external relay deck for that as well.

For your install just putting the flap switch on the panel and sidestepping the problem may be easier.

Carl

 

[Mich48041]

Michael Stahl, the problem is the ground wires connected to relay terminals #2.
Remove those ground wires from relay terminals number 2.
What happens is that when you let go of the flap down switch,
the relay drops out and grounds the FPS blue extend wire.
Neither the blue extend wire nor the orange retract wires are supposed to be grounded.
Add dots to schematic wire intersections so readers know that wires are connected.
-
Oops, now I see that John Bright already suggested removing the ground wires in post 7.
Good going John.

 

[msstahl]

Grounds removed from pin 2 and it works as advertised. Appreciate the group wisdom here!

 

[Mich48041]

Don't forget to put diodes across the relay coils, banded end to positive.
Connecting diodes to ground won't help in this circuit.

 

[Pilot135pd]

I have a feeling your problem might be ground related. I have some ground I can send you and just wire it like this

 

[johnbright]

Ok - never used a Tosten grip, only Infinity. It would seem ganging all the switches to only do ground would also be problematic for trim control - unless you are using another old school external relay deck for that as well…

Carl

Not only old school… Dynon AP Panel also for instance.

Grounds removed from pin 2 and it works as advertised. Appreciate the group wisdom here!

Excellent! Thanks for having a schematic.
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