Sel 751A, Инструкция по эксплуатации

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7.5
Date Code 20100129 Instruction Manual SEL-751A Relay
Communications
Communications Interfaces
Dual Network Port Operation
The SEL-751A dual Ethernet port option has two network ports. Network port
failover mode enables the dual Ethernet port to operate as a single network
adapter with a primary and standby physical interface. You can connect the
two network ports to the same network or to different networks depending on
your specific Ethernet network architecture.
Failover Mode
In the failover mode operation, the relay determines the active port. To use
failover mode, proceed with the following steps.
Step 1. Set NETMODE to FAILOVER.
Step 2. Set FTIME to the desired network port failover time.
Step 3. Set NETPORT to the preferred network interface.
On startup the relay communicates via NETPORT (primary port) selected. If
the SEL-751A detects a link failure on the primary port, it activates the
standby port after the failover time, FTIME, elapses. If the link status on the
primary link returns to normal before the failover time expires, the failover
timer resets and uninterrupted operation continues on the primary network
port.
After failover, while communicating via standby port, the SEL-751A checks
the primary link periodically and continues checking until it detects a normal
link status. The relay continues to communicate via the standby port even after
the primary port returns to normal. The port of choice for communications is
reevaluated on change of settings or failure of the standby port or on reboot.
The relay returns to operation on the primary link under those conditions if it
detects a normal link status. When the active and backup links both fail, the
relay alternates checking for the link status of the primary and standby ports.
Unmanaged Switch Mode
If you have a network configuration where you want to use the relay as an
unmanaged switch, set NETMODE to SWITCHED. In this mode, both links
are enabled. The relay will respond to the messages received on either port.
All the messages received on one network port that are not addressed to the
relay will be transmitted out of the other port without any modifications. In
this mode NETPORT setting is ignored.
Fixed Connection Mode
If you have a single network and want to use only one network port, or if you
have both ports connected but want to force usage of only one port for various
reasons, set NETMODE to FIXED and set NETPORT to the port you want to
use. Only the selected network port operates and the other port is disabled.
Autonegotiation, Speed, and Duplex Mode
Single or dual copper Ethernet ports are capable of autonegotiating to
determine the link speed and duplex mode. This is accomplished by setting the
NETASPD and NETBSPD (network speed) to AUTO. Single or dual copper
ports can also be set to a specific speed to be able to apply them in networks
with older switch devices. However, the speed setting is ignored for fiber
Ethernet ports. The single and dual fiber Ethernet ports are fixed by the
hardware to work at 100 Mbps and full duplex mode.
NOTE:
If you change settings for the
host port in the relay and the standby
network port is active, the relay
resets and returns to operation on
the primary port.