MXS System Description and Installation Manual
UM06945
© Sagetech Avionics 2022 Proprietary Confidential
Page 50 of 56
BIT1
7
(msb)
RF Loopback Test
Pass
The MXS initiates a loop-back test of the
1030 and 1090 MHz RF circuitry and FPGA.
The 1030 and 1090 MHz loop-back test is
part of the BIT and is ran once at startup
and then must be enabled using the
Military Settings message. It sends an RF
Test signal that switches into the front end
of the receivers. The loop-back test passes
if and only if a healthy signal is measured
by the receiver for all configured antennas.
If either loop-back test fails, the MXS sets
the ‘Loop
-
Back Fail Flag’. The
MXS clears
the ‘Loop
-
Back Fail Flag’ if both loop
-back
tests are passing.
Test is part of the Continuous BIT suite of tests.
XPDR Fail Flag is set in the ACK message to the Host.
If flagged, first remedy is to
power cycle the unit. If error
is still triggered, then there
could be an RF interference
issue on the Platform or in
the surrounding area. If the
error persists and there is no
RF interference, then unit is
damaged.
6
53V Power Valid
If the Operational Mode is ALT or ON
(hence the 53V supply is enabled to power
the transmitter) and the voltage is less
than 51 V or greater than 55 V, then the
MXS sets the 53V Voltage Failure
Indication; else clears it. The 53V Power
Valid flag is the invert 53V Voltage Failure
indication.
Test is part of the Continuous BIT suite of tests.
XPDR Fail Flag is set in the ACK message to the Host.
If this fails, re-send the host
“On” or “Alt” operating
message. Check to make
sure the power supply is not
limiting. The unit is damaged
if these conditions are
checked, and a failure still
persists.
5
ADC Ready
This signal is set when 256 consecutive
correct framing samples are received from
the ADC
Test is part of the Continuous BIT suite of tests.
XPDR Fail Flag is set in the ACK message to the Host.
Attempt a Power cycle. The
unit is damaged if the failure
persists
4
Pressure
Transducer Ready
If the MXS is unable to read the pressure
sensor, then the MXS
set ‘Pressure Sensor
Failed’ to True, else False. The Pressure
Transducer Ready flag is the inverted
Pressure Sensor Failed bit
Test is part of the Continuous BIT suite of tests.
XPDR Fail Flag is set in the ACK message to the Host.
Attempt a Power cycle. The
unit is damaged if the failure
persists. Alternatively,
pressure altitude data may
be received from the Host
interface. Systems using the
Host provide pressure
altitude data can ignore this
fault
3
FPGA Ready
Processor writes to FPGA firmware register
and then reads back an expected value
Test is part of the Continuous BIT suite of tests.
XPDR Fail Flag is set in the ACK message to the Host.
Attempt a Power cycle. The
unit is damaged if the failure
persists
