Hello, I'm using telemetry on my nitro model and recently added the MT300EX sensor with it's dual temperature sensors. I'm using the Spektrum SPM4651T with DX9 transmitter and Brain 2 BT. Currently the two separate temperatures are visible on the live data of the Brain, but there is only one temp shown on the telemetry of the transmitter. After some testing I found out that the temperature sent to the TX is the highest of the two and if I disconnect one of the two temperature sensors the received temperature goes mad. I double checked everything with the Brain manual, reset and auto-configured the telemetry, but the issue persists. If the two temps can't be sent, we should at least be able to select which one of the two to view from the TX.
For motors and all other devices it is high temperatures that indicate a critical and dangerous situation.
Low temperatures are never dangerous (unless they are below -20°C, which are not yet measured by the current sensors available on the market).
Unfortunately, unlike other radio systems (OpenTX, Jeti, Graupner, etc.) which provide for the telemetry, the transmission of two different and separate temperature values, the telemetry pages of Spektrum transmitters provide for the telemetry transmission of two separate temperatures only for ESCs.
For other telemetry parameters only one temperature value is displayed.
For this reason we have chosen for Spektrum systems to transmit the higher of the two temperatures.
In case, instead of measuring the cylinder temperature, you want to measure the crankcase to check if the high temperature indicates too lean carburation or if the low temperature indicates too fat carburation, simply disconnect the second temperature sensor.
Since with all other radio systems it is not necessary to deactivate by means of a new parameter to be added to the already many configuration parameters of the software, and since it is much faster and easier to disconnect a connector than to connect with an app to the FCU and then change a configuration parameter, we have not provided the function you ask for and we do not even plan to include it in the future.
Especially since, as you have seen, the two different temperature values are logged by the control unit not only in the flight logs but also in real time and once you are connected to the control unit through an app, you can view the two temperatures in real time.
Regarding your report of problems when one of the two sensors is disconnected, we thank you very much for your report!
We will definitely do some checking and if we can also reproduce the problem with the sensors we have available, we will definitely fix it before the next release.
In addition, we will also check with Spektrum's developers to see if they can modify one of the various telemetry parameters managed with their Airware software on their transmitters to be able to display two different temperatures on one of their various telemetry pages.
@customercare Thank you for the explanation, I hope spektrum can implement this feature. I will also be glad to help logging the issue with disconnecting the second temp sensor. This info will also be a great addition to the manual for nitro telemetry!