Allen-Bradley SLC 500 - Logical Addressing for Control Block Structures

Addressing Reference
SLC 500 Family of Programmable Controllers
19
The recommended default file for control block structures is file 6 of the
data table. This file accommodates up to 256 control block structures. If
your application requires more than 256 control block structures, specify
one or more files (10 – 255) in the user-defined area of the data table in
addition to file 6.
Each control block structure consists of three words. You can address a
control block structure in its entirety or you can address any particular
member of a structure individually.
Figure 19
Logical Addressing for Control Block Structures
File Type
R = Control
Member Mnemonic*
See Table P
Structure Number
0 – 255 decimal
Logical Address Identifier
File Separator
Member Mnemonic Separator*
$ R 6 : 123 .ACC
File Number
6 or
10 – 255 decimal
*Required only if addressing to the member level.
Figure 20
Bit Map of the Control Block Structure
1514131211109876543 2 10
EN RESERVED
LEN
Word 0
Word 1
Word 2
POS
EU DN EM ER IN
UL
FD
Logical Addressing for
Control Block Structures