Mitsubishi Electric MELCEC Q Series User Manual page 78

4. CPU MODULE
(continued)
Function (Application)
Sampling trace
Check the operation status of
the set devices in
chronological order when
QCPU debugs or an abnormal
behavior are caused.
Step operation
Checks condition of program
execution and behavior during
debugging for example.
Clock
Program control by clock data/
external display of clock data
Priority order of LED indication
Changing priority order of
indication/canceling indication
Self-diagnostics function
•An abnormal behavior of the
CPU module
•Preventive maintenance
Boot operation from built-in ROM
Retains programs at power off.
1ms timer
Setting of 1ms timer
Sequence accumulation time
processing
Avoids influence of processing
FROM/TO instruction on
special function modules.
Description
• With respect to a device for which the sampling trace is
set up, the operating condition of the device is sampled
for the number of times specified per scan or per period,
and the results are stored in the extension file register
for the sampling trace of the CPU main module. (The
stored data are cleared by the latch clear operation.)
• Sampling trace is performed by the STRA instruction in
the sequence program.
• Executes operations of the sequence program with one
of the conditions (1) to (5) given below, then stops.
(1) Executes for each instruction.
(2) Executes for each ladder block.
(3) Executes by step intervals and loop counts.
(4) Executes by loop counts and break points.
(5) Executes when the device values matches.
• Executes the clock operation installed to the CPU
module.
• Clock data: year, month, day , hour, minute, second, day
of the week
• When the clock data read request (M9028) is on, the
clock data are read and stored in D9025 to D9028 by the
clock element after the END processing of the sequence
operation.
• The clock elements are bucked up by a battery of the
CPU main module.
• For ERR. LED indication except for operation stop,
changing order of indication/canceling indication are
executed.
• When an error that matches one of the self-diagnostics
items is generated at the CPU module power on or
during RUN, QCPU prevents malfunctions by stopping
the CPU module operation and indicating the error.
• Stores the error codes corresponding to the self-
diagnostics item.
• Boot operation can be performed by booting parameters
and sequence programs from the built-in ROM to the
built-in RAM at start-up.
• In addition to the conventional high-speed timer (10ms)
and low-speed timer (100ms), a 1ms timer can be used.
• When the faster scan time affects the processing of
FROM/TO instruction or the scan time for special
function modules, a special relay (M9077) and special
register (D9077) are used to avoid such problems.
4 - 32
Overview of Setting and Operation
• Using the peripheral devices, set
the device to which the status latch
is performed and the extension file
register where the data are stored.
• Using the peripheral devices,
monitor the result of the sampling
trace.
• Selects a step operation condition
for the peripheral device and
executes.
• Sets data for D9025 to D9028 by a
peripheral device, turns on M9025,
then write to the clock element.
• Writes to the clock element by the
sequence program. (Dedicated
instructions can be used.)
• Writes data as to whether change
order/cancel indication to D9038 or
D9039 by the sequence program.
• There are some self-diagnostics
items with which the operation can
be continued or stopped by the
setting of peripheral device
parameters.
• Reads the error codes with the
peripheral devices and performs
troubleshooting.
(Refer to Section 4.1.4.)
• Sets DIP switch 3 to on and power
on or reset the module. (BOOT LED
turns on.) (Refer to Section 4.4.1.)
• Adds ZHTIME, a 1ms timer setting
instruction, during programming.
(Refer to Section 4.4.2.)
• Uses M9077 and D9077 as interlock
to execute FROM/TO instruction in
the unit of several ms. (Refer to
Section 4.4.3.)