Auxiliary Relay [M]; Numbers Of Auxiliary Relays - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
2.3

Auxiliary relay [M]

There are many auxiliary relays inside the PLC. Coils of auxiliary relays are driven by contacts of various
devices inside the PLC in the same way as output relays.
Auxiliary relays have many electronically normally-open contacts and normally-closed contacts which can be
used arbitrarily inside the PLC.
However, external loads cannot be driven directly by these contacts. External loads should be driven by
output relays.
2.3.1

Numbers of auxiliary relays

The table below shows auxiliary relay (M) numbers. (Numbers are assigned in decimal.)
1. FX /FX /FX
3S 3G 3GC
FX FX
3U/ 3UC
PLC
FX /FX
3G 3GC
PLC
FX PLC
3S
*1. This area is not latched (backed up). It can be changed to the latched (backed-up) area by parameter
setting.
*2. This area is latched (backed up). It can be changed to the non-latched (non-backed-up) area by
parameter setting.
*3. The characteristics of latch (backup) cannot be changed using parameters.
*4. They can be changed to the latched (battery backed-up) type using parameters while an optional
battery is attached. However, the latched area cannot be set.
When simple N:N link or parallel link is used, some auxiliary relays are occupied for the link.
2. FX /FX /FX
1S 1N 1NC
General
M0 to M383
FX PLC
1S
384 points
M0 to M383
FX /FX
1N 1NC
PLC
384 points
M0 to M499
FX /FX
2N 2NC
PLC
500 points
*1. This area is not latched (backed up). It can be changed to the latched (backed-up) area by parameter
setting.
*2. This area is latched (backed up). It can be changed to the non-latched (non-backed-up) area by
parameter setting.
*3. The characteristics of latch (backup) cannot be changed using parameters.
/FX /FX PLCs
3U 3UC
Latched (battery
General type
backed-up) type
M0 to M499 M500 to M1023
*1
500 points 524 points
Fixed latched (EEPROM
General type
backed-up) type
M0 to M383 M384 to M1535
384 points 1152 points
Fixed latched (EEPROM
General type
backed-up) type
M0 to M383 M384 to M511
384 points 128 points
/FX /FX PLCs
2N 2NC
Latched (battery
type backed-up) type
Battery backed-up EEPROM backed-up Capacitor backed-up
-
*3
-
*3
M500 to M1023 M1024 to M3071
*1 *2
524 points 2048 points
Fixed latched (battery
backed-up) type
M1024 to M7679
*2 *3
6656 points
General type
M1536 to M7679
*4
6144 points
General type
M512 to M1535
1024 points
→ Refer to the data communication manual.
Fixed latched (backed-up) type
M384 to M511
-
*3
128 points
M384 to M511
-
*3
128 points
-
*3
2 Devices in Detail
2.3 Auxiliary relay [M]
Special type
M8000 to M8511
512 points
Special type
M8000 to M8511
512 points
Special type
M8000 to M8511
512 points
Special type
M8000 to M8255
-
256 points
M512 to M1535
M8000 to M8255
*3
256 points
1024 points
M8000 to M8255
-
256 points
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