Programming The Smoothing Exponent With G92 T - Siemens SINUMERIK 880 Programming Manual

4 Programming of Motion Blocks

4.4.4 Programming the smoothing exponent with G92 T..

4.4.4 Programming the smoothing exponent with G92 T . .
This function is used to protect the drive when cutting threads and to obtain a better speed
stability.
The feed run-up time until synchronization with the running workspindle, can be programmed
using the command G92 T. . . The feed run-up time should be matched to the run-in path
available:
• Short run-in path, short run-up time, low T value
• Long run-in path, Long run-up time, high T value
The programmed run-up time also acts as smoothing time, i.e. the actual spindle speed is
averaged via this value. An even feedrate is thus obtained.
The smoothing and feed run-up time depends on
• the programmed value T..
• the interpolation clock path set in NC MD 155. This machine data should only be
changed by a properly trained specialist.
Standard setting on SINUMERIK 880 GA1, SW6 is 20 ms
Standard setting on SINUMERIK 880 GA2, SW1 is 8 ms
The value T . . must be an integer. Possible values are 0...5. The following table shows which
T value has to be programmed for a set interpolation clock path in order to obtain the required
feed run-up time.
Programmed value T..
Multiplier
Feed run-up time to thread feedrate (ms)
for an interpolation clock path of 20 ms
Feed run-up time to thread feedrate (ms)
for an interpolation clock path of 8 ms
Calculation of the run-up time for any given interpolation clock path
A multiplier, which can be taken from the table, corresponds to each T value. For example,
value T1 has 2 as multiplier, value T2 has 4 as multiplier etc.
The run-up time is calculated as follows:
Run-up time (ms) = multiplier · interpolation cycle (ms)
Example for the calculation of the run-up time:
An interpolation clock path of 8 ms is specified in NC MD 155. G92 T2 has been programmed
in the NC program.
The table shows that the multiplier has the value 4 (for T2).
The run-up time is the product 4.8 ms = 32 ms.
4–66
0 1
1 2
20 40
8 16
© Siemens AG 1991 All Rights Reserved
01.93
2 3 4 5
4 8 16 32
80 160 320 640
32 64 128 256
6ZB5 410-0HD02
SINUMERIK 880, (PG)