Siemens sinumerik 808d Programming And Operating Manual page 191

NSP (starting point offset) and NUMTH (number)
You can use this parameter to program the angle value defining the point of the first cut of
the thread turn at the circumference of the turned part. This involves a starting point offset.
The parameter can assume values between 0 and +359.9999 degrees. If no starting point
offset has been specified or the parameter has been omitted from the parameter list, the first
thread turn automatically starts at the zero-degree mark.
Use the NUMTH parameter to define the number of thread turns with a multiple-turn thread.
For a single-turn thread, the parameter must be assigned zero or can be dropped completely
in the parameter list.
The thread turns are distributed equally over the circumference of the turned part; the first
thread turn is determined by the NSP parameter.
To produce a multiple-turn thread with an asymmetrical arrangement of the thread turns on
the circumference, the cycle for each thread turn must be called when programming the
appropriate starting point offset.
PIT (thread pitch) and PITA (unit of thread pitch)
The thread lead is an axis-parallel value and is specified without sign. The unit of it is defined
in parameter PITA.
PITA = 1 pitch in mm/revolution
= 2 pitch in threads per inch (TPI)
VARI (machining type)
By using the VARI parameter, it is defined whether external or internal machining will be
carried out and which technology will be used with regard to the infeed when roughing. The
VARI parameter can assume values between 1 and 4 with the following meaning:
Turning Part 2: Programming (Siemens instructions)
Programming and Operating Manual, 05/2012, 6FC5398-5DP10-0BA0
Cycles
2.5 Turning cycles
191