Spektrum SPMAR7100 - Manual (Page 12)

Spektrum AR7100 21 Spektrum AR7100 22
QuickConnect with Brownout Detection Tips on Using 2.4GHz Systems
The remote receiver included with the AR7100 and AR7100R feature
QuickConnect with Brownout Detection. Should a power interruption
occur (brownout), the system will reconnect immediately when
power is restored and the LEDs on each connected receiver will flash
indicating a brownout (power interruption) has occurred. Brownouts
can be caused by an inadequate power supply (weak battery or
regulator), a loose connector, a bad switch, an inadequate BEC when
using an electronic speed controller, etc. Brownouts occur when the
receiver voltage drops below 3.2 volts thus interrupting control as the
servos and receiver require a minimum of 3.2 volts
to operate.
How Brownout Detection Works
When the receiver voltage drops below 3.2 volts the system drops
out (ceases to operate). When power is restored, the receiver will
immediately attempt to reconnect to the last two frequencies that it
was connected to. If the two frequencies are present (the transmitter
was left on), the system reconnects typically in about 4ms. The
receiver will then blink indicating a brownout has occurred. If at
any time the receiver is turned off then back on and the transmitter
is not turned off, the receiver will blink as a power interruption was
induced by turning off the power to the receiver. In fact this simple
test (turning off then on the receiver) will allow you to determine
if your system’s brownout detection is functioning. Note: If a
brownout occurs in flight it is vital that the cause of the brownout be
determined and corrected. QuickConnect and Brownout Detection are
designed to allow you to safely fly through most short duration power
interruptions. However, the root cause of these interruptions must be
corrected before the next flight to prevent catastrophic safety issue.
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 off 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 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 then turned on for a short
period (the time it takes to connect) all servos except for the
throttle are driven to their preset failsafe positions while the
throttle has no output pulse. The receiver 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 that 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.