Major markets around the world have some form of ElectroMagnetic Compatibility (EMC) regulations in place to:

  1.  Safeguard critical communications of emergency services (e.g. police, medical services, fire departments, search and rescue), essential services (e.g. air traffic control, maritime communications, rail systems, vehicular traffic control) and military operations from ElectroMagnetic Interference (EMI).
  2.  Minimise interference between electrical and/or electronic equipment which could lead to safety issues depending on the function of the equipment (e.g. life support equipment, aircraft navigational equipment, vehicle electronic systems).

 Consequences of the above could be life threatening with the resulting harsh penalties which accompany loss of life.  Even if no severe consequences present themselves, any equipment that is affected by EMI could be annoying to the user and be interpreted by the user as poor reliability which would reflect badly on the brand and company.

 As such, in addition to simply complying with regulatory requirements, prudent manufacturers will design EMC into their product, which is to minimise emissions coming from the product, while at the same time ensuring that it has some level of immunity from EMI.

 In Australia, the Australian Communication and Media Authority (ACMA) is the regulatory body for EMC.  It carries out its EMC charter through the legal instruments of the Radiocommunications (Electromagnetic Compatibility) Standard 2008 and the Radiocommunications Labelling (Electromagnetic Compatibility) Notice 2008.  The Standard specifies the technical standards that apply to particular products, and the Labelling Notice spells out the compliance, labelling and document-keeping requirements.  In addition to EMC, the ACMA is also the regulating body for Radiocommunications and Telecommunications.

 Under the Australian EMC Regulatory Arrangement only limits for EMI emissions of a product is mandated.  Immunity requirements are not mandated although it is encouraged to improve product reliability and allow access to the European market where product immunity is a requirement.

 Only compliant products bearing the C-Tick mark (for non-Telecommunication products) or the A-Tick mark (for Telecommunication products) with the Supplier Code Number (SCN) can be imported and sold in Australia.

with “N# Supplier Code

Types of Mining Equipment

In the mining industry, a wide range of different equipment can be found, such as air-conditioning equipment, hand tools, alarm systems, controllers, computing devices, communication devices, motors, lights, laboratory and scientific equipment, surveying equipment, machine shop equipment to name a few.

Applicable EMC Standards

 There are a number of EMI standards to cover the plethora of equipment, with the more common standards being:

  Standard Equipment Type
1. AS/NZS CISPR 11 Industrial, Scientific and Medical (ISM) equipment
2. AS/NZS CISPR 14.1 Household appliances, electric tools and similar apparatus
3. AS/NZS CISPR 15 Electrical lighting and similar equipment
4. AS/NZS CISPR 22 Information Technology Equipment (ITE)
5. IEC 61326-1 Electrical equipment for measurement, control and laboratory use
6. AS/NZS 61000.6.3 Generic emission standard for residential, commercial and light-industrial environments
7. AS/NZS 61000.6.4 Generic emission standard for industrial environments

 

 Types of EMI Tests

When it comes to testing of products, it should be borne in mind that the following does have an impact on testing time and hence cost:

  1.  Highest clock/operating frequency within the product.  This will be of significance when ACMA requires AS/NZS CISPR 22 radiated emission testing above 1GHz in the near future.
  2.  Number of operating modes and/or possible configurations.  Any EMI testing will have to done in the worst-case emission operating mode and/or configuration.  It goes without saying that some time will need to be spent on investigating the emissions from the different operating modes and/or configurations for products with two or more operating modes and/or configurations. 

For all EMI emission tests, the tests are objective tests in the sense that the measured EMI levels are compared against relevant limits, and compliance is demonstrated when the levels are below these limits.

The various test methods are summarised below to give an idea of the different EMI tests that a product may be subjected to (depending on the applicable standard applied).

 Conducted EMI Tests (Mains Port)

This test measures the EMI generated by equipment and transmitted via the mains supply cable, which may affect other equipment connected to the same mains supply ring.  The test frequency range is generally from 9kHz to 30MHz or 150kHz to 30MHz depending on the applicable standard.  A typical setup for an ITE is shown below in Figure 3:

Figure 3 – Conducted EMI Test Setup

Measurements are made using a CISPR 16-1 defined, 50Ω/50µH Artificial Mains V-Network (AMN), or Line Impedance Stabilisation Network (LISN) as it is also known as, through which the mains supply is connected to the Equipment Under Test (EUT), while at the same time providing a measurement port connected to an EMI Receiver.

 Conducted EMI Test (Telecommunication Port)

 The setup of this test is similar to that for Conducted EMI Test on the mains port as shown in Figure 3 above, but in this case it measures the EMI transmitted via the telecommunication cable, which may affect other equipment connected to the same telecommunication network.  This test is only required by the ITE specific standard AS/NZS CISPR 22 and covers the frequency range from 150kHz to 30MHz.

 In this context, telecommunication port is defined as, “Ports which are intended to be connected to telecommunication networks (e.g. public switched telecommunication networks, integrated services digital networks), local area networks (e.g. Ethernet, Token Ring) and similar networks.”  USB and RS232 ports would not be considered as telecommunication ports.

 The measurement port is taken from the Impedance Stabilization Network (ISN) instead of the AMN.

 Discontinuous Interference Test

 Discontinuous interference is generated by switching operations within equipment using thermostatic controls, automatic controls and the like.  The setup is again similar to the Conducted EMI Test on the mains port, but the measured parameters are different.  As the name infers, in this case the measurement is on interference that are not continuous in nature, but transitory interference, also known as “clicks”.  A “click” is defined as, “a disturbance, the amplitude of which exceeds the quasi-peak limit of continuous disturbance, the duration of which is not longer than 200ms and which is separated from a subsequent disturbance by at least 200ms.”

This excludes individual switching operations used for:

  1. Mains connection and disconnection only.
  2. Programme selection only.
  3. Control of energy or speed within a limited number of fixed positions.
  4. Changing of the manual setting of continuously adjustable controls.

 Disturbance Power Test

This test is essentially to measure radiated EMI emissions coming off cables, and generally applied to equipment where EMI emissions are more likely to be radiating from the cables than from the enclosure itself – such as electric tools, regulating controls using semiconductor devices, motor-driven electro-medical apparatus and the like.  The test focuses on the cables connected to the equipment, and requires the cables under test to be extended to at least 6m in length.  A typical test setup is shown in Figure 4 below:

Figure 4 – Disturbance Power Test Setup

Due to the mismatches that occur between the EUT and the connection at the other end of the cable, standing waves are created which cause the EMI emission level to “peak” and “valley” along the length of the cable.  The Absorbing Clamp is moved along the 6m length of cable to measure the highest “peak” EMI emission level coming off the cable for every significant emission frequency relative to the limit within the test frequency range of 30MHz to 300MHz.

Radiated EMI Test (Loop Antenna)

Radiated EMI emissions from electrical lighting and similar equipment are measured within a Loop Antenna in its three orthogonal axes.  The Loop Antennas come in various sizes (2m, 3m or 4m) to accommodate different sized lighting equipment.

Figure 5 shows a typical setup for the Loop Antenna test.  The radiated EMI emissions are measured within the test frequency range of 9kHz to 30MHz.

Figure 5 shows a typical setup for the Loop Antenna test.  The radiated EMI emissions are measured within the test frequency range of 9kHz to 30MHz.

 Radiated EMI Test (OATS)

This test is performed at one of Austests’ Open Area Test Sites (OATS) to measure the radiated EMI emissions emanating from the enclosure of the EUT.  It is generally used for measurement of digital EUTs where clock/operating frequencies within the EUT can cause emissions well up to the hundreds of MHz, and possibly even into the GHz region with technological advances of greater processing power and speeds.  It is for this reason that the current test frequency range, from 30MHz to 1GHz, will include testing up to 6GHz for ITE in the near future (depending on the highest digital frequencies generated within the EUT).  Figure 6 – Radiated EMI OATS

 

The OATS, as the name implies is an open area with a conductive ground plane on which measurements are made, at the normal test distances of either 3m or 10m between the EUT and the measurement antenna.  A typical test setup is shown below:

In order to maximise the EUT emissions at each significant emission frequency, the EUT is rotated through 360 degrees on a non-conductive turntable, with the antenna in one antenna polarisation, and then again in the other polarisation.  The antenna is then set to the highest emission polarisation (either horizontal or vertical), and the EUT is set to the direction to the antenna that gave the highest emission level.  The antenna, mounted on an antenna mast, is then scanned from 1m to 4m to determine the height at which the maximum emission level is obtained.  This maximum emission level is then measured at the EMI Receiver for comparison with the applicable limit.

The antenna height scan is necessary since the antenna picks up emissions that come directly from the EUT as well as emissions reflected off the ground place, which depending on the height of the antenna, may be in-phase or out-of-phase with the direct path emissions.  If the reflected emissions are in-phase, they add to the direct path emissions giving a worse-case level; and when the reflected emissions are out-of-phase, they subtract from the direct path emissions giving a lower emission level.

 

 So What Do I Do?

 

If you are an equipment purchaser or user, you should check that the equipment label has the A-Tick or C-Tick (depending on whether the equipment has telecommunication functionality or not), and has the necessary safety approval number as a minimum.  If there is no such labelling on the equipment, check with the equipment supplier on the Australian compliance of the equipment as it is illegal to sell non-compliant equipment in Australia.  If non-compliant equipment is identified, the respective regulators need to be informed (ACMA for A-Tick or C-Tick issues, and the State Safety Regulator for safety approval issues).

 

If you are an equipment manufacturer, importer or seller in Australia, you must ensure you comply with all Australian requirements as there can be severe regulatory penalties for non-compliance.  Apart from EMC, electrical products must comply with the essential requirements of AS/NZS 3820 which references product specific safety standards such as AS/NZS60950 for information technology equipment of AS/NZS3100 (General Requirements for Electrical Equipment).  Energy Efficiency requirements may also apply to your product.

 

As the regulatory requirements can appear daunting, it’s best to engage a company versed in EMC and Safety to advise on Australian compliance requirements for a particular equipment.  This is even more so as the range of mining equipment is so varied.  Test labs provide a range of services from testing of products to assessing overseas reports for compliance with Australian requirements.  Test labs are mindful of the cost of testing to the manufacturer, importer or supplier, and if some valid testing has been done overseas, these reports may be used in combination with limited additional testing to cover Australian deviations/specific requirements.   

 

If you’re located in Australia, refer to Austest Laboratories

For New Zealand contact Harvest Laboratories

For Global Approvals and certification Contact Approval Specialists