2
Installing the FS Receiver
Tip:
Servos, aileron extension cables, switch harnesses, Y-harnesses, battery packs, chargers and
many other accessories are available from your local FMA dealer or from FMA Direct (www.fma.com).
1. Plug in crystal and servos. Servo chan-
nel 1 is farthest from crystal. Black or
brown wires on connectors go toward
outside. Plug battery/switch harness
into any unused channel, or use Y har-
ness to connect battery and servo to one
channel. (
Do not use “old style,” pre-
“Z-type” Airtronics servo connectors.
)
Failure to observe correct servo/
battery polarity voids warranty.
Damage may result to both receiver and servos.
2.
Optional, but recommended:
External Switch/LED Module (part number FSRES1, available
separately) lets you interact with receiver from outside aircraft. Mount module in holes in
fuselage, then plug it into receiver on pins between button and crystal (white wire toward servo
connectors).
3. Wrap receiver in foam rubber and secure in aircraft.
Failure to protect receiver voids war-
ranty.
4. Route antenna. Do not coil antenna, as this substantially reduces range. You may cut antenna
to as short as 18" without de-tuning the receiver. However, range will be reduced. Be sure to
range test and cut off a little bit at a time until antenna reaches desired length.
About the FS Receiver
How it works.
Unlike most receivers, when the FS Receiver detects bad frames, it moves the
servos to the last known position or moves them to failsafe positions you preset, depending on the
mode you set for each channel.
FS Receiver Error Detection
learns about the transmitter sending
signals to the receiver. It determines the transmitter type (positive or negative shift) and number
of channels. When the receiver detects bad frames for about 1 second, it takes over control of the
servos. This is called a
failsafe
.
The FS Receiver has extensive error correcting ability to clean up the PPM signal. Additionally,
the receiver continuously performs 20 internal checks for memory and I/O problems. After low
voltage brownouts, it restores operating parameters without locking up.
Modes:
In
Last Frame Hold Mode
, the FS Receiver maintains the servo positions in the last valid
frame from the transmitter. As delivered from the factory, all channels are set to Last Frame
Hold Mode. You can also reset the receiver to this state at any time.
In
Failsafe Mode
, loss of valid frames (for about 1 second) moves some or all the servos to
positions you preset: all channels with failsafe positions move to their preset positions, while
channels without failsafe positions stay where they are (as in Last Frame Hold Mode).
In
Setup Mode
, you tell the FS Receiver what to do when it receives bad frames. You can set
any channel to move to a preset position during Failsafe Mode. Channels not set up for Fail-
safe Mode remain in Last Frame Hold Mode. The receiver stores setup information, and keeps
it even when power is turned off.
Normal Flight Mode
is the receiver’s regular operating mode. Use Normal Flight Mode for
testing, range checking and flying your aircraft. If the receiver detects invalid frames, it auto-
matically applies Last Frame Hold or Failsafe presets to each channel. When valid frames are
again received, the FS Receiver returns to Normal Flight Mode.
FS Receiver
Pin 1 (black or brown)
Channel 1
LED Button
Crystal socket White
Connect Ext. Switch/LED Module here
Red wire
Antenna
3
Setting up and using the FS Receiver
Setting up the receiver
1. Enter Setup Mode: Turn on transmitter,
press and hold receiver button while turning on re-
ceiver
. LED “twinkles” in Setup Mode. Servos set for Last Frame Mode move slowly, servos
set for Failsafe Mode move to failsafe positions (and don't move after that).
2. Set a channel for Failsafe Mode: Move transmitter stick to desired failsafe position, press
receiver button, return stick to neutral (or idle) before LED turns on. Repeat for other chan-
nels. Channels in a mix are set at the same time. If not set for Failsafe Mode, channel is auto-
matically in Last Frame Hold Mode.
Best failsafe preset servo positions depend on your particular aircraft and how it behaves in the
air. A reasonable starting point for flight-stable, non-aerobatic airplanes is:
Ailerons: neutral.
Rudder: moderate right turn.
Elevator: neutral.
Throttle: 1/3 to 1/2.
Test these settings and adjust them as needed. Goal is to have plane circle and gently descend,
without stalling, during a failsafe condition.
3. Leave Setup Mode: Turn receiver off. Receiver retains settings even when power is off.
Checking radio system range: initial test and troubleshooting procedure
(Because the FS Receiver corrects for occasional glitches, you can't check range by watching for
jittering servos or control surfaces.)
1. Place receiver on a non-metallic surface (e.g., cardboard box) to elevate it about 2 feet (60cm)
off the ground. Fully extend receiver antenna and position it vertically above receiver (tape
antenna to a wooden dowel, for example). Connect one servo to receiver channel 1.
2. Fully collapse transmitter antenna. Turn on transmitter.
3. Connect a battery pack directly to receiver. Do not use a switch harness for this test, since a
switch harness may reduce range.
4. Walk away from receiver about 200 feet (60m) while moving channel 1 transmitter stick.
5. KEEPING TRANSMITTER ON, return to model and watch
receiver LED:
If LED is still continuously on: there were no failures, and the
receiver remained under your control during the range test.
If LED is blinking, range is less than 200 feet (60m).
6. Disconnect receiver from battery, then turn off transmitter.
Checking failsafe operation on the ground
1. Turn on transmitter, turn on receiver.
2. Turn off transmitter. Receiver moves servos to failsafe/last frame positions.
3. Turn on transmitter. Receiver LED blinks, indicating a failsafe occurred.
Using the receiver
To check for interference:
Turn on receiver (leave your transmitter off). LED is on for 2 sec-
onds to confirm power, then: LED off = no interference, or blinking = interference is present.
To check battery voltage:
While moving transmitter sticks (to load system), press receiver
button 1 time, then count LED blinks (long blink = 1 volt, short blink = 0.1 volt).
Fly normally. If receiver loses signal, servos go to failsafe presets or stay at last good position.
Optional:
After flight, keep transmitter and receiver on to review radio system performance:
If LED is blinking, number of blinks = number of failsafes during flight.
Press receiver button 3 times, count LED blinks to determine number of bad frames during
flight (long blink = 10 frames, short blink = 1 frame). Less than 30 bad frames = very clean
signal during flight. (Use Viewer Software Help Wizard after flight for more receiver data.)
Note:
If, under these conditions, the
radio system experiences failures,
there may be a problem with the
transmitter, the FS Receiver or
another part of the radio system. If
you suspect the transmitter is out of
tune, FMA can tune it for you. With
proof of purchase for an FMA
receiver, FMA will tune your transmit-
ter (any brand) at no charge. The
only cost is for shipping.
