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Remote I/O
4-2
Remote I/O
34
The following figure shows the word allocation for a fully expanded C200H with
three 8-slot Backplanes.
word
word
word
000
001
002
word
word
word
010
011
012
word
word
word
020
021
022
There are limits to how long the normal wiring between the PC and its Expansion
I/O Racks can be. A Remote I/O Unit can extend this distance greatly, so that the
PC and its Expansion I/O Racks can even be located in separate buildings.
There are two types of Remote I/O Systems, optical and wired.
By locating a Rack farther from the CPU Rack, a Remote I/O System eliminates
the time and mess in wiring (or changing wiring) to many devices that are sepa-
rated from the CPU Rack. Although all I/O points must ultimately be wired indi-
vidually, the question is one of distance: Do you want to wire dozens of terminals
all the way across a factory complex or do you want to run a single cable for most
of the distance and then wire individual terminals locally? A PC with an Expan-
sion I/O System is called an Expanded PC.
I/O words 100 through 199 and DM words 1000 through 1999 are allocated to
Special I/O Units. There are limitations to the number and model of Special I/O
Units that can be mounted to a Remote I/O Slave Rack. Provided no other mod-
els of Special I/O Units are mounted to a Remote I/O Slave Rack, the maximum
number of Special I/O Units that can be mounted is shown below for each model.
Group
A
High-speed Counter, Position Control
(NC111/NC112), ASCII, Analog I/O, ID Sensor,
Fuzzy Logic Unit
B
High-density and Mixed I/O, Cam Positioner,
Temperature Control, PID Control, Heat/Cool
Temperature Control
C
Temperature Sensor, Voice
D
Position Control (NC221)
When using a combination of A, B, C, and D Units on a Remote I/O Slave Rack,
the number of each model of Unit being used must satisfy the following two for-
mulas.
3A + B + C + 6D
A + B + C + D
word
word
word
005
003
004
word
word
word
013
014
015
word
word
word
025
023
024
Units
12
8
Section
4-2
word
word
CPU
006
007
word
word
Power
016
017
Supply
word
word
Power
026
027
Supply
Total number
4 Units
8 Units
6 Units
2 Units
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