
12
2-1 Indicators
CPU indicators provide visual information on the general operation of the PC.
Although not substitutes for proper error programming using the flags and
other error indicators provided in the data areas of memory, these indicators
provide ready confirmation of proper operation.
CPU indicators are shown below and are described in the following table.
Indicator Function
POWER Lights when power is supplied to the CPU.
RUN Lights when the CPU is operating normally.
ALARM/ERROR ALARM: Flashes when a non-fatal error is discovered in error
diagnosis operations. PC operation will continue.
ERROR:Lights when a fatal error is discovered in error diagnosis
operations. When this indicator lights, the RUN indicator will go
off, CPU operation will be stopped, and all outputs from the PC
will be turned OFF.
OUT INHIBIT Lights when the Output OFF Bit, SR 25215, is turned ON. All
outputs from the PC will be turned OFF.
RUN POWER
ALARM/ERROR
OUT INHIBIT
2-2 PC Configuration
The basic PC configuration consists of two types of Rack: a CPU Rack and
Expansion I/O Racks. 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 illustra-
tion of these Racks is provided in 3-3 IR Area. A third type of Rack, called a
Slave Rack, can be used when the PC is provided with a Remote I/O Sys-
tem.
A C200H CPU Rack consists of four components: (1) The CPU Backplane, to
which the CPU and other Units are mounted. (2) The CPU, which executes
the program and controls the PC. (3) Other Units, such as I/O Units, Special
I/O Units, and Link Units, which provide the physical I/O terminals corre-
sponding to I/O points.
A C200H CPU Rack can be used alone or it can be connected to other
Racks to provide additional I/O points. The CPU Rack provides three, five, or
eight slots to which these other Units can be mounted depending on the
backplane used.
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
CPU Indicators
CPU Racks
Expansion I/O Racks
PC Configuration Section 2-2
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