330
I/O Link Units for CPM1A and CPM2A
Section 5-9
Terminal Arrangement
and Wiring
The following diagram shows the terminal arrangement and wiring for the
CPM1A-SRT21.
When viewed from the CPM1A or CPM2A CPU Unit, the 8 input and 8 output
points under the CompoBus/S I/O Link Unit are allocated to the I/O memory
(input and output bits) of the CPU Unit, as is the case with Expansion I/O
Units. However, actual I/O operation is not performed for the I/O memory of
the CPM1A or CPM2A CPU Unit, but it is performed for the I/O memory of the
CPU Unit in which the CompoBus/S Master Unit is mounted.
Allocation to CPM1A/
CPM2A I/O Bits
As with other Expansion I/O Units for the CPM1A and CPM2A, both input and
output bits for the I/O Link Unit start with the word following the last word allo-
cated to the CPM1A or CPM2A CPU Unit or the previous Expansion I/O Unit
to which it is connected. If the last input word allocated to the CPM1A/CPM2A
CPU Unit or the previous Expansion Unit is word m, and the last output word
allocated to that Unit is word n, word allocations are as shown in the following
figure.
For example, an I/O Link Unit for CPM1A/CPM2A can be connected to the
first 30-point I/O CPM2A CPU Unit as shown in the following figure.
CompoBus/S
communications
*1: Not used
BS
+
BS
–
BD
H
BD
L
BD H
BD L
1
3
2
4
*1
*1
CPM1A-SRT21 I/O Link
Unit for CPM1A/CPM2A
CompoBus/S Master Unit
(or SRM1 CompoBus/S
Master Control Unit or
CPM2C-S CPU Unit)
CPM1A/CPM2A
CPU Unit
CompoBus/S Communications Cable
(Special Flat Cable or VCTF cable)
Bits 00 to 07 of
word n+1
I/O Link Unit for CPM1A/CPM2A
8 input points
8 output points
Bits 00 to 07 of
word m+1
Input number
Output number
30-point I/O
CPU Unit
Link Unit for
CPM1A/CPM2A
IR 002
IR 012
IR 000
IR 001
IR 010
IR 011