Woodward EGCP-2 - Figure 4-13. a New Master Takes Over-Single Unit Operating on the Isolated Bus

Manual 26086 EGCP-2 Engine Generator Control Package
Woodward 89
Within a 5 minute period the sequencing screen on any unit will reflect the
change of master from unit one to unit two.
The system load is at a level somewhere between 25 and 65 percent, at which
no slave units are sequenced on or off line.
MAINS
NETWORK ADDRESS #2
ADDRESS: 1 2 3
MASTER SEQUENCING SCREEN
MAINS FAILURE DETECTED
Or Run With Load and No Parallel
Application
SYSTEM LOAD = 35%
MASTER 2
NEXT ON 3
NEXT OFF 1
PRIORITY 2 1 3
OPER. X X
G G
NETWORK ADDRESS #1
NETWORK PRIORITY #2
G
NETWORK ADDRESS #3
NETWORK PRIORITY #3
NETWORK PRIORITY #1
VIS-118
00-04-27
Figure 4-13. A New Master Takes Over—Single Unit Operating on the Isolated
Bus
When the sequencing screen displays the new master, the new master engine
will begin its start sequence. The new master must start and go on line in order
to take over its new role as master, which means to be in control of the load, and
of the sequencing control of the slave units.
The new master (Network Address 2) will start and parallel to the previous
master (Network Address 1). Load control will be isochronous load sharing
between the two units. See Figure 4-13. If the system load is greater than 25%,
then both units will remain on line. If the system load drops below 25%, then the
new master (Network Address 2) will sequence the slave (Network Address 1)
off line.
The new master has fully established itself on the network as the Master.
The above actions take place simply by changing the priority of any given unit so
that that unit is the New Master. As long as the unit is in auto mode, configured
for multiple unit operation and attached to the network, it will automatically
transfer itself to the Master Position.
Units operating in Auto with the Run with Load discrete input closed will
effectively transfer, or recognize the transfer of master units. However, being in
an auto and run with load mode, those particular units cannot be sequenced off
line by the master control.
If a unit is not in auto mode, or is configured for single unit operation, or is not
attached to the RS-485 network, then no transfer of master can occur.