MGL Avionics Stratomaster Ultra Horizon XL Owner’s manual
Page 70
Ambient temperature sender
The Stratomaster Flight includes a precision semiconductor temperature probe. It is
recommended that you install it as shown above. The
RED
wire connects to the “Temp probe +”
terminal. The remaining wire is
GREEN
. This wire connects to the “Temp probe –“ terminal.
If you are using the supplied cable connection, wire the RED wire of the probe to the Orange wire
of the connector. The green wire from the probe connects to the green wire of the connector.
The probe head itself should be mounted using suitable means outside of the instrument pod or
aircraft if a closed cockpit aircraft is used. The probe should be placed in the shadow of the pod
or aircraft or in a place were sunlight cannot heat the probe. Also ensure that engine heat or
exhaust gases cannot heat the probe at any time. Remember – the probe is intended to show the
temperature
outside
of your aircraft – not inside.
The twisted cable can be extended should this be required. In this case please use a similar
cable type and continue the twist for the length of the cable.
The probe is required for the display of ambient temperature and density altitude.
We recommend that you install the external temperature probe.
Should you require a suitable replacement probe, it can be obtained from MGL Avionics at
reasonable cost or you can make up your own probe. In this case please obtain a National
Semiconductor Temperature Sensor type LM335 in a TO92 package.
External, visual alarm indicator
If you are using the supplied connector, the alarm output is on the white wire.
The alarm output is a open collector transistor switching to ground (battery minus) in case of an
active alarm.
You can use this to switch a alarm lamp or LED. In case of a LED you need to wire a series
resistor in line with the LED to provide current limiting. Consult your LED data sheet for required
values.
The white wire should be connected to one pole of the lamp or the cathode of the LED. The
remaining pole of the lamp should be connected to +12VDC.
The anode of the LED should be wired to the dropping resistor. The remaining connection of the
dropping resistor should be wired to +12VDC.
Typical values for the dropping resistor are 100 to 500 ohms depending on the amount of current
the LED can handle.
In case of a lamp, do not use a lamp with a greater power rating than 6W at 12 volts.
Maximum current for the alarm line is specified at 0.5A.
