89
saia-pcd.com
Standby Controller
Eth 2.2 Eth 2.1
USB Eth1
Standby Controller
5
Switch cabinet
components
4
Consumer
data acquisition
3
Dedicated
room controllers
2
Operation
and monitoring
1
Automation
stations
The PCD3.M6880 standby controller has two independent processors (CPU0 and CPU1). Both processors have their own independent
PCD media (F, R, T, C, DB/TX).
The redundant CPU1 runs the redundant user program and controls the shared inputs/outputs of the PCD3.T668 remote I/Os.
The redundant programs in the primary and secondary PCD3.M6880s are identical. During normal operation, only the active PCD
runs the redundant program. CPU1‘s internal used PCD media (F, R, T, C, DB/TX) are transferred from the active to the standby PCD
via the Ethernet interface 2 (ETH2.x). In the event of a fault, the standby PCD takes over operation without interruption, and runs the
redundant program using the last process image from the active PCD.
Depending on requirements, the user programs of the main CPU0 can be different in the primary and secondary PCD3.M6880.
CPU0 has the same capabilities as a standard PCD (e.g. PCD3.M5560). Local I/Os in the PCD‘s slots, and the I/O expansion modules,
are controlled by CPU0. External systems and devices (SCADA systems, web browsers and other external devices) communicate
only with CPU0. CPU0‘s internal PCD media (F, R, T, C, DB) are not synchronized between the active and standby PCD.
CPU1‘s program cannot directly access the local IOs or CPU0‘s media (and vice versa). Data is exchanged between CPU0 and CPU1
using a data exchange mechanism. The data to be exchanged (PCD media) are define in global symbol files. This data is automatically
exchanged between CPU0 and CPU1 on each program cycle.
1.6.1
PCD3.M6880 Standby Controller
Architecture of the PCD3.M6880
1
Data Media Transfer (Exchange Range or/and CSF/FBox)
2
S-Bus GWY CPU0 to CPU1 (2 different S-Bus address)
3
Redundant program on CPU1 runs only if active. Same program on both PCDs.
4
Non-redundant program can be different in both PCDs.
Ethernet RIO
PCD3.T668
SCADA and/or
other systems
Standby controller PCD3.M6880
Redundant
(CPU1)
4
Non Red.
Program
IO
Flash
BACnet
LON
Com
3
Red.
Program
1
Media
2
S-Bus
Main (CPU0)
PCD3.M6880
