990XCP98000 SQUARE D, 990XCP98000 Datasheet - Page 94

• Manufacturer Part Number: 990XCP98000
• Description: QUANTUM CPU BATTERY FOR S
• Manufacturer: SQUARE D

Specifications of 990XCP98000

• Rohs Compliant: YES
• Battery Capacity: 1800mAh
• Battery Technology: Lithium
• Battery Voltage: 3V
• Battery Terminals: Connector
• Weight: 0.12lb

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Functions
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(continued)
Modicon
automation platform
Hot Standby system
Unity Pro
b
The majority of redundant PLC applications expect identical application programs on
both CPUs. To this end, a comparison is made of the application program in both
PLCs. It takes place immediately on power-up, and is repeated constantly while the
standby system remains active.
By default, the “Standby” PLC will disconnect itself from the standby system as soon
as a difference in program is detected. In order to maximize availability of the control
system, including during interventions on the application program, it is however
possible, via the configurator dialog box or via the Command Register, to authorize
the continued activity of the standby system with applications whose program code
and/or database are different.
b
When the second PLC is powered up, the content of the PLC memory is made
identical to that of the primary PLC automatically (Plug and Play) in a number of
cases. This is in particular true when this second PLC is empty. At the end of the
transfer, the standby system is active, the first PLC then takes the “Primary” role and
the second the “Standby” role.
The user can also request an upgrade via the mini dialog terminal that can be
accessed from the front panel of the “Primary” PLC, especially after a modification
has been made to the application. This operation on the mini-terminal can be
performed by a maintenance engineer, without needing to use a programming
terminal. This function is also available via a Command Register bit.
b
A Command Register bit, set if necessary from the configuration dialog box of the
Hot Standby system, is used for sequential upgrading of the operating systems of
both PLCs, while maintaining control of the process by the application program.
b
When the standby system changes over, the respective addresses of the equivalent
communication ports on the “Primary” and “Standby” PLCs are exchanged
automatically. This exchange of addresses is unconditional for Ethernet and
Modbus Plus
140 CPU 671 60 CPU.
This function for the automatic exchange of communication port addresses greatly
simplifies the task of the developer on supervisory control systems (HMI, SCADA,
etc.). In effect, a given address thus characterizes an “operational” PLC (“Primary”
or “Standby”) and not a physical PLC.
b
Irrespective of the I/O architectures used (RIO remote I/O or mixed I/O), the Hot
Standby system automatically manages the exchange mechanisms between the I/O
and the PLC performing the “Primary” function.
Functions (continued)
Monitoring of program discrepancies
Ensuring parity of the content of the PLC memories
Upgrading the operating systems
Automatic exchange of communication port addresses
Automatic exchange mechanisms during communication
™
™
ports. It occurs conditionally for the local Modbus port on the
software
®
Quantum
™