# BASEstartm Open DAS
for Allen-Bradley Data Highwaytm
on Tru64tm UNIX
Installation and User's Guide

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## 3.3.3 PLC-5 Addressing Syntax and Supported Data Types

This section describes legal data table addresses and data types for the 1785 PLC-5 family. For information on addresses and supported data types for the PLC-5/250 PLC, refer to Section 3.3.4.

The structure of a legal data table address for the PLC-5 differs depending on the table that is being addressed. The PLC-5 supports the following data table sections:

> I - Input
> O - Output
> S - Status
> B - Binary
> T - Timer
> C - Counter
> R - Control
> N - Integer
> F - Floating-Point
> A - ASCII
> D - Decimal
> ST - String
> SC - SFC Status
> BT - Block-Transfer Control
> TD - Token Data
> PD - PID Control
> MG - Message Control

Figure 3-10 shows the structure of a legal I/O data table address for the PLC-5.

Table 3-13 shows examples of legal I/O data table addresses for the PLC-5.

Figure 3-10 PLC-5 I/O Data Table Address Format

Table 3-13 Example PLC-5 I/O Data Table Addresses
Example Address | MMS Type1 | Description
--- | --- | ---
I:20 | UNSIGNED_16 | Input image rack 2 group 0 octal
I:277 | INTEGER_16 | Input image rack 27 group 7 octal
I:177/17 | BIT_STRING | Bit 17 of rack 17 group 7 octal
$O:77/1 | BIT_STRING | Bit 1 of rack 7 group 7 octal
I:0 | Array of 10 UNSIGNED_16 | Ten words beginning at rack 0 group 0

1Arrays are supported. Structures are not supported. Variable size arrays are not supported.

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