TLA is thrust lever angle, the angle of the thrust lever in the cockpit.
TRA is thrust resolver angle, the angle of the resolver giving the position of the TLA to the EEC. The EEC uses the thrust lever resolvers (TLRs) on the aisle
stand to get thrust resolver angle (TRA). The EEC uses this data
to find the commanded engine thrust. The EEC also sends TRA
to the autothrottle computer.
You can see the mnemonics in the cdu, use the mnemonics for
aileron left its AILLINP.X
aileron right AILRINP.X
rudder RUDDINP.X
elevator ELEVLINP.X and ELEVRINP.X
You can access these via the acms menu, if im correct in the RH CDU only, depends on your config. else via the MIDU.
see this list:
http://www.sjap.nl/mnemonic%20list%20737%20NG.pdf
Hoep these answers are of any help?
If anybody has more / other / different info, please reply!
best regards
sjap