M Functions - Siemens SINUMERIK 840D sl Programming Manual

Fundamentals
2.13 Auxiliary function outputs
Function outputs for travel commands
The transfer of information as well as waiting for the appropriate response takes time and
therefore influences the traversing movements.
High-speed acknowledgment without block change delay
Block change behavior can be influenced by machine data. When the "without block change
delay" setting is selected, the system response with respect to high-speed auxiliary functions
is as follows:
Auxiliary function output
Before the movement
During the movement
After the movement
Function outputs in continuous-path mode
Function outputs before traversing motion interrupt the continuous-path mode (G64 / G641)
and generate an exact stop for the previous block.
Function outputs after the traversing movements interrupt the continuous-path mode
(G64 / G641) and generate an exact stop for the current block.
Important: Waiting for a pending acknowledgment signal from the PLC can also interrupt the
continuous-path mode, e.g. for M command sequences in blocks with extremely short path
lengths.
2.13.1

M functions

The M functions initiate switching operations, such as "Coolant ON/OFF" and other functions
on the machine.
Syntax
M<value>
M[<address extension>] = <value>
344
Response
The block transition between blocks with high-speed auxiliary functions
occurs without interruption and without a reduction in velocity. The auxiliary
function output takes place in the first interpolator clock cycle of the block.
The following block is executed with no acknowledgment delay.
The block transition between blocks with high-speed auxiliary functions
occurs without interruption and without a reduction in velocity. The auxiliary
function output takes place during the block. The following block is execu‐
ted with no acknowledgment delay.
The movement stops at the end of the block. The auxiliary function output
takes place at the end of the block. The following block is executed with no
acknowledgment delay.
CAUTION
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming