Allen Bradley

More in depth programming information and documentation is available at DO Supply covering a wider array of Allen-Bradley FAQ

Install and Test a MVI46-MCM Modbus Module for SLC-500

by Nugroho Budi from

The MVI46-MCM is a Modbus communication module provided by ProSoft Technology. The module can be installed in a SLC500 rack so it can communicate to other Modbus devices.

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Learn Ladder Logic with a Free Version of RSLogix 500 and RSEmulator 500

One of my most common questions is, “Where can I get a free download of RSLogix 500?”  For any serious development with SLC500 or MicroLogix there is no free option but there is a nice free option if you only want to learn and/or program a MicroLogix 1000 or 1100.  Programming a MicroLogix is very very similar to programming a SLC500 or in that case a PLC5 too. 

Allen Bradley offers as a free download a software package called RSLogix Micro Starter Lite which is essentially the same programming environment as RSLogix 500.  On top of that, they also offer RSLogix Emulate for free so that you don’t even need a PLC to run and test your ladder logic.  Keep reading and I’ll show you how to get the software and set it up.

RSLogix 5000 Add-On Instructions

by John Schop

One of the most powerful newer features of the RSLogix 5000 program is the ability to create Add-On Instructions. This allows a programmer to define an instruction that contains a commonly used function or algorithm (as a set of instructions), and use it as one instruction.

To illustrate how this works, I am going to create an instruction that operates a cylinder, and because I’m making an add-on instruction, I can use that same instruction to control any number of cylinders in my application

Connecting Excel to ControlLogix

by John Schop

Have you ever lost data in a CLX processor, because you downloaded new code? Unfortunately, when you donwload a program to a ControlLogix processor, you also download the values of the tags (variables).

A solution to this problem that could be useful, is an Excel sheet that reads and writes values to the ControlLogix processor using the DDE/OPC capabilities of RSLinx.

In this article, I will show you how to create one of these sheets for your projects.

Here's what you'll need:

User Defined Data Types (UDTs) and OOP

by John Schop

For years now, Object Oriented Programming paradigm (or OOP) has been a commonly used programming practice, and has of course found its way into industrial automation as well.

The Logix5000 Essential Manuals

The Allen Bradley Logix5000 family (ControlLogix, CompactLogix, FlexLogix, SoftLogix) has some very good manuals. If you are just starting out or need a refresher here are the key manuals and the order I would read them. If you have RSLogix 50000 installed then you will find some of these in the Help > Online Books menu. Revision 16 also has some great videos in the Learning Center.

An Introduction to RSLogix5000 Tags

Tags are the method for assigning and referencing memory locations in Allen Bradley Logix5000 controllers. No longer are there any physical addresses such as N7:0 or F8:7 which use symbols to describe them. These have been replaced with tags which are a pure text based addressing scheme. This is a departure from the more conventional ways of programming PLC’s, which includes Allen Bradley’s earlier line of PLC5 and SLC 500 controllers.

Kit - Allen Bradley CompactLogix 1769 Digital Input Simulator

Kit - Allen Bradley CompactLogix 1769 Digital Input Simulator

Everything you need to simulate inputs into an Allen Bradley CompactLogix 1769 digital input module.

Price: USD $74.99


  • If you are have trouble downloading a project even though you have privileges, make sure that you have the project and that you are online with the controller.
  • If you can't access routine source protection when security is enabled, ask your administrator to grant you "Routine: Modify Properties" to obtain access.
  • If your system uses FactoryTalk Security with RSLogix5000 software, version 16, software users can log into and log off of RSLogix 5000 software.

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Project Documentation

  • Comments in Structured Text are downloaded to the controller. This includes comments in Structured Text routines and embedded Structured Text in SFC routines.
  • You can print RSLogix 5000 views by clicking on the view and then pressing Ctrl+P or choosing Print from the File menu.
  • When you print FBD logic, the editor automatically makes the logic fit the page. A 2:1 ratio is generally readable. For example, set the FBD sheet size to 11 x 17 (B Size) and print on 81/2 x 11 size paper.

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