Mitsubishi Electronics FX3G User Manual

FX

3S

/FX

3G

/FX

3GC

/FX

3U

/FX

3UC

 Series

Programming Manual - Basic & Applied Instruction Edition

37 Operation of Special Devices (M8000 -, D8000 -)

The device numbers and functions of the special auxiliary relays (indicated as "special M" in tables) and special data
registers (indicated as "special D" in tables) are shown below.
Note that functions of certain devices vary depending on the series of the PLC.
Do not use the undefined / blank special auxiliary relays and special data registers in the sequence program since
they are occupied by the CPU.
In addition, do not activate or write to the devices with brackets on the first letter such as [M]8000 or [D]8001 in the
program.

→ Refer to Section 37.2 for supplementary information on analog special adapter devices.

[M]8000
RUN monitor
NO contact

→Refer to Subsection 37.2.1.

–

[M]8001
RUN monitor
NC contact

–

[M]8002
Initial pulse
NO contact

–

[M]8003
Initial pulse
NC contact

–

[M]8004
Error occurrence

•

FX

3S

/FX

3G

/FX

3GC

/FX

3U

/FX

3UC

ON when either M8060, M8061, M8064,
M8065, M8066, or M8067 is ON.

•

FX

1S

/FX

1N

/FX

1NC

/FX

2N

/FX

2NC

ON when either M8060, M8061, M8063,
M8064, M8065, M8066, or M8067 is ON.

D8004

[M]8005
Battery voltage low

ON when battery voltage is below the value set
in D8006.

→Refer to Subsection 37.2.3.

–

D8005

–

–

–

[M]8006
Battery error latch

It is set when battery voltage low is detected.

→Refer to Subsection 37.2.3.

–

D8006

–

–

–

[M]8007
Momentary power 
failure

ON for 1 scan, when momentary power failure
is detected
Even if M8007 turns ON, PLC continues to
RUN as long as the duration of power loss is
within the time period specified in D8008.

→Refer to Subsection 37.2.4.

–

–

–

D8007
D8008

–

–

–

[M]8008
Power failure 
detected

It is set when momentary power failure is
detected.
If power loss time is longer than the time period
specified in D8008, M8008 is reset and PLC is
switched to STOP mode. (M8000=OFF).

→Refer to Subsection 37.2.4.

–

–

–

D8008

–

–

–

[M]8009
24V DC down

ON when 24 V DC power fails in an I/O
extension unit or special function block.

–

D8009

–

–

–

1 scan time

RUN

input

M8000

M8001

M8002

M8003

M8061

Error occurrence