Spektrum SPMAR12100 - Manual (Page 12)

Spektrum AR12100 21 Spektrum AR12100 22
Your DSM2 equipped 2.4GHz system is intuitive to operate, functioning
nearly identically to FM systems. Following are a few common questions
from customers:
Q: Which do I turn on first, the transmitter or the receiver?
A: It doesn’t matter if the receiver is turned on first, the throttle channel
doesn’t put out a pulse position at this time, preventing the arming
of electronic speed controllers, or in the case of an engine powered
aircraft, the throttle servo remains in its current position. When
the transmitter is then turned on the transmitter scans the 2.4GHz
band and acquires two open channels. Then the receiver that was
previously bound to the transmitter scans the band and finds the
GUID (Globally Unique Identifier code) stored during binding. The
system then connects and operates normally. If the transmitter is
turned on first, the transmitter scans the 2.4GHz band and acquires
two open channels. When the receiver is turned on, the receiver
scans the 2.4GHz band looking for the previously stored GUID.
When it locates the specific GUID code and confirms uncorrupted
repeatable packet information, the system connects and normal
operation takes place. Typically this takes 2 to 6 seconds.
Q: Sometimes the system takes longer to connect and
sometimes it doesn’t connect at all. Why?
A: In order for the system to connect (after the receiver is bound), the
receiver must receive a large number of continuous (one after the
other) uninterrupted perfect packets from the transmitter. This process
is purposely critical of the environment ensuring that it’s safe to
fly when the system does connect. If the transmitter is too close to
the receiver (less than 4 feet) or if the transmitter is located near
metal objects (metal transmitter case, the bed of a truck, the top of
a metal work bench, etc.) connection will take longer. In some cases
connection will not occur as the system is receiving reflected 2.4GHz
energy from itself and is interpreting this as unfriendly noise. Moving
the system away from metal objects or moving the transmitter away
from the receiver and powering the system up again will cause a
connection to occur. This only happens during the initial connection.
Once connected the system is locked, and should a loss of signal
occur (failsafe), the system connects immediately (4ms) when signal
is regained.
Tips on Using 2.4GHz Systems
Q: I’ve heard that the DSM system is less tolerant of low
voltage. Is this correct?
A: All DSM receivers have an operational voltage range of 3.5 to 9.6
volts. With most systems this is not a problem as in fact most servos
cease to operate at around 3.8 volts. When using multiple high-
current draw servos with a single or inadequate battery/power source,
heavy momentary loads can cause the voltage to dip below this
3.5-volt threshold causing the entire system (servos and receiver) to
brown out. When the voltage drops below the low voltage threshold
(3.5 volts), the DSM receiver must reboot (go through the start-up
process of scanning the band and finding the transmitter) and this
can take several seconds.
Q: Sometimes my receiver loses its bind and won’t connect,
requiring rebinding. What happens if the bind is lost in flight?
A: The receiver will never lose its bind unless it’s instructed to.
It’s important to understand that during the binding process the
receiver not only learns the GUID (code) of the transmitter but the
transmitter learns and stores the type of receiver that it’s bound to.
If the transmitter is put into bind mode, the transmitter looks for the
binding protocol signal from a receiver. If no signal is present, the
transmitter no longer has the correct information to connect to a
specific receiver and in essence the transmitter has been “unbound”
from the receiver. We’ve had several DX7 customers that use
transmitter stands or trays that unknowingly depress the bind button
and the system is then turned on losing the necessary information to
allow the connection to take place. We’ve also had DX7 customers
that didn’t fully understand the range test process and pushed the
bind button before turning on the transmitter also causing the system
to “lose its bind.”
If the system fails to connect, one of the following has occurred:
• The transmitter is near conductive material (transmitter case, truck
bed, etc.) and the reflected 2.4GHz energy is preventing the system
from connecting. (See #2 above)
• The transmitter was put into bind mode knowingly (or
unknowlingly) causing the transmitter to no longer recognize
the receiver.
Tips on Using 2.4GHz Systems (continued)