MGL Avionics Stratomaster Ultra “L” Owner’s manual
Page 70
RDAC EIS unit thermocouple inputs
Thermocouple inputs – details
The RDAC EIS provides four thermocouple inputs for use with EGT and CHT probes. Both K as
well as J type probes can be used. K types are used for EGT probes while most CHT probes are
also K types. Some makes of CHT probes are J type. The probe type selection is done in the
Device Setup Menu (Sender Type Selection). Incorrect selection will lead to incorrect temperature
display.
The RDAC IV EIS will accept both grounded and isolated thermocouple probes. Your only
consideration in case of the more common grounded configurations is that you need to ensure
that the thermocouple mounting position (Exhaust flange, etc) is at the same electrical potential
as the negative supply line of the Stratomaster Ultra (normally the – (minus) of the battery). The
RDAC unit has an earth point marked “ground” that you should connect to the engine block via a
short cable.
Probe usage depends on your setup of the Stratomaster Ultra, mainly the “Bargraph type
selection” and other items in the “Engine Detail Setup”.
Typical choices are:
2xEGT
Rotax 582, 912, 914
2xEGT 2xCHT Rotax 503, 582, VW
1xEGT 2xCHT Rotax 447
4xEGT
Rotax 912, 914 (in addition to two NTC CHT channels)
The above are only the more common selections.
The thermocouple amplifier is a precision device providing full cold junction compensation and
bow voltage correction. In addition the amplifier measures and corrects for its own errors. This
Typical Thermocouple setup, here shown for two EGT
and two CHT probes. Note that the probes are colour
coded. Yellow wires must connect to the Y terminals and
the red wires must connect to the R terminals.
