In this article we will use Wago’s 750-333 Profibus Coupler and connect it to Siemens’ S7-315DP to create a Profibus DP network.

Let’s Start!

750−333

This is Layout of a 750-333.

D-Sub Connector

This is the Pin for Wago’s D-SUB Connector.

LED

The LEDs on the 750-333 allow you to check the current module status.

Field bus Status

LED	Color	Description
RUN	GREEN	Communication between PROFIBUS Master and Coupler is normal.
BF	RED	Indicates whether the PROFIBUS communication function is normal.
DIA	RED	Indicates the diagnostic status of the extension
BUS	RED	PROFIBUS indicates parameterization and Configuration errors

Node Status

LED	Color	Description
I/O	GREEN/RED/ORANGE	Indicates the operating status of the Node

Supply Voltage

LED	Color	Description
A	GREEN	Indicates the power supply status of the System
B/C	GREEN	Indicates the power supply status of Power Jumper

Rotary Station Address

The 750-333 sets the Node address from two Rotary Switches. For example, if x1 is set to 3 and x10 is set to 2, the address of 750-333 will be 23.

System Data

Flow

This is the internal flow of the 750-333: upon Running Up or Reset, the 750-333 initializes and compares the current Configuration with the connected IO module. (The LED will then flash red.) If there are no errors, the 750-333 will initialize and compare the current Configuration with the connected IO module.

>If there are no errors, the 750-333 will switch to “Fieldbus Start Mode” and the RUN LED will flash green.

>If there is an error, the 750-333 will flash the I/O LED red.

Baisc

The 750-333 can mix digital inputs, outputs, and Function Modules and uses K-BUS to exchange Process Data and Fieldbus Coupler.

Note that some IO modules cannot be used depending on the firmware of the Fieldbus Coupler.

Be Careful!

There are restrictions not only on the 750-333, but also on the Controller and Coupler firmware versions. For example, the firmware of the 750-333 that using this time is V17, I cannot use the 750-471’s 4-point analog input with FW20 at a minimum.

In/Output Data

Regarding mapping, the 750-333 can exchange up to 244Bytes of process data with the Master via Profibus. In fact, the IO Module settings installed on the 750-333 must be imported into the Profibus Master software (in this case, Step7 V5.7 Classic) by using the GSD file.

GSD File?

To build a PROFIBUS DP network, a GSD File (General Station Description) provided by the manufacturer is required, which defines the functions of the Profibus Slave.

For example, the 750-333 used in this project can be downloaded from WAGO’s website.

About Profibus

Let us introduce Profibus, the Open Fieldbus according to DIN 19 245. The Profibus DP (DP stands for Deecentralized Peripheral) is a version of Profibus that is easy to build and allows efficient data exchange with PLCs and PCs.

The DP System includes a DP Master and up to 125 Slaves,and asynchronous communication is also supported from PROFIBUS DP/V1.

ThePROFIBUS communication speeds range from 9.6 kBaud to 12 MBaud.

DP Master

DP Maseter is responsible for data exchange and monitoring with DP slave via PROFIBUS DP.

DP Slave

This device is linked to the PROFIBUS DP Network and receives output data from the Master and feeds back input data.

Download GSD Files

First, download the 750-333 GSD File from WAGO at the following Link.

https://www.wago.com/global/i-o-systems/fieldbus-coupler-profibus-dp/p/750-333#downloads

A Zip File like this should have been downloaded.

Which One?

Since we will be using 750-333, we will unzip the Folder 0750-0333.

But there are still many Folders inside. Which one should I use?

Do you see numbers like 33131720 in the 750-333 Profibus Coupler?

Actually, as I mentioned in the ReadME File, that number is the Coupler’s production information.

As for the Format,

WW YY SW HW FWL -xh1h2h3 in,

WW=weeks manufactured

YY=Year manufactured

SW=Software Version

HW=Hardware Version

FWL=Firmware Loader Version

-xh1h2h3=Internal number

This time on my 750-333 it is 33131720, so WW=33, YY=13, SW=17, HW=20.

That means it was manufactured in the 33rd week of 2013, Software Version is 17, Hardware Version is 20, and with that much information, I know what Folder to use.

If you look at the Folder again, you will see WWYYY[23…]. The naming rule for the folder is xxxx-xh1h2h3.

You don’t have to worry about WWYY because it is the Week of Manufacture and Year, but the [23…] indicates its Software Version. In other words, my Coupler is Version 17, so WWYY[17..]. Folder of xxxx-xh1h2h3 is used.

Implementation

Now let’s actually build a Profibus Network with Siemens’ S7-315DP and Wago 750-333.

Add S7-300 Station

Start SIMATIC Manager and click on Project>Right click>Insert New Object>SIMATIC 300 Station.

A new S7-300 Station has been added.

Install GSD Files

Next we will add the GSD Files; click on the Hardware button.

Options>Install GSD File.

Select “From the directory” for Install GSD File and click the Browse button.

If you expand xxxx-xh1h2h3 that downloaded from Wago HP, you will find 3 Folders, Standard/Extended/Advanced, and this time you will install the Standard GSD File.