20
signed the next word(s) following the word(s) assigned to the previous Unit. If
there are any empty slots, no words will be assigned. Words are only as-
signed when a Unit is mounted; all empty slots are skipped. The number of
I/O words allocated to each type of Unit is shown below.
Unit
Words required
16-pt I/O Units
1 word
24- or 32-pt I/O Units
2 words
64-pt I/O Units
4 words
Interrupt Input Unit
1 word
Dummy I/O Unit
Set to 1, 2, or 4 words
Analog I/O Units
2 or 4 words
High-speed Counter Units
CT012 and CT041: 2 words; CT001: 4 words
MCR Units
4 words
PID Unit
4 words
I/O Interface Unit
None
Cam Positioner
2 or 4 words
ASCII Unit
2 or 4 words
Host Link Unit
None
PC Link Unit
None (assigned LR words)
SYSMAC LINK Unit
None (assigned LR and/or DM words)
SYSMAC NET Link Unit
None (assigned LR and/or DM words)
Remote I/O Master Unit
None*
Remote I/O Slave Unit
None*
I/O Link Unit
1 or 2 words
File Memory Unit
None
Position Control Units
2 or 4 words
I/O Control Unit
None
ID Sensor Unit
5 words
*Remote I/O Systems are described briefly below.
Once the word(s) assigned to a Unit has been determined, the use of individ-
ual bits in the word(s) is determined by the type of Unit. If the Unit is a Spe-
cial I/O Unit, I/O Link Unit, or Intelligent I/O Unit, each bit will have a dedi-
cated function. Refer to
Operation Manuals
for the relevant Units for details.
With I/O Units, bits within a word are assigned to terminals starting at the top
of the I/O Unit with bit 00 and going sequentially to the bottom. If the first Unit
on the left of the first Rack (CPU Rack for all but C2000H Duplex Systems;
CPU I/O Rack for C2000H Duplex Systems) is an Input Unit, the top termi-
nals (i.e., the top input point) will be assigned IR 00000, the next terminals,
IR 00001, and so forth for all of the terminals on the Unit. The allocation or-
IR Area
Section 3-3
