2
1-1
Nomenclature
This section gives the names and functions of the various components of
P-type PCs and the basic Units with which they can be combined in a
System.
1-1-1
CPUs
In the diagram below, the C28P is shown as a representative model. Refer to
Appendix A Standard Models
for your model’s exact specifications.
Power supply Ground
Outputs
Indicators
CPU,
Expansion I/O
Unit, Analog
Timer Unit,
Analog I/O
Unit, or I/O
Link Unit
connector
24-VDC output
Peripheral connector
Inputs
High-speed counter
(HDM(98)
–
) inputs
EPROM socket,
DIP switch
High-speed Counter
When the high-speed counter (HDM(98)) is not being used, the two
high-speed counter input terminals can be used as normal DC input termi-
nals. Their ON/OFF response time, however, will be shorter (0.15 ms max.).
Regardless of whether or not the high-speed counter command is being
used, DIP switch pins 7 and 8 must be off whenever the hardware reset is
not being used.
Indicators
The diagram below shows the functions of the various indicators, taking the
C20P as an example.
8 9 10 11
0 1 2 3 4 5 6 7
OUTPUT 5 CH
POWER
RUN
ALARM
ERROR
INPUT 0 CH
OUTPUT: Shows whether the output is ON or OFF.
POWER: Stays lit while power is turned on to the
PC.
RUN: Stays lit while the PC is operating normally.
ALARM: Blinks during battery abnormality or scan
time overrun. At this time PC operation will be
intermittent.
ERROR: Lights when self-diagnosis detects an
abnormality. The PC will stop operating.
INPUT: Shows whether the input is ON or OFF.
0 1 2 3 4 5 6 7
Memory
Each of the C-series P-type PCs is provided with a built-in RAM (random-ac-
cess memory), as well as a ROM (read-only memory) chip socket. Either
may be used with ease. It is recommended to use the RAM for programming
and, when the program is completed, to save it in a ROM chip for protection.
The memory capacity in either case is 1,194 addresses.
Nomenclature
Section 1-1
