Filter
Top Products
FX Series Programmable Controllers Devices in Detail 4
4-3
4.3 Auxiliary Relays
Device Mnemonic: M
Purpose: Internal programmable controller status flag
Alias: Auxiliary (coil/ relay/ contact/ flag)
M (coil/ relay/ contact /flag)
M (bit) device
Available forms: NO () and NC contacts and output coils ()
(see example device usage for references)
Devices numbered in: Decimal, i.e. M0 to M9, M10 to M19
Further uses: General stable state auxiliary relays - see page 4-3
Battery backed/ latched auxiliary relays - see page 4-4
Special diagnostic auxiliary relays - see page 4-5
Example device usage:
4.3.1 General Stable State Auxiliary Relays
• A number of auxiliary relays are used in the PLC. The coils of these relays are driven by
device contacts in the PLC in the same manner that the output relays are driven in the
program.
All auxiliary relays have a number of electronic NO and NC contacts which can be used by
the PLC as required. Note that these contacts cannot directly drive an external load. Only
output relays can be used to do this.
• For more information about device availability for individual PLC’s, please see chapter 8.
PLC FX1S FX1N FX2N FX2NC
General auxiliary
relays
384
(M0 - 383)
384
(M0 - 383)
500
(M0 - 499)
500
(M0 - 499)
Battery backed/
latched relays
128
(M384 - 511)
1152
(M384 -
1535)
2572
(M500 -
3071)
2572
(M500 -
3071)
Total available 512
1536 3072 3072
X0
X1
1
M507
2
M507
Available devices: