Trim....................
Phoinix,
Both brands TM and PW have methods of trimming the TOT and Torque (Q).
The TOT thermocouples on the engine in both cases do not actually output the true value of the MGT/TOT/EGT (delete as required). When the engine is run in the test cell the real TOT is measured and the "trim" value is recorded to make the correction required.
The same applies to the torquemeter shaft. The "datum" and "slope" are compensated. Additionally the torquemeter shaft has a temperature compensation input as well in real time from one of the magnetic pickups which has a temp sensor inside it. (At least on the PW for sure).
The TM uses a "confirmation box" for each value and the PW uses data which is in memory in the Data Collection Unit. All of these units are part of the turbomachine module. They must stay with it. If the modules are changed they must be adjusted in the case of the TM or have the data loaded on the PW.
You will also find the values on the module data plate.
The reason this data is in the STATUS page is to verify that the information is being read correctly and the required values exist. Remember that the VEMD is responsible for determining the display of limits electronically. If BOTH VEMD lanes fail you will have analog data in the CAD. Corrected Q in the PW case and Delta N1 for the TM. These values come direct from the FADEC.