Pc Configuration - Omron SYSMAC C2000H Operation Manual

PC Configuration

2-2 PC Configuration
CPU Racks
CPU I/O Racks
Expansion I/O Racks
12
The basic PC configuration consists of either two or three types of Rack: a
CPU Rack and Expansion I/O Racks for C2000H Simplex Systems and the
C1000H, and a CPU Rack, a CPU I/O Rack, and Expansion I/O Racks for
C2000H Duplex Systems. The Expansion I/O Racks are not a required part
of the basic system. They are used to increase the number of I/O points. An
illustration of these Racks is provided in 3-2 IR Area. A fourth type of Rack,
called a Slave Rack, can be used when the PC is provided with a Remote I/O
System.
A C2000H Simplex CPU Rack or C1000H CPU Rack consists of four compo-
nents: (1) The CPU Backplane, to which the CPU, the Power Supply, and
other Units are mounted. (2) The CPU, which executes the program and con-
trols the PC. (3) Other Units, such as I/O Units, Special I/O Units, Link Units,
and Intelligent I/O Units, which provide the physical I/O terminals correspond-
ing to I/O points. (4) The Power Supply, which provides power to the CPU
Rack.
A C2000H Simplex or C1000H CPU Rack can be used alone or it can be
connected to other Racks to provide additional I/O points. The C1000H CPU
Rack provides five or eight slots to which these other Units can be mounted
depending on the backplane used; the C2000H Simplex CPU Rack provides
six slots.
A C2000H Duplex CPU Rack Consists of a Duplex CPU Backplane, two
CPUs connected by a Duplex Unit, and a Power Supply. A Duplex CPU Rack
is completely filled by these Units and does not provide any slots for other
Units.
In a Duplex System, one of the two CPUs is active and the other is on
standby as long as both are operating normally. Both CPUs must contain the
same size and type of Memory Unit, and the same program. If the active
CPU fails to operate normally, the standby CPU takes control with simplex
operation until normal duplex operation can be restored. If an error occurs in
the standby CPU or in the Duplex Unit, the active CPU switches to simplex
operation. The Duplex Unit coordinates these processes.
To provide slots for other Units in a C2000H Duplex System, a CPU I/O Rack
is connected to the CPU Rack. The CPU I/O Rack is built on a I/O Back-
plane, which provides eight slots for other Units. In a Duplex System, one
CPU Rack and one CPU I/O Rack are used in a pair. The CPU has no
means of sending and receiving I/O signals without an I/O Rack. The I/O
Rack is always connected to a C2000H Duplex CPU via the connectors on
the Backplanes, allowing communication between the two Racks.
An Expansion I/O Rack can be thought of as an extension of the PC because
it provides additional slots to which other Units can be mounted. It is built
onto an Expansion I/O Backplane to which a Power Supply and up to eight
other Units are mounted.
An I/O Interface Unit is also mounted to any Expansion I/O Rack to interface
the Rack to the CPU Rack. Also, an I/O Control Unit must be mounted to any
C1000H or C2000H Simplex CPU Rack to which one or more Expansion I/O
Racks are mounted. In a C2000H Duplex System the I/O Control Unit is
mounted to the CPU I/O Rack.
An Expansion I/O Rack is always connected to the CPU via the connectors
on the Backplanes, allowing communication between the two Racks. In a
Section 2-2