Siemens SIMATIC S7-300 Manual page 278

Writing Traversing Programs
Change block on- There are a number of conditions that may delay or prevent a block change
the-fly - G64
on-the-fly. Here a distinction is necessary between the case in which this type
(deceleration)
of block change is suppressed intentionally, and the case in which the se-
lected function does not permit a block change on-the-fly.
V
M
1 – Since the M output is completed at the point of deceleration, a block
2 – The M output is not yet complete at the point of deceleration. The axis
3 – Axis comes to a complete standstill and waits for the end of M output.
10-18
Block change on-the-fly is suppressed:
– By removing the Enable read-in control signal - this stops program
processing at the end of the current block. To continue the program,
the enable must be re-input.
– By output of the M function before or after positioning.
– By M function M0 (stop at end of block). To continue the program,
the START control signal must be reset.
– By a block with a dwell time.
– By processing a program in the Automatic/Single Block mode. Each
block must be activated individually.
– By a change in the acceleration override.
Functions that themselves prevent block change on-the-fly:
– M functions (during positioning).
1
V
t
M
É É É É É É É
t
É É É É É É É
change takes place on-the-fly.
begins to brake. At the end of the M output, the axis returns to speed
(transition on-the-fly from deceleration ramp to acceleration ramp).
2
V
3
t
M
É É É É
t
É É É É
FM 354 Servo Drive Positioning Module
t
t