GRAUPNER MC-22S, Programming Manual

Page: 114 / 180

114 Program description: Special functions
Fail-Safe setting
Fail-safe in the “SPCM20” transmission mode
F A I L S A F E ( S P C M 2 0 )
P o s
h o l d
1 2 3 4 5 6 7 8
This menu appears in the multi-function list only if you
have selected the SPCM20 transmission mode . This
mode of operation must be pre-set in the memory-
specifi c »
Base setup model « menu. The SPCM20
transmission mode can be used with all receivers with
“smc” in the type designation (smc-19, smc-20, smc-
19 DS, smc-20 DS etc.).
Fail-safe programming for the PCM20 mode is discus-
sed in the previous section.
The operational security of Pulse Code Modulati-
on (PCM) is inherently higher than that of simple Pul-
se Position Modulation (PPM), since the receiver in-
corporates an integral micro-processor which detects
whether a received signal is valid, or is incorrect or
garbled due to outside interference. In the latter case
the receiver automatically replaces the invalid signal
with the last received correct signal, which is stored
in the receiver. This time-limited “holding” procedure
suppresses brief interference caused by local drops
in fi eld strength and similar momentary problems,
which otherwise result in the familiar “glitches”.
Caution:
If you use either of the PCM transmission modes
(PCM and SPCM), do make use of the enhanced
safety features, by programming the throttle posi-
tion of glow-powered models to idle and the mo-
tor function of electric-powered models to Stop if
the Fail-Safe is triggered. It is then not so easy for
the pilot to lose all control of the model if interfe-
rence should occur; if this happens with the mo-
del on the ground, serious damage to property
and even personal injury can result.
If you select the SPCM 20 transmission mode but
have not yet carried out the fail-safe programming,
you will see a warning message on the screen when
you switch the transmitter on or switch model memo-
ries. The message remains on-screen in the basic
display for a few seconds:
Model name
#01 0:00h C73
H-J Sandbrunner
9.8V
4:10h
0 0 0 0
Stoppuhr
Flugzeit
0 00
0 00
:
S t o p p u h r
F l u g z e i t
:
If interference affects the radio link between transmit-
ter and receiver, the “Fail-Safe” function determines
the receiver’s behaviour. In SPCM transmission mode
the servos can either:
1. maintain (“hold”) the current position when in-
terference strikes; the servos stay continuously at
the position corresponding to the last valid signal
until the receiver picks up another signal which it
recognises as valid.
2. move to a freely selectable position (“Pos”)
when interference strikes.
In contrast to PCM20 mode the receiver outputs
1 ... 8 can be programmed
individually to “hold”
or “position” mode, without a pre-set delay time.
Receiver outputs 9 and 10 always stay in “hold”
mode.
Use the rotary control to select the channels 1 to 8
(
), and press the rotary control briefl y to switch each
channel between “hold” ( ) and “position” ( ) mode:
F A I L S A F E ( S P C M 2 0 )
P o s
h o l d
1 2 3 4 5 6 7 8
S T O
Use the rotary control to select the STO fi eld. Now
single out all the servos 1 ... 8 which you have set to
Position mode, and move them to the appropriate po-
sitions using the transmitter controls – all servos
si-
multaneously – before briefl y pressing the rotary con-
trol to store the positions as the fail-safe settings. This
data is transmitted to the receiver at regular intervals,
so that the receiver can always revert to them if inter-
ference should strike.
You will briefl y see the following message on the
screen when you store the data:
F A I L S A F E ( S P C M 2 0 )
P o s
h o l d
1 2 3 4 5 6 7 8
P o s i t i o n s t o r e d
S T O
Warning:
Never, ever, switch off the transmitter when you
are fl ying a model – not even for test purposes! If
you do, you run a serious risk of losing the mo-
del, as you will be highly unlikely to be able to re-
activate the RF signal quickly enough, since the
transmitter always responds with the security
query “RF signal on YES / NO” when switched on.
Fail Safe
setup