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MELSEC-Q
11 TROUBLESHOOTING
Special Relay List
(4) Scan information
Number
Name
Meaning
Explanation
Set by
(When Set)
Corresponding
ACPU
M9
Applicable
CPU
SM510
Low speed
program
execution flag
OFF : Completed or not
executed
ON : Execution under way.
• Goes ON when low speed execution type program is
executed.
S
(Every END
processing)
New
SM551
Reads module
service interval
OFF : Ignored
ON : Read
• When this relay goes from OFF to ON, the module
service interval designated by SD550 is read to SD551 to
SD552.
U New
+Rem
(5) Memory cards
Number
Name
Meaning
Explanation
Set by
(When Set)
Corresponding
ACPU
M9
Applicable
CPU
SM600
Memory card
usable flags
OFF : Unusable
ON : Use enabled
• ON when memory card is ready for use by user S (Initial) New
SM601
Memory card
protect flag
OFF : No protect
ON : Protect
• Goes ON when memory card protect switch is ON S (Initial) New
SM602 Drive 1 flag
OFF : No drive 1
ON : Drive 1 present
• Goes ON when loaded memory card is RAM. S (Initial) New
SM603 Drive 2 flag
OFF : No drive 2
ON : Drive 2 present
• Goes ON when loaded memory card is ROM. S (Initial) New
SM604
Memory card
in-use flag
OFF : Not used
ON : In use
• Goes ON when memory card is in use S (Initial) New
SM605
Memory card
remove/insert
prohibit flag
OFF : Remove/insert enabled
ON : Remove/insert
prohibited
• Goes ON when memory card cannot be inserted or
removed
U New
SM609
Memory card
remove/insert
enable flag
OFF : Remove/insert
prohibited
ON : Remove/insert enabled
• Turned ON by user to enable the removal/insertion of
memory card.
• Turned OFF by the system after the memory card is
removed.
U/S New
• Always ON S (Initial) New QCPU
SM620
Memory card B
usable flags
OFF : Unusable
ON : Use enabled
• ON when memory card B is ready for use by user S (Initial) New
Q2A (S1)
Q3A
Q4A
Q4AR
• Always ON S (Initial) New QCPU
SM621
Memory card B
protect flag
OFF : No protect
ON : Protect
• Goes ON when memory card B protect switch is ON S (Initial) New
Q2A (S1)
Q3A
Q4A
Q4AR
• Always ON S (Initial) New QCPU
SM622 Drive 3 flag
OFF : No drive 3
ON : Drive 3 present
• Goes ON when drive 3 (card 2 RAM area) is present S (Initial) New
Q2A (S1)
Q3A
Q4A
Q4AR
• Always ON S (Initial) New QCPU
SM623 Drive 4 flag
OFF : No drive 4
ON : Drive 4 present
• Goes ON when drive 4 (card 2 ROM area) is present S (Initial) New
SM624
Memory card B
in-use flag
OFF : Not used
ON : In use
• Goes ON when memory card B is in use S (Initial) New
SM625
Memory card B
remove/insert
prohibit flag
OFF : Remove/insert enabled
ON : Remove/insert
prohibited
• Goes ON when memory card B cannot be inserted or
removed
U New
Q2A (S1)
Q3A
Q4A
Q4AR
SM640 File register use
OFF : File register not used
ON : File register in use
• Goes ON when file register is in use
S (Status
change)
New
SM650 Comment use
OFF : File register not used
ON : File register in use
• Goes ON when comment file is in use
S (Status
change)
New
SM660 Boot operation
OFF : Internal memory
execution
ON : Boot operation in
progress
• Goes ON while boot operation is in process
• Goes OFF if boot designation switch is OFF
S (Status
change)
New
SM672
Memory card A
file register
access range flag
OFF : Within access range
ON : Outside access range
• Goes ON when access is made to area outside the range
of file register R of memory card A
(Set within END processing.)
• Reset at user program
S/U New