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Creating I/O Tables Section 8-2
Unit Check
When this method is used, the registered I/O tables are compared with the
actual I/O at startup. If they do not agree, A40110 will turn ON to indicate an
I/O setting error and operation will not be possible.
Checking I/O Allocation Status
The I/O allocation status can be checked in A260. If A260 contain 0000 hex,
automatic I/O allocation at startup is being used. If A260 contains BBBB hex,
user-set I/O allocations are being used.
■ Changes in I/O Allocation Status
You cannot return to automatic I/O allocation at startup by using the Program-
ming Console. To return to automation I/O allocation, the I/O tables must be
deleted from the CPU Unit using the CX-Programmer. When the I/O tables
are deleted, all settings for first words for Racks will also be deleted.
Precautions when
Changing I/O Allocation
Status
The I/O allocation status will change when one of these three operations are
performed.
1. Automatic transfer at startup
CHG
000000 I/O TBL
WRIT ????
9
7
1 3
000000 I/O TBL
WRIT 9713
WRITE
000000CPU BU ST?
0:CLR 1:KEEP
0
1
000000 I/O TBL
WRIT OK
CLR
000000 CT00
Address Name Contents
A260 I/O Allocations Status 0000 hex: Automatic I/O Allocation at Startup
BBBB hex: User-set I/O Allocation
Default setting:
Automatic I/O Allocation at Startup
I/O tables deleted from CPU Unit
using the CX-Programmer
User-set I/O Allocations
(A260: BBBB hex)
I/O tables created from Programming Device
I/O tables downloaded from CX-Programmer
Parameter file (.STD) transferred to CPU Unit
I/O tables are created every time power is turned
ON based on Units actually connected in PLC.
I/O tables are not verified.
Operation is performed according to the I/O tables
transferred to the CPU Unit using one of the above
three methods.
The registered I/O tables are verified against the I/O
Units that are actually connected in the PLC.
Automatic I/O Allocation
at Startup
(A260: 0000 hex)
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