Siemens SINUMERIK 840D sl Function Manual page 475

Example of WAITMC and read-in disabled
M555 is output in channel 3 while the axis is traversing and generates a read-in disabled
(RID). As the WAITMC is appended to BLOCK N312, the wait mark is set and processing in
channel 2 continues.
Channel 2:
N112 G18 G64 X200 Z200 F567
N120 WAITMC(1,2,3)
...
...
...
N170 M30
Channel 3:
N300
N312 G18 G64 D1 X180 Z300 M555
N320 WAITMC(1,2,3)
Wait mark 1 is set in Channels 2 and 3
Channel 2 proceeds with additional processing and program processing in Channel 3 is
stopped because of read-in disabled.
This behavior can be transferred to all available channels.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Mode Groups, Channels, Axis Replacement (K5)
; Processing in Channel 2
; Channel 2 sets wait markers 1, 2 and 3
; Additional processing in Channel 2, as
; WAITMC is added to block N312.
; Additional processing in Channel 2
; End Channel 2
; during travel read-in disabled M555
; Processing in Channel 3
; Wait because of RID
Channels
475