This article explains how to set up a transmiter to wive A fifth channel 3 way movement for e.g. the Graupner SXM electronic switch.

A bit of background

The Graupner SXM is a 4 way switch module which provides 4 outputs that switch to ground. Which output is affected is determined by the location of a channel and the time it is there for. Normally the channel needs to be at the zero (mid point).

As indicated above these switches have 4 channels channels 1 and 2 are controlled by either a short ( less than .75 of a second) move of the channel to 100% ( ch 1) or a long (more than .75 of a second) one for ch2. ch's 3 and 4 are the same but in the other direction. These switches will switch up to 4 amps ( whach I am sure we do not need but means you can run a motor from one) they take the battery negative and switch it 4 ways. the load has to return to the battery +ve. - no problem thats just a wire!

The Set Up

So we have used up all the available stick channels and that just leaves us with switches and they are 2 way ( the DX6e, 6 and up have 3 way switches so you don't need this work around).

We have two switchable channels ch5 which is the (landing) gear channel and 6 which is the flaps. The on/off position of the servo can be adjusted in the tx set up but wee still need 3 ways! up - off - down! to work the 4 way switch though as this will only make two of them work we need a bit of a work around. Luckily the DX6i tx has mix functions Mix 1 and Mix 2. The aero guys use them for flapperons and things. We can use them to get the 3 positions.

On to the set up

We will start with flaps on Ch 6, plug a servo in the RX to check it and turn everything on. Use the selctor roller to move down the set up list to flaps. You will find 4 settings for flaps (1st col) and elevator (second col - do not set this) set the flaps norm to up 100 (little arrow to the left of the column) set the flaps land to down 100 (again little arrow to the left goes up to down as you scroll.

Now go to Mix 1.

Set the first box to flap and then the second box ( after the right arrow) to flap and the INH to ACT (click on the boxes and scroll ).
Make sure or set the Rate D to 0% and the U to -100%

Set the SW to Mix and on mine I set trim to ACT ( not sure you need this).

Now with a combination of the flaps and mix switch you have 3 settings on ch 6 - full up, centre and full down.

You can do the same for Ch 5 and the Gear sw except set the rate D to -100%. I used the Ail D/R switch to mix with it as I used the rudder D/R switch to enable the extra throws needed for the MFCU extra functions.