800
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
36 Operation of Special Devices (M8000 -, D8000 -)
36.1 Special Device List (M8000 -, D8000 -)
36. Operation of Special Devices (M8000 -, D8000 -)
36.1
Special Device List (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 36.2 for supplementary information on analog special adapter devices.
36.1.1
Special Auxiliary Relay (M8000 to M8511)
Number and name
Operation and function
Applicable model
FX
3U
FX
3UC
Correspond-
ing special
device
FX
1S
FX
1N
FX
2N
FX
1NC
FX
2NC
PLC Status
[M]8000
RUN monitor
NO contact
→
Refer to Subsection 36.2.1.
3
3
–
3
3
3
3
3
[M]8001
RUN monitor
NC contact
3
3
–
3
3
3
3
3
[M]8002
Initial pulse
NO contact
3
3
–
3
3
3
3
3
[M]8003
Initial pulse
NC contact
3
3
–
3
3
3
3
3
[M]8004
Error occurrence
•
FX
3U
, FX
3UC
ON when either M8060, M8061, M8064, M8065,
M8066, or M8067 is ON.
•
FX
1S
,FX
1N
,FX
2N
,FX
1NC
,FX
2NC
ON when either M8060, M8061, M8063, M8064,
M8065, M8066, or M8067 is ON.
3
3
D8004
3
3
3
3
3
[M]8005
Battery voltage low
ON when battery voltage is below the value set in
D8006.
→
Refer to Subsection 36.2.3.
3
3
D8005
–
–
3
–
3
[M]8006
Battery error latch
It is set when battery voltage low is detected.
→
Refer to Subsection 36.2.3.
3
3
D8006
–
–
3
–
3
[M]8007
Momentary power
failure
ON for 1 scan, when detecting momentary power
failure
Even if M8007 turns ON, PLC continues to RUN
mode in case duration of power loss is within period
of time specified in D8008.
→
Refer to Subsection 36.2.4.
3
3
D8007
D8008
–
–
3
–
3
[M]8008
Power failure
detected
It is set when momentary power failure is detected.
If power loss time is longer than period of time
specified in D8008, M8008 is reset and PLC is turned
in STOP mode.(M8000=OFF).
→
Refer to Subsection 36.2.4.
3
3
D8008
–
–
3
–
3
[M]8009
24V DC down
ON when 24V DC power fails in either powered
extension unit or extension power supply unit
*1
.
3
3
D8009
–
–
3
–
3
*1.
Powered extension units are applicable only to FX
1N
/FX
2N
/FX
3U
PLCs.
Extension power supply units are applicable only to FX
3UC
PLCs.
1 scan time
RUN
input
M8000
M8001
M8002
M8003
M8061
Error occurrence