please can anyone tell me whats mean the symbols
like L14,L43 ,L83 ...

I want to know all the symbols

 

The one- or two-digit designation follows a GE-interpretation of the ANSI device numbering scheme.

If you have a Mark V or an early Mark VI Speedtronic turbine control panel, there is a file on the operator interface in the unit-specific directory (usually F:\UNIT1) named LONGNAME.DAT. And, most signals are described in that file, which is sorted, or can be sorted, by the first column. If you have a Mark IV, the "B" sheets in the front of the Speedtronic elementary have signal name descriptions.

The leading "L" (usually) means the signal is a logic signal in the sequencing or application of the turbine control panel. In other words, it's a software signal, not a real, physical device.