Operation And Test [Power On And Plc Running]; Self-Diagnostic Function; Test Functions - Mitsubishi FX3UC SERIES User Manual

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
12.3

Operation and Test [Power ON and PLC Running]

12.3.1 Self-diagnostic function

When the PLC's power is turned on, its self-diagnostic function starts automatically. If there are no problems
with the hardware, parameters or program, the PLC will start and the RUN command (refer to Section 12.2) is
given (RUN LED is lit).
If any problems are found, the "ERR" LED flashes or lights.

12.3.2 Test functions

Functions of the programming tool to turn on/off the PLC devices and change the current values/settings are
effective or ineffective depending on the PLC status as shown below.
*1
Forcible ON/OFF
Change of current values of timers, counters,
data registers, extension registers, extension
file registers and file registers
Change of settings of timers and counters
*1. Forcible ON/OFF
- The forcible ON/OFF function is effective on the input relays (X), output relays (Y), auxiliary relays
(M), state (S), timers (T) and counters (C). On the display module, the function cannot be operated
for the input relays (X).
- The forcible ON/OFF function can turn on or off the devices only for one scan.
While the PLC is running, the function is substantially effective in clearing the current values of the
timers (T), counters (C), data registers (D), index registers (Z and V) and extension registers (R)
and in controlling the SET/RST circuit and self-retaining circuit. (The operation to forcibly turn on
timers is effective only when the timers are driven by the program.)
- The results of forcible ON/OFF operation performed while the PLC in the stopped state or
performed for devices not used in the program are retained.
However, the results of the operation performed for the input relays (X) are not retained because
the relays refresh input even while the PLC is in the stopped state. (They are updated according to
the input terminal conditions.)
*2. Since the current values may be changed according to MOV instruction in the program and the
operation results, the most recently obtained values are retained.
*3. Only display modules can change the current value by the extension file register test function.
*4. The current values of the file registers stored in the program memory cannot be monitored or tested
on the display module.
*5. Change of timer and counter settings
The settings of the timers (T) and counters (C) can be changed only when the timers are driven by the
program.
12 Test Operation, Adjustment, Maintenance and Troubleshooting
Item
Devices used in program
Devices not in use
Devices used in program
Devices not in use
*4
When the program memory is the built-in
RAM
When the program memory is in the memory
*5
cassette and the PROTECT switch is on
When the program memory is in the memory
cassette and the PROTECT switch is off
12.3 Operation and Test [Power ON and PLC Running]
: Conditionally effective −: Ineffective
: Effective
12
In running In stopped
status status
*1 *1
*2*3 *3
*3 *3
− −
−
387
11
A
B
C
D
E
F