Siemens sinumerik 840D sl Operating Manual page 295

Parameters
Parameters, G code program (thread, conical)
PL Machining plane
SC Safety clearance
F Feedrate
Parameters
P
G
Machining
Turning
Operating Manual, 07/2010, 6FC5398-8CP40-0BA0
Description
DA Thread changeover depth (inc)
First machine all thread turns sequentially to thread changeover
depth DA, then machine all thread turns sequentially to depth 2 ·
DA, etc. until the final depth is reached.
DA = 0: Thread changeover depth is not taken into account, i.e.
finish machining each thread before starting the next thread.
Complete, or
Machining: 
from turn N1

N1 (1...4) start thread N1 = 1...N
only thread NX

NX (1...4) 1 from N threads
mm
mm/min
Description
Thread pitch in mm/revolution

Thread pitch in inch/revolution

Thread per inch

Thread pitch in MODULUS

Change in thread pitch per revolution - (only for P = mm/rev or in/rev)
G = 0: The thread pitch P does not change.
G > 0: The thread pitch P increases by the value G per revolution.
G < 0: The thread pitch P decreases by the value G per revolution.
If the start and end pitch of the thread are known, the pitch change to be
programmed can be calculated as follows:
|P - P |
2 2
e
G = ----------------- [mm/rev2]
2 * Z
1
The meanings are as follows:
P : End pitch of thread [mm/rev]
e
P: Start pitch of thread [mm/rev]
Z : Thread length [mm]
1
A larger pitch results in a larger distance between the thread turns on the
workpiece.
∇ (roughing)

∇∇∇ (finishing)

∇ + ∇∇∇ (roughing and finishing)

Programming technology functions (cycles)
or
Parameters, ShopTurn program (thread, conical)
T Tool name
D Cutting edge number
F Feedrate
S / V Spindle speed or constant
cutting rate
8.2 Rotate
Unit
mm/min
mm/rev
rpm
m/min
Unit
mm/rev
in/rev
turns/"
MODULUS
295