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MELSEC-Q
4 THE EXCHANGE BETWEEN THE PLC AND BUFFER MEMORY
4.2.5 Device number designation
The PLC devices are specified using "device codes" and "device numbers."
(1) For A series
The device codes and usable device numbers are as follows.
Device Code
Device
Usable Device Number
1 (&H1)
X (Input)
0
H
to 7FF
H
(0
H
to 1FFF
H
)
2 (&H2)
Y (Output)
0
H
to 7FF
H
(0
H
to 1FFF
H
)
3 (&H3)
M (Internal relay)
0 to 2047 (0 to 8191)
L (Latch relay)
0 to 2047 (0 to 8191)
S (Step relay)
0 to 2047 (0 to 8191)
M (Special relay)
9000 to 9255
4 (&H4)
B (Link relay)
0
H
to 7FF
H
(0
H
to 1FFF
H
)
5 (&H5)
F (Annunciator)
0 to 255 (0 to 2047)
6 (&H6)
T (Timer [contact])
0 to 255 (0 to 2047)
7 (&H7)
T (Timer [coil])
0 to 255 (0 to 2047)
8 (&H8)
C (Counter [contact])
0 to 255 (0 to 1023)
9 (&H9)
C (Counter [coil])
0 to 255 (0 to 1023)
16 (&H10)
T (Timer [current value])
0 to 255 (0 to 2047)
17 (&H11)
C (Counter [current value])
0 to 255 (0 to 1023)
18 (&H12)
D (Data register)
0 to 1023 (0 to 8191)
D (Special register)
9000 to 9255
19 (&H13)
W (Link register)
0
H
to 3FF
H
(0
H
to 1FFF
H
)
20 (&H14)
R (File register)
0 to 8191
The numbers within parentheses for the usable device numbers are device numbers that can be handled by
AnA/AnU/AnUSCPU.
• Use 0 or multiples of 16 for starting device numbers when processing bit
devices in word units.
(9000 or multiples of 16 added to 9000 can be used for special relay M.)
• The extension file register block number is specified in the special tables.
note
(1) The range of device numbers and file register capacity depends on the CPU
specification and parameter set values. For details, refer to the User’s Manual
for the CPU used.
(2) The special relays (M9000 through M9255) and special registers (D9000
through D9255) are separated into read only, write only, and system use.
A PLC CPU error may occur when write is performed to an area outside of the
write only area. For details on special relays and special registers, refer to the
ACPU Programming Manual (Common Commands Edition).
