Setting up an S7 connection using TCP/IP

The TCP/IP method of communication to the S7-300 and S7-400 PLC's via TCP/IP communication module uses the S7WIN, S7WINSP, S7NT, or S7NTSP protocol.

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.

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.

Rockwell Automation unveiled some significant additions to the Logix Control Platform at the Automation Fair event in Baltimore on Oct. 25, 2006. Further additions and improvements were detailed in a presentation on RSLogix5000 Version 16 as presented below.

A staple of any PLC instruction set is the timer. The most common type is the "On Timer" while its brother the "Off Timer" suffers from misunderstanding and neglect. There are quite a few PLC manufacturers (you know who you are) who simply do not offer an off timer instruction. This is a shame because they are so handy for keeping something else on (i.e. a fan or light) for a given period after something has turned off.

Developing and managing several different PLCs and HMIs can be a real burden on a PC or laptop.  The problems include:

• The different software packages can cause conflicts with each other.  Communication problems are a common example
• Memory gets loaded up with automatically started background services even if you're not using the programs.  This kind of bloat makes everything slower.
• Some packages don't uninstall well and leave behind a lot of files.
• Older legacy software may only run on older operating systems.

To remedy the situation there are some options:

This Siemens S7-300 PLC Trainer shows how easy it is to build a trainer or development stand using our PLC simulators. You won't find a better setup. Consider the advantages.

Here's a good example of our PLC simulators used on an Allen Bradley SLC-500 trainer.  I built this unit for a customer that does automation training.  This concept is easily adaptable so if you're interested in something like this then fell free to contact me.

General

1. What is MODBUS?

MODBUS is a commonly used industrial communications protocol. It allows the exchange of data between PLCs and computers. It was originally designed for Modicon (Schneider Electric) PLCs but has become widely used by many PLC manufacturers and industrial networks.

2. Why would I use MODBUS?

MODBUS is a common means of gathering data from many different sources for viewing operations, archiving and troubleshooting from a central remote location. It is widely used and a fairly simple protocol. Depending on the application a newer protocol may have more advantage.

Automation Direct's DirectSOFT5 programming software has a Tip of the Day feature. There's some good tips in there so I've reproduced them here for easier reading.

• The Online Status Bar is now an integrated part of the main Status Bar on the bottom of the application.