Channel input for copter lost alarm

[duststorm]

I want to use one of these tiny aircraft lost/finder alarms, like http://www.banggood.com/SKYRC-Anti-Lost ... 50884.html
I connect the thing to one of the spare analog pwm channels of my receiver. In the mixer, I tried passing a constant low, half and full pwm value through this channel, but always this alarm ends up sounding while flying.

My guess is that the input needs to vary on this channel for the alarm to stay quiet.
So I am looking to set up some alternating signal on this channel. I found mention in the manual of a servo test pattern that would probably do nicely. But I don't know how to set it up exactly.
Is it correct that I just need to select CH15 as input for that channel, or do I need to enable something else as well?

[jhsa]

Set up a logical switch using a timer.

L1 time OFF 4 ON 4

L1 will be ON for 4 seconds and then OFF for another 4 seconds, and keep repeating it.

Now create a mix on the desired channel.

CH8 100% FULL Switch L1 Slow (u 3 :d 3)
The channel is triggered by the logical switch but it will take 3 seconds to move from one end to the other, and then back..

João

[ReSt]

Did you set the switch to Mode 2 ?
Otherwise the alarm will sound after 1 minute of inactivity (according to the description)

Reinhard

[duststorm]

Set up a logical switch using a timer.

L1 time OFF 4 ON 4

L1 will be ON for 4 seconds and then OFF for another 4 seconds, and keep repeating it.

Now create a mix on the desired channel.

CH8 100% FULL Switch L1 Slow (u 3 :d 3)
The channel is triggered by the logical switch but it will take 3 seconds to move from one end to the other, and then back..

João

Thank you very much! I believe I understand logical switch better now thanks to your hints.
It took me a while to get back to this, as I was pretty much preoccupied with other matters. But I got it to work now!