Modulation, Failsafe And Resolution (512 Vs 1024) - FUTABA 9Z WC2 Getting To Know Manual

C. Modulation, FailSafe and Resolution (512 vs. 1024)
My transmitter has a PPM and PCM function. Which function should I use and how?
If you have an FM (PPM) receiver, your transmitter must be set on PPM. If you have a PCM receiver,
your transmitter must be set on PCM. To check which type of modulation (also known as pulse mode)
your model memory is currently set for, turn on the transmitter. In the upper right corner, just to the
left of the elapsed timer, you will see either PPM or PCM. If necessary, change, as described below.
Turn the power off and back on to actively transmit in the other Pulse Mode type. Note: Pulse Mode
(PMD) type is selected separately for each model, so, for example, changing from model 1 which is
PCM to model 2 which is FM (PPM) would require you to cycle the transmitter off and back on after
making the model selection so the radio now transmits in the matching pulse mode.
Change Pulse Mode (PMD)
Type from PPM to PCM, and cycle
power to transmit in the new Pulse
Mode type.
What advantages do I gain by using PCM rather than FM (PPM)? I heard PCM has better range?
And better noise interference rejection? Also, what is FailSafe and how is it related to PCM?
Range and Noise: There is no range increase associated with PCM; however, there is marked
improvement in noise reduction, and in safe performance during noise. Basically, PCM takes your
radio's FM (PPM) signal and codes it. Then the PCM receiver decodes it and utilizes it. Random noise
from other sources are less likely to be mistakenly read as actual servo instructions, which regularly
happens with FM (PPM).
FailSafe: If your PCM receiver detects interference or a loss of signal, it maintains the last task it was
doing until a preset time interval programmed in the radio. If it continuously receives interference
past the preset, the receiver then obeys the commands you set in the transmitter which were
previously transmitted and have been stored, waiting for just such a situation. (For example on giant
scale gas planes we set FailSafe to shut down the kill switch and throttle and leave all other surfaces in
the last commanded position). Battery FailSafe (BFS) is explained in the next question. Please see P. 1-7
for information on combining FailSafe and the PA2 Pilot Assist Tool for even more in-flight protection.
My throttle servo suddenly went to my FailSafe position but all other controls operated normally. I
pulled my throttle stick all the way back and then moved it again, and the throttle worked for a
while, then did it again. Why?
Battery FailSafe (BFS) is an automatic safety function of the 9Z computer radio. When the receiver's
battery voltage drops below a predetermined cut off (approximately 3.8V) and remains there for more
than a set amount of time (several seconds – this allows for occasional hard drains caused by violent
maneuvers such as snaps which immediately returns the voltage back to above 3.8V), the receiver
recognizes that you are in a dangerous condition, and brings your throttle servo to a preset position.
This is a warning that you must safely retrieve the model (meaning land for aircraft/helicopters), as
you are nearing a point where there will not be sufficient voltage to operate the receiver.
An additional aspect of this feature is that you can pull your throttle stick to idle and readvance it,
allowing you to use power to retrieve the model. You will typically have throttle control for
approximately 30 seconds before the feature reactivates, returning the throttle to the preset when this
feature reactivates. IT IS IMPERATIVE THAT YOU LAND OR OTHERWISE RETRIEVE YOUR
MODEL IMMEDIATELY BEFORE LOSING CONTROL OF THE MODEL ALTOGETHER.
Open Pulse Mode (PMD)
Select PCM
Close Function
Cycle Transmitter Power
1-6
P B I
F
N R
power off power on