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What are Electrostatic Discharge common EMC solutions?

Common Solutions | EMC Bayswater

Electrostatic Discharge common EMC solutions

 

In this article, EMC Bayswater discusses typical electrostatic discharge (ESD) problems and common solutions. Electrostatic discharge (ESD) is a common phenomenon that is encountered on an everyday basis by many of us. It is the sudden flow of electrical energy between two objects of differing electrical potential (or charge).

ESD is essentially a lightning bolt on a very small scale and, like a lightning bolt, the electrical energy will try to find a low impedance path to ground in order to equalize the electrical potential. Anybody who has walked across a carpeted floor and touched a metal doorknob may have felt or even seen a small spark jump from their hand to the metal doorknob.

Another very common occurrence is getting out of your car and touching a grounded path. It is worth noting that the human body is only sensitive to electrostatic discharges greater than around 2000-3000 Volts but higher voltages can easily be generated in real life. While in most cases this kind of phenomenon is not hazardous to humans aside from a surprise jolt and a little discomfort, our electronic devices can be affected in more severe ways. The purpose of electrostatic discharge testing of electrical products is to evaluate their ability to withstand these events.

Electrostatic Discharge | EMC Bayswater

When an electrostatic discharge current travels through an electronic device it will try to find a low impedance path to ground. While in some cases this may be through the chassis of the device, it is not at all uncommon for the current to travel through sensitive electronic circuitry with enough energy to permanently damage components such as Integrated Circuits (ICs), transistors, diodes in some cases passive components such as high precision resistors. An electrostatic discharge can also create local but intense electromagnetic fields which may couple into nearby circuitry and disrupt signals. Some common ways to mitigate the effects of electrostatic discharge phenomena include:

  • Insulation
  • Proper grounding
  • Suppression/filtering
  • Galvanic isolation
  • Firmware

Insulation

A common and effective way to minimize the effects of ESD on a device is to stop discharges from occurring in the first place. Using plastic with a high breakdown voltage and sufficient spacing between touchable points and conductors may provide enough insulation to prevent an ESD event from occurring.

Insulation is effective on weak points such as switches, LEDs, rotary controllers, displays and connector shields usually where the enclosure integrity is jeopardized. In some cases, entire circuits or parts of circuits can be encapsulated in a potting compound such as a resin or silicone.

Proper Grounding

Unlike insulation, which provides no path for ESD currents, proper grounding allows for a low impedance path to ground. Metallic connector shields and screws should have a low impedance connection to the metallic chassis which in turn should be connected to the protective earth or functional earth via a low impedance connection.

This allows the electrical energy to find a path to the ground without traveling through sensitive circuitry. This can be complex if the product is double insulated or uses no earth arrangement but is in a system with multiple other earth paths to ground i.e. via coaxial shields to other equipment.

Spark Gap/Gas Discharge Tubes (GDT)

Gas discharge tubes and other spark gap devices act as transient suppression devices by conducting electrical currents to ground, effectively creating a short circuit. In the case of a high-voltage spike, the normally non-conductive gasses (or air in the case of a simple spark gap with exposed electrodes) become ionized allowing for electrical current to be conducted through the gap between the terminals of the device.

GDTs take a relatively long time to trigger compared to other transient voltage suppressors. It is not uncommon for a GDT or sparks gap to allow pulses of 500V or more to pass through unsuppressed before the current is conducted to ground via the ionized gas/air between electrodes. Gas Discharge Tubes are more commonly used in slower rise time surge transients such as an AC mains surge.

Suppression/Filtering

ESD events can be mitigated using transients suppression components and/or filter networks. Transient suppression components include, but are not limited to Transient voltage suppression (TVS) diodes, capacitors, variable resistors/voltage-dependent resistors (varistors/VDR) and filter networks.

These components work by reacting to sudden over-voltage conditions and should be placed as close as possible to the point of ESD current entry rather than the circuit (or part of the circuit) that is being protected.

Galvanic Isolation

Galvanic isolation is the separation of electrical circuits that allow for signals to pass through but stray currents are eliminated. Common methods of achieving galvanic isolation include but are not limited to Transformers (coupled inductively/magnetically), optoisolators (coupled photo-electrically), capacitors (blocks DC but allows AC to pass) and hall-effect sensors (coupled inductively/magnetically).

Firmware

In some cases, a change in the firmware of a device is sufficient enough to allow it to self-recover after an ESD event. Where a device’s processor crashes (due to an ESD event) a watchdog timer (WDT) will reset the processor.

This can essentially bring it back to an original state making the malfunction in operation self-recoverable. In other cases, the firmware may help stop the device from malfunctioning.

A parasitic reset (when the reset pin of the processor erroneously reads high due to the ESD event) or blocked status can be managed by the firmware. Often this kind of solution is used in conjunction with filters which differentiate valid signals from short ESD events.

When designing a circuit it is important to keep these different techniques in mind. Different kinds of devices and circuit layouts will benefit from different techniques and often there is more than one solution to the problem.

More than often, multiple electrostatic mitigation techniques will be required in order to achieve EMC compliance during electrostatic discharge testing.

 

Source: Courtesy of EMC Bayswater Melbourne, Australia

 

What is Electromagnetic Compatibility Testing?

EMC Testing Service | EMC Bayswater

Electromagnetic Compatibility Testing Requirements

 

What is electromagnetic compatibility testing? Let us try and explain it! Most of the today’s electrical products and electronic equipment are subjected to electromagnetic compatibility testing.

Electromagnetic compatibility testing is commonly known as EMC testing. In Australia, this testing is compulsory for manufacturers of certain products. This testing is necessary to demonstrate that their products are compliant with EMC standards. And is essential to meet the mandated requirements for distribution to the market.

How is Electromagnetic Compatibility Testing performed

EMC Testing | EMC Bayswater

EMC testing should be conducted by an accredited testing facility. This EMC testing laboratory should be equipped with suitably calibrated EMC test equipment and facilities. Including the appropriate calibrated EMC test chambers.

The technical capability and resources to perform the test to the applicable EMC product standard.

The testing body can be a third-party testing facility or an in-house laboratory. It ideally would be an accredited testing facility. Usually accredited by the local testing accreditation authority for the region, ideally recognised in other countries.

In Australia, EMC testing facilities are usually accredited by the local Australian authority, which is the National Association of Testing Authorities (NATA). NATA accreditation is recognised by many other countries globally. This is usually through Mutual Recognition Agreements (MRA).

NATA is part of the International Laboratory Accreditation Cooperation (ILAC). ILAC  promotes the acceptance of test and calibration data around the world.

Importance of EMC Testing

Electromagnetic Compatibility Testing or EMC testing is mandatory for almost all products which have an electronic or electrical circuitry whether wired or wireless powered. This is to ensure that products can function satisfactorily in the environment which they are going to be used. Furthermore, so they do not cause interference to other products.

There is a huge benefit for manufacturers in testing their products. Especially during the entire development cycle. Associated delays and costly recalls of the products can be avoided. The earlier the products can be tested for EMC compliance during the development cycle the better. A failure in the test at the end of product development cycle can be extremely costly especially in the redesigning of the product.

What types and markets require EMC Testing

Compliance with the EMC testing is mandatory in almost all markets including the U.S., Europe and Australia, among many others. This test is required for manufacturers in various industries including:

  • Medical devices;
  • Consumer products;
  • Military equipment;
  • Industrial machinery;
  • Automotive;
  • Aerospace; and
  • Railway

To be able to avoid delays in the marketing of your products, you need to properly prepare for what is needed prior to the final EMC testing. You must also allocate enough time to book an available booking at the testing laboratory, sometimes the lead time can be weeks.

You must also allow a contingency plan if the product initially does not comply. Allow time for any re-work or modifications are required i.e. compliance engineering the product to meet the standards.

Preparation for EMC Testing

It’s imperative for manufacturers to prepare the EMC testing requirements prior to entering the EMC test chamber in order to achieve the best results. Here is a helpful guide in preparing for EMC testing.

Write a test plan

Before the testing is done, it is necessary to be able to define the process beforehand. Analysing the requirements and knowing the types of test that your product needs to undergo is imperative. You need to know whether your product is subjected to conducted and radiated emissions only. Or if you will also need the EMC immunity testing as well.

You will also need to know which ports will be tested, which levels or limits will be used and what the pass and fail criteria are. That is why writing a test plan is essential.

How to write a test plan? EMC Test plan template

If you have already undergone Electromagnetic Compatibility Testing before, then you will be able to create a test plan yourself. However, if it is your first time to have an EMC test conducted, you can contact your test lab and seek a professional EMC test plan to be prepared for your particular product. A good test plan must have the following:

  • Product name, model number and identification details;
  • Product description of device to be tested including its I/O configurations and peripherals;
  • Required standards and applicable tests that are listed in the standards;
  • Quantity of samples requiring testing;
  • Product power supply requirements, i.e. 115/230VAC, 50/60Hz, 12VDC, PoE etc;
  • Dimensions of the product/system and also the weight of the product/system;
  • Type of equipment is it table top or floor standing;
  • Transmitter information if a wireless radio module is incorporated or used;
  • The lowest and highest internal frequencies used within the product;
  • Ports table including cable types, quantities, terminations and cable lengths;
  • Operating modes of the product;
  • Operating mode of the product and configuration for emissions testing (worst case);
  • Product emissions limits i.e. Class A, Class B etc (if applicable);
  • Operating mode of the product and configuration for immunity testing (worst case);
  • Declaring the intended environment, such as Basic, Industrial or Controlled EM etc;
  • EUT cycle time to complete all operations and allow observation of any failures;
  • Customer specified performance criteria and ways to recognise monitor and report failures;
  • Test fixtures, special software and supporting equipment to correctly exercise the product;
  • Definition of failure;
  • Estimated set-up time of the physical configuration and support equipment/software;
  • Declaring any health and safety related issues such as hazardous materials etc;
  • Special needs such as power, software and cooling among others;

Getting the price and schedule

Once you have the test plan written, you can now get the pricing and scheduling from an accredited 3rd party EMC test lab such as EMC Bayswater. Prepare the software and hardware for testing. You need to inquire what the lab will supply. More often than not, you will need the following:

  • Equipment under test (EUT) and spares;
  • Test fixture (if required);
  • Connectors and cables;
  • EMI suppression supplies such as ferrites, copper tape;
  • Tool kit;
  • Equipment’s design

During the test, you will need a compliance engineer or someone who is familiar with the product to witness the testing process.

Preliminary testing or pre-compliance testing

Preliminary testing or pre-compliance testing is also necessary to avoid possible failures in the final testing. There are shortened versions of the various test methods that can be done to identify possible failures.

Before the final testing, design modifications can be made. The most common pre-test that can be done is the radiated emissions pre-test. This pre-scan determines failures and suggests possible design modifications to enhance the equipment so it performs better for other test methods when needed.

Preparation prior to testing

Additionally, possible delays can be avoided if you are well prepared before the testing. Hence, when preparing your software and hardware for testing, you need to take note of the following:

  • The product that has to be tested must have its peripheral equipment included which constitute the entire system;
  • Any optional or auxiliary equipment that may be required during the test. If your product has a USB port, include a USB peripheral that can be used for that port. If you don’t ship a product with USB peripheral, then you provide a typical unit. Ensure that unit is pre-compliant to avoid failure during the test;
  • If functional auxiliary equipment for a particular port is not possible, dummy loads that exercise a port to its fullest extent will often do;
  • A monitoring method. This is crucial for immunity testing since the lab needs to monitor the performance of your product. Clearly defining methods for which you would like your product to be monitored is helpful to EMC test labs;
  • Two or more alternative backup power supply units. This is helpful whenever there’s a failure in conducted emissions testing. Conducted emissions problems can often be alleviated by swapping an external power adapter with a better performing one. Having more adapters can also be useful when doing surge testing;
  • Cables that are needed when exercising your product to the fullest. They must be the right length.
  • A software/firmware test mode that is needed when exercising all communication interfaces, memory interfaces and all moving parts at the highest speed possible; and
  • Proper documentation needed by the test engineers. This is highly important because if test engineers don’t know how to set up or operate your product into the proper test mode, it could delay in the test schedule.

Source: Courtesy of EMC Bayswater Melbourne, Australia

Why Small Businesses Must Invest in Robots

small businesses invest in robots

Robotics is delivering a host of benefits to small businesses and the rest of the global economy.

No wonder more and more businesses turn to robotics to streamline operations. With this trend expected to continue, have you ever wondered what the workplace of the future would look like?

Some analyses infer that a huge percentage of the current employees will be taken over by robots. Hence, the use of robots is expected to increase.

On the other hand, the recent move by Mercedes to replace some of its production robots with people to keep up with the growing demand for more customization options indicates that people and robots can and will continue to work together.

Either way, robots undoubtedly benefits businesses and they are here to stay. Thus, it’s time to look at how they can work for you.

Here are the reasons small businesses must invest in robots and the potential advantage of making such a move.

Robots are more affordable than ever

Gone are the days when a single robot would cost at least $100,000. This is way above what most small businesses can afford without hurting their bottom line.

Today’s evolutionary robots, according to Barclays, cost an average of $24,000 each. There are even small robots which don’t cost more than $10,000.

This price tag can also be considered reasonable as a single contemporary robot can perform various tasks.

It’s easier to use robots today

You’d only need to use a tablet to program your robot or move its arm in the required pattern. Thus you don’t need to hire a qualified programming engineer.

Robots have become much safer to work with

robots for small businesses

Today’s robots don’t work in cages. The collaborative robots can work with people in the same environment, thanks to the advanced sensor and vision technology. Thus, if you are on its way, you won’t get hurt because the robot will stop moving.

Robots are versatile today

You’ll find them in homes as vacuum cleaners or laundry robots, or in offices and industrial environments completing some of the risky or monotonous tasks.

These Universal Robots are now smaller and can adapt to various environments. They also come in different shapes and sizes depending on the kind of task it is expected to do.

This means they can help automate most of your production activities.   

Robots can significantly boost productivity

For the most part, robots are used for mundane or repetitive tasks. These are perfect for them since they will not feel bored or tired.

Moreover, robots will work the same way and at the same pace, hence, it will have the same production momentum throughout.

By automating the most repetitive and mundane parts of your company’s production processes, you can free skilled employees to focus their energy on more important tasks.

If a robot is filing papers, responding to general inquiries or taking calls throughout the day, for instance, business managers and other key workers have the freedom to focus on product development and other such key business processes, social and/or emotional component of the product or service.

Say goodbye to errors

Humans can commit costly errors, robots cannot. These machines are simply not affected by ambiguity. They can follow the standards you set and have no room for errors.

In contrast.  human workers could miss some important details or make mistakes because of burnout or fatigue.

Robots can help you control labour costs

Most companies are struggling with labour costs. It is worse in cases where there is high staff turnover. Recruitment cost and the cost of training new staff can cumulatively take a toll on your bottom line.

This cost is cut significantly when you automate. because you trim the number of workers you need.

What if a company can keep its labour costs at an all-time low while simultaneously increasing productivity? That’s a double blessing. And investing in today’s robots makes it all possible.

Wrap up

Robotics and related technologies already permeate the modern workplace and homes in a huge variety of forms.

This is so because business has realised the value these machines give — lower recruitment cost, lack of salary requirement, low maintenance cost and constant productivity, among others.  

In view of this, it’s time to reap these benefits by looking into areas where robots can work together with people and help your business thrive.