Siemens SIMATIC FM 453 Manual page 311

10.2 Program Execution and Direction of Machining
Forward
As a rule, programs are processed by ascending block number.
Processing
Reverse
If programs are processed in reverse, the effects of commands must be taken
Processing into account in the programming:
For these reasons, a distinction can be made between forward processing and
reverse processing, in terms of both geometry and block transition response.
10.3 Block Transitions
Overview
This chapter describes the influence of certain commands on block transi-
tions.
Exact Positioning - G60 mode is overlaid with G50 and G88 to G89 (force block change on-the-
G60 fly).
The program advances to the next block when the target range is reached.
The influence of M functions is as indicated in machine data item MD32.
Output of
Case 1
M Function Before
V
Positioning
M
FM 453 Servo Drive / Step Drive Positioning Module
C79000-G7076-C453-01
Commands are self-maintaining (G90, G91, G60, G64, G30...G39)
Active tool offset (G43, G44, D0...D20)
Change of coordinate systems via G87, G88, G89.
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Writing Traversing Programs
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