Spektrum SPMAR10000 - Manual (Page 12)

EN
While your DSM equipped 2.4GHz system is intuitive to operate, functioning nearly
identically to 72MHz systems, following are a few common questions from customers.
1. Q: Which do I turn on first, the transmitter or the receiver?
A: If the receiver is turned on first —all servos except for the throttle will be driven to their
preset failsafe positions set during binding. At this time the throttle channel doesn’t
output a pulse position 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 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 begins transmission, and then when
the receiver is turned on, it scans the 2.4GHz band looking for the previously stored
GUID and 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.
2. Q: Sometimes the system takes longer to connect
and sometimes it doesn’t connect at all?
A: In order for the system to connect (after the receiver is bound) the receiver must receive a
large number of consecutive uninterrupted perfect packets from the transmitter in order to
connect. 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 ft.)
or if the transmitter is located near metal objects (metal TX case, the bed of a truck, the top of
a metal work bench, etc.) connection will take longer and 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 again will cause a connection to occur. This only
happens during the initial connection. Once connected the system is locked in and should a
loss of signal occur (failsafe) the system connects immediately (4ms) when signal is regained.
3. 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 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 thus 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 startup process
of scanning the band and finding the transmitter) and this can take several seconds. Please
read the receiver power requirement section as this explains how to test for and prevent
this occurrence.
4. 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
placed 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.”