Siemens SINUMERIK 840Di Function Manual page 499

2.8 Auxiliary functions without block change delay
2.8
Function
For auxiliary functions with parameterized and/or programmed output behavior, too:
• "Output duration one OB40 cycle (quick acknowledgment)"
• "Output prior to motion" or "Output during motion"
continuous-path mode can cause drops in velocity in continous-path mode (short traverse
paths and high velocities). This is because it is necessary to wait for acknowledgment of the
auxiliary function by the PLC toward the end of the block.
To avoid these velocity drops, the block change can be made irrespective of whether such
auxiliary functions have been acknowledged:
MD22100 $MC_AUXFU_QUICK_BLOCKCHANGE (block change delay with fast auxiliary
functions)
Constraints
Synchronism of auxiliary functions that are output without a block change delay is no longer
ensured for the part program block in which they are programmed. In the worst case,
acknowledgment comes one OB40 cycle and execution of the auxiliary function comes one
OB1 cycle after the change to the next part program block.
2.9 Associated auxiliary functions
2.9
Function
Associated auxiliary functions are user-defined auxiliary functions that have the same effect
as the corresponding predefined auxiliary functions. For the following predefined auxiliary
functions, user-defined auxiliary functions can be associated:
• M0 (stop)
• M1 (conditional stop).
Requirements
The precondition for association of a user-defined auxiliary function with one of the
predefined auxiliary functions mentioned is parameterization of a user-defined auxiliary
function. Only M is permitted as parameter "Type" of the user-defined auxiliary function.
Parameterization
Association of a user-defined auxiliary function with one of the predefined auxiliary functions
mentioned is set in the following machine data:
Auxiliary Function Output to PLC (H2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2.8 Auxiliary functions without block change delay
Detailed Description
2-25