Rockwell Automation 1785-CHBM ControlNet PLC-5 Hot Backup System User Manual - Manual (Page 129)

Publication 1785-UM024B-EN-P - January 2003
v
N
network update time (NUT) The repetitive time interval in which data can be sent on a
ControlNet network. This interval represents the fixed time
interval for sending scheduled and unscheduled messages from
a ControlNet node. The network update time ranges from
2ms-100ms.
no control backup state When a valid backup configuration exists, but the PLC-5 is not in
Run mode, the PLC-5 ControlNet backup system is in the no
control backup state. Both the Primary and Secondary LED’s on
the 1785-CHBM cartridge are off when in this state.
P
passive switchover A condition in which the primary PLC-5 is not able to control the
switchover operation. This occurs when there is a power failure
in the primary chassis or a primary PLC-5 failure. See active
switchover.
phase 2 data crossload A data transfer from the primary PLC-5 to the secondary PLC-5 of
timer and counter accumulator values, PD structures and
user-defined values. If the data table structures are the same in
the primary and secondary PLC-5s, this data transfer occurs
automatically during qualification of the secondary. You can
also request a phase 2 data crossload on demand for the
secondary PLC-5 by writing a “1” into word 33 of the Backup
Configuration and Status file.
PLC Programmable Logic Controller
PLC-5 As used in this document, PLC-5 represents the PLC-5/40 and
PLC-5/80 ControlNet phase 1.5, series F programmable
controller that can be used in the ControlNet hot backup system.
primary backup state When a PLC-5 ControlNet backup system is in Run mode, and is
actively controlling all of the system outputs, it is in the primary
backup state. The Primary LED is green, either blinking or solid;
the Secondary LED is off.
primary PLC-5 The PLC-5 in a hot backup system that is in control of the system
outputs.