Mitsubishi MELSEC-Q Series Programming Manual page 715

Function
The sampling trace function collects the specified device data of a CPU module consecutively at
the specified timing.
With the sampling trace function, the traced results obtained through the specified number of
trace operations will be stored to the sampling trace file of the memory card when SM800,
SM801, and SM802 are turned ON.
SM800
(Preparation for sampling trace)
SM801
(Starting sampling trace)
SM802
(During the execution of sampling
trace)
SM803
(Trigger for sampling trace)
SM804
(After the execution of sampling
trace trigger)
SM805
(Completion of sampling trace)
TRACE
Trace start request Trigger condition enabled
Total number of traces
TRACE, TRACER
Trace ends by
number of trace
after trigger
Number of trace
after trigger
8.2 Trace Set/Reset
8
TRACER
Trace reset
8-7