15.37
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Communications Interfaces
SEL Distributed Port Switch Protocol (LMD)
Set the RX_ID of the local relay to match the TX_ID of the remote relay. In a
three-terminal case, Relay X transmits to Relay Y, Relay Y transmits to Relay Z,
and Relay Z transmits to Relay X. Table 15.27 lists the M
IRRORED BITS commu-
nications ID settings for Relays X, Y, and Z.
SEL Distributed Port Switch Protocol (LMD)
SEL Distributed Port Switch Protocol (LMD) permits multiple devices to share a
common communications channel. This protocol is appropriate for low-cost,
low-speed port switching applications where updating a real-time database is not
a requirement. The relay does not have built in LMD protocol, but you can con-
nect this relay to an SEL-2885 EIA-232/485 Protocol Converter and connect the
SEL-2885 to an EIA-485 multidrop network. See the SEL-2885 EIA-232 to
MBNUMAN Number of analog data channels
(hidden and set to 0 if MBNUM := 7 or 8)
0–n,
n = 7–MBNUM
MBANA1
c
Selection for analog Channel 1 Analog quantity label
MBANA2
c
Selection for analog Channel 2 Analog quantity label
MBANA3
c
Selection for analog Channel 3 Analog quantity label
MBANA4
c
Selection for analog Channel 4 Analog quantity label
MBANA5
c
Selection for analog Channel 5 Analog quantity label
MBANA6
c
Selection for analog Channel 6 Analog quantity label
MBANA7
c
Selection for analog Channel 7 Analog quantity label
MBNUMVT Number of virtual terminal channels OFF, 0–n,
n = 7–MBNUM–MBNUMAN
a
Must be P for connections to devices that are not SEL-400 series relays.
b
Hidden based on MBNUM setting.
c
Hidden based on MBNUMAN setting.
Ta b l e 1 5. 26 M IRRORED BITS Communications Message Transmission Period
Speed in Bits
per Second
TXMODE := NORMAL
MBT := N
TXMODE := PACED
MBT := N
MBT :=Y
38400 1.0 ms 3.0 ms N/A
19200 2.0 ms 3.0 ms N/A
9600 4.0 ms 4.0 ms 7.0 ms
4800 8.0 ms 8.0 ms N/A
Ta b l e 1 5. 27 M
IRRORED BITS Communications ID Settings for Three-Terminal
Application
Relay TX_ID RX_ID
X1 3
Y2 1
Z32
Ta b l e 1 5. 25 M
IRRORED BITS Communications Protocol Settings (Sheet 2 of 2)
Name Description Range
To Next Page
Loading...
