BASEstar^tm Open DAS
for Allen-Bradley Data Highway^tm
on OpenVMS^tm
Installation and User's Guide

The PLC-3 family supports the following addressing syntaxes:

• Data table addressing
• Extended addressing

Section 3.3.2.1 and Section 3.3.2.2 describe these addressing syntaxes.

3.3.2.1 PLC-3 Data Table Addressing

The structure of a legal data table address for the PLC-3 differs depending on the table that is being addressed. The PLC-3 supports the following data table sections:

I - Input
O - Output
C - Counter
T - Timer
A - ASCII
B - Binary
D - Decimal
F - Floating-Point
H - High-Order Integer
N - Integer
S - Status
P - Pointer

Figure 3-2 shows the structure of a legal I/O data table address for the PLC-3.

Table 3-8 shows examples of legal I/O data table addresses for the PLC-3.

Figure 3-2 PLC-3 I/O Data Table Address Format

Table 3-8 Example PLC-3 I/O Data Table Addresses

Example Address	MMS Type1	Description
I20	UNSIGNED_16	Input image rack 2 group 0 octal
I377	INTEGER_16	Input image rack 37 group 7 octal
I1:1777/17	BIT_STRING	Bit 17 of word 1777 octal in file 1 decimal
$O33:77/1	BIT_STRING	Bit 1 of word 77 octal in file 33 decimal
O99:167	INTEGER_16	Word 167 octal in file 99 decimal
I0	Array of 10 UNSIGNED_16	Ten words beginning at rack 0 group 0