Special Registers; Plc Status Diagnostic Information (D8000 To D8009 - Mitsubishi Electric FX Series Training Manual

Special Registers

Special Registers
A.2
Just like the special relays (section A.1) starting at address M8000 the FX controllers also have
special or diagnostic registers, whose addresses start at D8000. Often there is also a direct con-
nection between the special relays and special registers. For example, special relay M8005
shows that the voltage of the PLC's battery is too low, and the corresponding voltage value is
stored in special register D8005. The following tables shows a small selection of the available
special registers as examples.
Special registers can be divided in two groups:
– Special registers whose value can only be read by the program
– Special relays whose value can be read and written by the program.
The following tables feature a "Read" and a "Write" column. If the symbol "b" is shown in a one of
these columns, the corresponding action is possible. The symbol "—" means that the corre-
sponding action is not allowed.
A.2.1

PLC Status Diagnostic Information (D8000 to D8009)

Special Register
D8000
D8001
D8002
D8003
D8004
D8005
D8006
D8007
D8008
D8009
A - 6
Read Write CPU
© ©
©
—
FX
1S
FX
1N
FX
2N
©
FX
— 2NC
FX
3G
FX
3U
FX
3UC
©
—
©
—
— —
FX
2N
FX
2NC
FX
3G
— —
FX
3U
FX
3UC
FX
2N
FX
2NC
— —
FX
3U
FX
3UC
FX
2N
FX
2NC
— —
FX
3U
FX
3UC
FX
2N
FX
2NC
— —
FX FX
3G 3U
FX
3UC
Function
Watchdog timer setting (in 1ms steps). (Writes from system
ROM at power ON) Value overwritten by program is valid
after END or WDT instruction execution. The setting must be
larger than the maximum scan time (stored in D8012).
Default value is 200 ms.
PLC type and system version
FX : 22V
1S
VV
FX /FX : 26V
1N 3G
VV
FX /FX /FX /FX : 24V
2N 2NC 3U 3UC
Version 1.00 ® 26100)
(e. g. FX
1N
Memory capacity
0002 ® 2k steps (FX
only)
1S
0004 ® 4k steps (FX
/FX
2N 2NC
0008 ® 8k steps or more (not for FX
If 16K steps or more "K8" is written to D8002 and "16", "32"
or "64" is written to D8102.
Memory typ:
® RAM (Memory cassette)
00
H
® EPROM (Memory cassette)
01
H
® EEPROM (Memory cassette or flash memory)
02
H
® EEPROM (Memory cassette or flash memory,
0A
H
write-protected)
® Built-in memory in PLC
10
H
Error number (M)
If D8004 contains e.g. the value 8060, special relay M8060 is
set.
Battery voltage (Example: "36" -> 3.6 V)
Low battery voltage detection level.
Default settings:
FX /FX : 3.0 V ("30")
2N 2NC
FX /FX /FX : 2.7 V ("27")
3G 3U 3UC
Momentary power failure count
Operation frequency of M8007 is stored. Cleared at
power-off.
Power failure detection
Default settings:
FX /FX : 10 ms (AC power supply)
2N 3U
FX /FX : 5 ms (DC power supply)
2NC 3UC
24V DC failed device
Minimum input device number of extension units and exten-
sion power units in which 24V DC has failed.
Appendix
VV
only)
)
1S
MITSUBISHI ELECTRIC