Allen-Bradley MicroLogix 1400 User Manual

Publication 1766-RM001A-EN-P - October 2008
98 Programming Instructions Overview
Indirect Addressing Example
An equivalent example using indirect addressing is shown below. In place
of using the index register, S:24, the user can designate any other valid
word address as the indirect address. Multiple indirect addresses can be
used within an instruction.
The following ADD instruction uses an indirect address in the Source A
and Destination addresses. If the indirect offset value is 20 (stored in
N7:3), the controller uses the data stored at the base address plus the
indirect offset to perform to instruction.
In this example, the controller uses the following addresses:
Table 4.2
Operand Base Address Offset Value in N7:3 Working Address
Source A N7:0 20 N7:20
Destination N7:0 20 N15:20
Indirect Working
ADD
Add
Source A N7:[N7:3]
Source B 25
Dest N15:[N7:3]
ADD ADD
Add
Source A N7:20
Source B 25
Dest N15:20
ADD
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Allen-Bradley MicroLogix 1400 Specifications

General

Processor	32-bit
Expansion Modules	Up to 7 expansion I/O modules
Power Supply	24V DC or 120/240V AC
Programming Software	RSLogix 500
Communication Ports	Ethernet, RS-232/RS-485 combo port
Controller Type	Programmable Logic Controller (PLC)
Series	MicroLogix
Digital Outputs	12
Analog Inputs	6 (embedded)
Analog Outputs	2 (embedded)
High-Speed Counter	6 high-speed counters
Pulse Output	2 (embedded)
Ethernet Port	Yes