User Manual

SGD-SB2025NT-TUM, Part 2
Jan 12 Page 72 DIAGNOSTICS
For example, if the Secondary TM has taken over the duties of the Primary TM in position two in
the table, then loss of the Primary TM in position three will not result in any change in the function
of the Secondary TM and the Solar channel(s) operated by Primary TM number three will be
unavailable. However, if at this time Primary TM number two is brought back into service (online),
the Secondary TM will relinquish the duties of Primary TM number two and take over for Primary
TM number three. If, in this example situation, Primary TM number one (first position in the table)
is lost, the Secondary TM will cease the duties for any other Primary TM and take over for Primary
TM number one since it has highest priority.
8.1.3 Changeover Operation
Loss of the data exchange between one of the Primary TMs and the Secondary TM will cause the
Secondary TM to assume that that particular Primary TM is unavailable; consequently, the
Secondary TM will start sending data packets to every NI under the jurisdiction of the failed
Primary TM. Since every NI sends its data packets to the IP address that is taken from the source
of the incoming data packets, the changeover to a Secondary TM results in NIs ‘connecting’ to the
active TM simply by changing the destination address of their outgoing packets.
In this way, control of the system will changeover to the Secondary TM and this usually occurs
within 5 seconds. However, this time may be extended according to the network design and the
nature of the failure. The status quo will continue indefinitely until the data exchange between
Primary and Secondary resumes, at which point, the Secondary TM will cease to send data
packets to the NIs and thereby relinquishes control back to the Primary TM. The NIs will now
receive data packets from the Primary TM, which will change the destination address back to that
of the Primary TM and normal operation will return.
8.2 C ONFIGURING FOR D UPLICATION
Attempting to select a duplicated option on a TM that does not have the facility enabled in the
‘Facility Key’ will fail. The three duplication options for a TM unit are detailed below.
8.2.1 Unduplicated
This option is the default stand alone mode of operation of the TM. In this configuration the TM is
effectively operating as a Primary TM but not configured for the presence of a Secondary TM.
8.2.2 Duplicated (Primary)
This option specifies that this TM will be operating in a duplicated environment and that it is
designated as a Primary TM.
To configure a TM to operate as a Primary, carry out the following:
1. Open the TM Status panel and select the ‘Network’ button (see Section 4.3 – Setting the
TM IP Address ). The ‘TM Network Setup’ page shown in part in Figure 63 overleaf will
open.
2. On the ‘TM Network Setup’ page, carry out the following:
2.1. Select the ‘Eng’ button.
2.2. Using the drop-down list, set the TM Duplication to ‘Duplicated (Primary)’.
2.3. Tick the ‘IP Address 1’ box, which is now active.
2.4. Enter the IP address of the Secondary TM.
2.5. Select the ‘Apply’ and then the ‘Close’ buttons.