Internal Relay (M); Latch Relay (L); Link Relay (B) - Mitsubishi Electric L02SCPU User's Manual And Reference

5.2.3

Internal relay (M)

The internal relay (M) is a device for auxiliary relays used in the CPU module. All of the internal relay are set to off
when:
• the CPU module is powered off and then on,
• the CPU module is reset, or
• the latch clear is executed. ( Page 88, Section 3.4)
The internal relay cannot be latched (data retention during power failure). Use the latch relay (L) when latch is required.
( Page 294, Section 5.2.4)
5.2.4

Latch relay (L)

The latch relay (L) is a device for auxiliary relays that can be latched inside the CPU module. During power failure,
on/off information are retained by the battery in the CPU module. The previous on/off information are retained even
after performing the following to the CPU module.
• Power OFFON
• Reset
The latch relay is turned off by the latch clear operation.
Scan time is prolonged when the latch relay is used. ( Page 353, Appendix 1.2)
5.2.5

Link relay (B)

The link relay is an internal relay whose point is input in hexadecimal. In the range where the network parameters are
not set, this relay can be used as an internal relay or a latch relay.
• The range where a link relay is not latched: Same as the range for an internal relay
• The range where a link relay is latched: Same as the range for a latch relay
When using a link device in the network module by using the points of the link register in the CPU module (default: 8192
points) or greater, change the points setting of the link register in the "Device" of the "PLC Parameter".
294