Tips on solving your PROFIBUS issues

10 June 2010

For most of us, there was a stage in our lives, while growing up, that we went through, that involved us being the doctor and one of our friends being a deathly sick patient. Although we as juvenile doctors had very little experience and what I mean by very little is nothing at all! Usually, we would prod and poke our “patients”, and after some time, they would bounce back to life and we would all proceed to go and play in the sun.

Much of what I have seen with PROFIBUS problems can be compared to our “doctor! doctor!” days. Let’s run through a short case study…a problem occurs onsite…”THE NETWORK HAS DIED,” what follows is an assault of prodding and poking until miraculously the network is up and running leaving all involved feeling exhilarated over a job well done but not knowing what was done to fix it.

Here are some practical tips on how to help solve your problem and hopefully leave you feeling a little bit less like you are alone in the dark:

  • The blind leading the blind
    If you know nothing about PROFIBUS, be honest and call an expert. I have never heard of anyone taking their Lamborghini Murcielago to a chop shop on the side of the road to get the exhaust spot welded.

  • Your weapon of choice
    Just like every good doctor has his/her stethoscope and surgical blade so too do you need yours. Unfortunately, most of the time people want to operate on their PROFIBUS network with a spoon and end up bludgeoning it to death. It is important to know the different options that you have when it comes to PROFIBUS diagnostic tools.

There are two different types of test tools, a physical line tester and a message/protocol analyser. Both are invaluable and are required to diagnose the full spectrum of problems that you may face. Some of the functionalities that you would want to look for in a message or protocol analyser are a bar graph, oscilloscope, message recording, reporting, trigger ability to start message recording when a fault occurs and preferably some master functionality.

  • Be doctor doc
    Know what the PROFIBUS installation requirements are. I can’t stress this enough, most faults are caused by bad installations and lack of knowledge. Some of the most common errors are incorrect terminations, and PROFIBUS cables cables tied to high-voltage lines running for hundreds of meters. Understanding what the “dos and don’ts” of PROFIBUS are will help you to identify where the problems lie.

In most cases, this should be evident by looking at these 5 tips and tricks.

  • Tip 1: Walk the line
    It’s important to know what is physically happening along the PROFIBUS cable. Things to look out for, terminations, stub lines, devices that don’t use D-Sub connectors because they may have a built-in termination switched on, location of high voltage lines, lengths of PROFIBUS cable, amount of devices in the segment and the type of cable used. Your problem may be found by simply looking at the network.
  • Tip 2: Best bar around
    Look at the bar graph to determine if any of the voltages are below the 2.5v threshold. If there is one device that has a low voltage level then focus your attention on that device. If multiple devices have low voltage levels then have a look at that specific segment. Unplug one device at a time to determine if that device may be causing the problem.

If the voltages all the voltages are fluctuating then there is a large chance that you have a dirty/floating earth or if one device’s voltage is fluctuating a lot then you might have a duplicate address on that device.

  • Tip 3: Catching the perfect wave
    Have a look at the signal waveforms, the waveform should be a square shape. A small spike may be present because you have plugged in the diagnostic tool. If the signal is not square and contains reflections (wave-like signals that die out then are repeated) or spikes, look for incorrect termination, over-termination or stub lines. These types of errors can easily be seen on an oscilloscope.

The advantage of using a PROFIBUS test tool oscilloscope is that you can look at the signal waveform for each slave as opposed to seeing all the waveforms and not knowing which device that specific signal originated from. Having a physical line PROFIBUS tester is helpful in these situations because you can test if the terminations are in the correct locations and not over or under-terminated.

  • Tip 4: Track and trace
    Use your message trace to record messages. This will give you an excellent idea of what the error may be. The two most common types of errors are broken messages and configuration errors. Broken messages are predominately caused by noise in the cable, breaking the messages or by slaves speaking at the same time causing message collisions. Configuration errors will not allow the device to enter data exchange or if the device was in data exchange and something broke in the device, then the device will fall out of data exchange.

  • Tip 5: Isolation
    In some situations, it may be difficult to find what the cause of the problem may be. Most modern PROFIBUS D-sub connectors break the outgoing line when the termination is switched on. This is extremely helpful and allows you to add one device to the network at a time. By doing this you should be able to find which device is causing the problems on the network.
  • Tip 6: I need backup
    If all else fails…give us a call we are more than willing to help you in your desperate time of need.

If you are looking for some PROFIBUS test tools, we sell and use them daily for audits and training.

<a href="https://blog.idx.co.za/author/idx-team/" target="_self">IDX Team</a>

IDX Team

Technical Team

The IDX team is a dynamic group of professionals dedicated to delivering cutting-edge industrial ICT solutions. With a focus on innovation, they leverage their expertise to streamline processes and drive efficiencies for your plant data.

Show your love!

Recent Posts

Driving Productivity with LineView Training

In light of our partnership with LineView Solutions, our team has taken up the opportunity to equip themselves with insights into the LineView system and its impact on the industry. “LineView is a production line monitoring and recording system that automatically...

Exciting New Launch: Onsite ProfiDay

IDX is excited to announce the launch of our onsite ProfiDay offering. This is available to all industries and companies that utilise PROFIBUS and/or PROFINET within their industrial communications systems. What is ProfiDAY? An exclusive onsite program offering...

Introducing our Partnership with LineView Solutions

We are excited to announce our partnership with LineView Solutions, a leading UK-based company specialising in smart factory solutions for optimising production processes. LineView developed a cutting-edge software suite designed to automatically gather data from the...

Optimise PROFIBUS and PROFINET Network Performance

As a field technician handling PROFIBUS and PROFINET systems, it is crucial to recognise the common errors that can result in costly downtime. From improper network configuration to neglecting regular maintenance, these mistakes can greatly affect system performance...

Delighted Customer Shares Experience

We recently assisted a client in rectifying damage to the Anybus ABC4090 Communicator caused by incorrect power usage onsite. We arranged for the device to be sent to HMS in Sweden for repairs, and they restored it before promptly returning it to us. Here are some...

Price Decrease on PROFIBUS Connectors

PROFIBUS connectors play a crucial role in industrial automation and data exchange systems by facilitating smooth communication between devices and networks. We are pleased to announce a significant price decrease on all our PROFIBUS connectors. Thanks to recent...

PROFIBUS Standards: Functional bonding and shielding

Electromagnetic Interference (EMI) and earthing issues can significantly impact the performance of your network. By following these six proven recommendations, you can ensure that your network is always up and running.

PROFIBUS Standards: Terminations

What is the Volts Direct Current (VDC) required for optimal operation of a PROFIBUS DP termination circuit? Get the answers you need in our latest video on PROFIBUS Standards: Terminations. Don't miss out on this essential knowledge to boost your system's performance!

PROFIBUS Standards: Segment Cable Lengths

Finding the perfect balance between PROFIBUS cable length and network speed is crucial. While longer cable segments might seem tempting, they can lead to signal degradation and slower speeds. Conversely, too short segments might limit your layout options. Striking the...

Sign up for our newsletter

Get exclusive updates and a sneak peek into our world every two months. Stay connected, stay informed.

Related Posts

Our expertise lies in establishing, maintaining, and leveraging plant data for business benefit. Through our innovative solutions, we work alongside you to streamline processes, enhance efficiency, and reduce costly downtime.

CONTACT US

Main: +27 (11) 548 9960
Sales: +27 (11) 548 9970

SOCIAL MEDIA

Copyright @2024 Industrial Data Xchange. All rights reserved.