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German ESD network - KARL is part of it!
EVERYTHING ABOUT ESD
THE GERMAN ESD NETWORK
Everything from a single source and the best expertise in the field of ESD protection and prevention of ESD damage - that's what the German ESD networkconsisting of the four companies KARL, KEINATH, nora and Wanzl.
From planning a new EPA (Electrostatic Protected Area), to selecting the right ESD flooring, to access controls, to workstations and the necessary equipment and tools, the four companies offer the hardware as well as the expertise to make your production ESD-safe.
In addition, the ESD network offers audits (certification of EPAs), training programmes, inspections of ESD protection zones as well as seminars and training courses for your employees.
To prevent damage to electrostatically sensitive components, the German ESD network has published a compact ESD guide. On 32 pages, it explains the formation of electrostatic charges, the resulting potential hazards, how to avoid them and how to set up an EPA (Electrostatic Protected Area), as well as listing the currently applicable standards and terminology.
Short, concise, easy to understand and attractively presented, we would like to provide you with this guide free of charge as a company-internal source of information for your employees. Interested? Then use the download for our ESD guide. We would also be happy to send you a paper copy.
ESD RULES OF BEHAVIOUR
Whether employees, visitors or business executives: In the case of electrostatically sensitive components, each individual within an ESD protection zone must adhere to the rules. This is the only way to effectively prevent damage and guarantee the function and reliability of your own products.
- Employees must be convinced of the necessity and effectiveness of ESD protection measures. This requires targeted training with competent and convincing instructors!
- Every employee in an electronics production facility must be familiar with the relationships between the generation and effects of electrostatic charge.
- ESD protective measures apply to all persons entering the EPA. Therefore, short-term employees, supervisors and visitors must also be equipped with ESD protection.
- ESD protective measures apply to every stage of production. They are defined by the ESD officer and apply without restriction.
- The effectiveness of the personal earthing measures must be checked daily before entering the EPA and this must be documented.
- Defective or missing ESD protection measures on equipment and machines as well as potential sources of danger must be repaired or reported immediately.
- ESD personal protective equipment may only be worn and handled in the prescribed manner. This is the only way to ensure that charges are prevented and dissipated accordingly.
- Conductive floors and ESD-suitable surfaces may only be treated with the prescribed cleaning and care products. Otherwise their conductivity may be impaired.
- Only ESD-suitable containers and packaging materials may be used within the EPA. Unsuitable packaging materials must remain outside the ESD area.
- Important handling rules must be observed when processing ESD-sensitive components and assemblies.
Hazardous components and assemblies must never be placed on metallic surfaces, as there is a risk of a hard discharge. Similarly, insulating trays or chargeable materials must not be used.
WHY ESD PROTECTION?
We encounter electrostatic discharge on a daily basis: the "knock" you get on the car door, hair sticking out when you take off your hat or when there is a "spark" between two people.
What is a brief scare for us and usually just a nuisance is quickly a total loss for electronic assemblies that are fitted with small and tiny semiconductor components. Discharges with a potential of 10,000 volts are not uncommon, especially in dry air.
Avoiding ESD is therefore one of the top priorities for companies in the electronics industry.
In the worst-case scenario, a lot of damage caused by ESD is only discovered by the customer after some time and then leads to high repair or replacement costs. Much worse than the financial damage is the subsequent damage to the company's image if an entire product batch has been affected by a protracted fault.
TERMS AND STANDARDS
Leakage resistance. The leakage resistance is the resistance between an electrode on the top of a device and the ESD earthing point. The earth leakage resistance is the resistance between an electrode on the top of a device and the earth potential.
Discharge time. The time interval in which a charged body is discharged from an initial value to a final value, e.g. from 1000 V to 100 V, through the connection to earth potential.
CDM. The Charged Device Model describes the mechanisms that occur when a charged component is discharged.
The electrostatic sensitivity is determined by a pulse defined via the equivalent circuit.
Conductive(conductive). These are materials that are either surface conductive, volume conductive or both. Their surface resistance or volume resistance must be less than 104 ohms (according to DIN EN 61340-5-3).
Dissipative(dissipative). These are materials that are either surface conductive, volume conductive or both. Their surface resistance or volume resistance must be ≥ 104 Ohm and < 1011 Ohm (according to DIN EN 61340-5-3).
EBP. Earth Bonding Point is the labelled connection for all ESD earthing measures; must not be used as a protective earth conductor.
EPO. The Electrostatic Protected Area is an area equipped with ESD protection measures in which ESDS can be manufactured, processed, packaged, transported or stored without the risk of electrostatic damage.
ESD. Electrostatic Discharge, is the electrostatic discharge as potential equalisation between charged bodies through direct contact or flashover.
ESD models. Idealised models are used in an attempt to simulate real ESD discharges and define test methods for determining component sensitivity. The most important models are HBM, CDM and MM.
ESDS. Electrostatic Discharge Sensitive Device. Designation for components or assemblies that can be damaged by electrostatic discharge during handling, processing or transport.
ESD voltage sensitivity. Damage limit of a component to certain discharge pulses of the discharge models HBM, CDM or MM.
Electrostatic charge. In physics, this is understood to mean static electrical charges that are created by mechanical contact and subsequent separation of materials.
HBM. The Human Body Model describes the mechanisms that occur when a charged human body is discharged via a component or assembly. A pulse defined via the equivalent circuit causes the electrostatic discharge of the human body.
Sensitivity determined.
Ionisation.Positive and negative ions generated by the corona effect under high voltage neutralise electrostatic charges. Mainly used for discharging non-conductors.
IsoIator. Materials are insulating if the surface resistance is greater than 1011 ohms.
Insulating. Are materials that are either surface insulating, volume insulating or both, whose surface insulation or volume insulation is ≥ 1011 Ohm.
Low charging. Materials are weakly chargeable if they have the property of not becoming charged or only becoming insignificantly charged on contact and subsequent separation or friction.
MM.The machine model describes the mechanisms that occur when a charged machine or system component discharges. The electrostatic sensitivity is determined using a pulse defined via the equivalent circuit.
Surface resistance. The surface resistance of a material is the electrical resistance between two electrodes placed on the surface. For comparative measurements, the distance between the electrodes must be specified.
Potential equalisation. Any electrostatic charges that arise must be equalised immediately against earth potential (0V) without risk of ESDS. The primary objective of ESD protection is to prevent the build-up of static charges.
Volume resistance. If a material is made entirely of conductive material, the current essentially flows through the body of the material. The resistance is measured between an electrode on the upper side and a counter electrode on the opposite side on the underside of the material.
Volume conductivity.Characterised by the fact that the entire material is dissipative, not just the surface.
STANDARDS
DIN EN 61340-5-1. Electrostatics - Part 5-1: Protection of electronic components against electrostatic phenomena - General requirements.
DIN EN 61340-5-2. Electrostatics - Part 5-2: Protection of electronic components against electrostatic phenomena - User's guide.
DIN EN 61340-5-3. Electrostatics - Part 5-3: Protection of electronic components against electrostatic phenomena - Characteristics and requirements for the classification of packaging used for components sensitive to electrostatic discharge.
DIN IEC/TR 61340-5-5. Electrostatics - Part 5-5: Protection of electronic components against electrostatic phenomena - Packaging systems for use in electronics manufacturing.
DIN EN 61340-4-1. Electrostatics Part - 4-1: Standard test methods for special applications (electrical resistance of floor coverings and installed flooring).
DIN EN 61340-4-2. Standard test methods for special applications - Methods for determining the electrostatic properties of textiles.
DIN EN 61340-4-3. Electrostatics - Part 4-3: Standard test methods for special applications (footwear).
DIN EN 61340-4-4. Standard test methods for special applications - Classification of flexible bulk containers in electrostatic terms.
DIN EN 61340-4-5. Electrostatics - Part 4-5: Standard test methods for special applications (Methods for characterising the electrostatic protective effect of footwear and floor in combination with a person).
DIN EN 61340-4-6. Standard test methods for special applications - HGB.
DIN EN 61340-4-7. Standard test method for special applications - ionisation.
DIN EN 61340-4-8. Standard test methods for special applications - Shielding effects against electrostatic discharge - Bags.
DIN EN 61340-4-9. Standard test methods for special applications - Clothing.
DIN EN 61340-3-1. Electrostatics - Part 3-1: Methods for the simulation of electrostatic effects - Test pulse shapes of electrostatic discharge for the Human Body Model (HBM).
DIN EN 61340-3-2. Electrostatics - Part 3-2: Methods for the simulation of electrostatic effects. Test pulse shapes of the electrostatic discharge for the Machine Model (MM).
DIN EN 61340-2-1. Electrostatics - Part 2-1: Measurement methods. Ability of materials and products to dissipate electrostatic charges.
DIN EN 61340-2-3. Electrostatics - Part 2-3: Test methods for the determination of the resistance and resistivity of solid planar materials used to prevent electrostatic charging.
DIN IEC/TR 61340-1. Electrostatics - Part 1: Electrostatic processes - Basics and measurements
ANSI/ESD S20.20. ESD Association Standard for the Development of an Electrostatic Discharge Control Programme. Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiated Exposive Devices).
HOW ARE CHARGES CREATED?
To electrostatically charge a solid, charges must be separated. To do this, the two materials are first brought into contact and then separated from each other. Contact refers to the molecular distance between the material surfaces so that electrons can be transferred from one material to the other.
When two materials with different electron work function come into contact (e.g. plastic shoe sole and textile floor covering), electrons flow from the material with the lower work function into the material with the higher work function. As a result, one body becomes negatively charged and the other positively charged. This results in a potential difference ranging from a few mV to a few volts.
Their permittivity (dielectric conductivity) is decisive for the polarity that the materials assume. Depending on the material pairing, one material is charged positively and the other negatively.
If the two materials are now separated again, the charges can remain. This depends on the separation speed, specific material properties and humidity. The time constant τ =R-C is determined by the surface resistance and the charge capacity.
Whether in the human body or in assembly machines - contact and separation occur in every workplace. This is why ESD protection is essential in the electronics industry.
WHEN DO LOADS BECOME DANGEROUS?
If the objects that come into contact with each other are made of highly conductive materials, there is a high probability that a charge equalisation will occur while the two objects are still separated. This is due to low resistance and good conductivity. As a result, the time constant for the charge exchange is smaller than the time required for the separation equalisation.
However, if the materials are poorly conductive or even insulating and other factors such as low humidity play a role, the conductivity of the materials is severely restricted and the time constant for charge equalisation is reduced. larger than the separation speed.
As a result, both objects retain their previously assumed charge states.
If the last contact is then interrupted and the two bodies move away from each other, the potential difference increases. This is comparable to the way a capacitor works, where the voltage also increases significantly due to the increase in the charge surface distance.
If there was a contact voltage of a few mV when the objects were brought together, this is drastically increased to up to several kV by increasing the distance to more than one millimetre. The maximum charging voltage is limited by the surface charge density.
Reduction in charge generation due to increased humidity
| Activity | Humidity 10% | Humidity >60% |
| Movement in the workplace | 6000 Volt | 100 Volt |
| Wrap paper in plastic wrapping | 7000 Volt | 600 Volt |
| Walking over plastic flooring | 12 000 Volt | 250 Volt |
| Remove bubble wrap | 26 000 Volt | 1000 Volt |
| Walking over carpet | 35 000 volts | 1500 Volt |
DISCHARGE AND VULNERABLE ASSEMBLIES
Ever since semiconductor components triggered a technical revolution in electrical engineering in the 1960s, the problem of ESD protection has been omnipresent.
Components with conductor structures of less than 0.25 μm and reduced oxide thicknesses of well under 100 angstroms are becoming ever smaller and more powerful. However, this also makes them correspondingly vulnerable if an electrostatic discharge occurs.
The consequences are frequent:
- Thermal breakdown of a p/n junction
- Oxide breakdown (dielectric breakdown)
- Melting of the metallisation
To classify these more precisely, the standard refers to three models:
- HBM - Human Body Model
- CDM - Ccharged Device Model
- MM - Machine Model
Other models are described in the literature:
- SDM - Socket Device Model (model that simulates the discharge of an electrostatically charged component with associated base)
- CBM - Ccharged Board Model (Describes the discharge of an assembled module, through higher capacitances and inductances than in the Charged Device model)
- CSM - Ccharged Strip Model (In this model, the failures are simulated in matrix and strip form, for example in automatic placement machines)
- ESDFOS - ESD From Outside to Surface (Describes the direct discharge into the surface of the component structure; this occurs during the production of wafers and ICs)
SENSITIVITY OF SEMICONDUCTORS
| Semiconductor type | Electrostatic voltage (V) / |
| V-MOS | 30 ... 1800 |
| MOSFET | 100 ... 200 |
| EPROM | 100 ... 500 |
| Junction-Fet | 140 ... 1600 |
| Operational amplifier (Fet) | 150 ... 500 |
| Operational amplifier (bipolar) | 190 ... 2500 |
| CMOS | 250 ... 2000 |
| Schottky diodes | 300 ... 2500 |
| Film resistor | 300 ... 3000 |
| Schottky-TTL | 300 ... 2500 |
| Transistor, bipolar | 380 ... 7000 |
| Thyristor | 680 ... 2500 |
MATERIALS AND SURFACE RESISTANCES
- 1| Materials thatConductive (conductive). They have a low resistance of 104 Ω and thus ensure that the charge flows away quickly. If such materials (metals, carbon and even the sweat layer of human skin) are earthed via a connection, the entire charge flows away. For materials < 104 Ω, however, the risk of hard discharge must be taken into account.
- 2| Materials thatdissipative (dissipative) dissipate charges over a longer period of time. Their surface resistance is between 104 and 1011 Ω. This prevents ESDS from discharging too quickly due to contact with conductive surfaces. They are mostly used as packaging materials in the electronics industry.
- 3| Materials with a surface resistance of more than 1011 Ω have an effect insulating. They cannot dissipate existing charges and are electrostatically chargeable. This is a particular problem in the electronics industry, as they form charge islands that pose a danger to unprotected assemblies and must be avoided. Insulators include air, glass and plastics.
- Materials thatshielding act like a Faraday cage. This means that assemblies encased in such a material are protected from the effects of electric fields. They are fitted with a conductive metal or carbon element that has a surface resistance of less than 10³ Ω.
PROTECTION AGAINST ELECTROSTATIC DISCHARGE
THE ESD PROTECTION CONCEPT
1.
Protective circuits are integrated into all input and output paths to protect the sensitive components of devices from internal damage caused by discharges in the conductor network. These react to short-term discharges, ground them and thus protect the components behind them from damage.
2ND | PREVENTION
Where no charges occur, no discharges can damage components. This is why employees' clothing, tools, equipment and floors in Electrostatic Protected Areas (EPA) are ESD-safe. Ionisers are also used to neutralise charges and humidifiers to reduce the tendency to charge.
3. LABELLING
Knowledge transfer and warnings are essential when handling ESD-sensitive components. EPAs and components must be easily recognisable for non-ESD-protected visitors and suppliers or completely blocked off. It is particularly important to sensitise employees to the topic. Training and further education are the be-all and end-all here.
PROTECTION STRATEGY
| INCOMING MATERIALS, INTERMEDIATE STORAGE
Semiconductor components can be damaged by non-ESD-protected packaging, storage containers and adhesive tapes as well as by unprotected handling by employees. Therefore, every employee in the ESD area must be convinced of the necessity and effectiveness of ESD protection measures and this must be ensured through annual training.
| WORKSTATION, MACHINE
It is essential to ensure that all equipment is capable of preventing the build-up of electrostatic charges and dissipating charges in a defined manner. All equipment, workstations and machines must be checked regularly and this must be documented.
| STORAGE AT THE WORKPLACE
ESD-sensitive components can be damaged by the influence of unsuitable packaging and materials.
Therefore, these components may only be handled and processed at ESD-protected workstations. It must be ensured that no electrostatic fields are present at the workplace.
| DELIVERY AND PACKAGING
When packaging, always ensure that an ESD notice is clearly visible. Care must also be taken to ensure that ESDS outside an ESD protection zone are always stored and transported sealed in shielding packaging.
| TRANSPORT
During transport, care must be taken to ensure that ESD-suitable containers and transport trolleys are always used.
Even transparent sleeves for transport documents that are not made of ESD-safe material can cause damage. Intermediate storage on unsuitable materials should always be avoided.
INTERNAL PROTECTIVE MEASURES
To protect the tiny semiconductor elements from ESD damage and voltage peaks, on-chip protective structures are connected upstream and downstream.
Arrays of resistors, diodes, zener diodes, transistors and varistors are used here.
Unfortunately, there are also limits to this protective mechanism, which is why these internal measures are only of limited help. The reasons for this are
- Influencing the input sensitivity
- Change in the frequency spectrum or access time
- Use of equally sensitive components that are only slightly faster or less sensitive to ESD pulses than the input structure
- The circuits require additional space on the chip surface
The smallest structures inside modern chip components can be as small as 14 nm. A nanometre is one millionth of a millimetre.
EXTERNAL PROTECTIVE MEASURES
To create an area in which electrostatic charges cannot occur (Electrostatic Protected Area - EPO), many points relating to the workplace must be fulfilled.
From the right flooring system, markings and access barriers to work clothing and the actual workplace, there are numerous standards to fulfil.
| FLOORING
ESD floor coverings, e.g. dissipative ESD rubber flooring, are installed in production halls to ensure that any charges that occur are safely dissipated. These floors are dissipative and fulfil the required limit values from IEC 61340-5-1. Typical and good values are generally between 106 and 107Ω measured against EPA soil.
| MARKINGS
Markings on the floor are used to mark storage areas for transport trolleys or specially ESD-protected areas. Signs and stickers are equally important to indicate potentially hazardous components and assemblies.
| WORKPLACE
The perfect workstation should be ergonomically customisable and ESD-protected. The storage surface and an earthing cable dissipate electrostatic charges and keep the workstation charge-neutral.
| CLOTHING
Shoes, coat and wrist strap with earthing cable are mandatory for employees in the production of electronics companies. The protective measures for personal earthing must be checked daily for effectiveness before entering the EPA.
| PACKAGING
Slowly dissipating foam underlays are often used in production in particular. When assemblies are transported from A to B within the company, particular attention must be paid to good outer packaging that has a dissipative or even shielding effect
| PACKAGE
Whether for the transport or storage of components in the workplace - ESD containers protect vulnerable components and assemblies and are a must in the company. Unsuitable containers can generate strong charges and introduce them into an EPA, which affect ESDS through induction.
HUMIDITY AND IONISATION
Especially in winter, when the humidity is low (below 15 per cent), we often feel the effects of electrostatic discharge, and usually very clearly:
The crackling when you take off your jacket and the way your jumper is pulled close to your body afterwards, or the occasional knock you get when you get into the car.
| HUMIDITY
Humidity has a major influence on the discharge behaviour of materials. While the charging tendency of materials increases sharply in dry air, it decreases sharply in humid air. A fine film of moisture forms on the surface of the materials.
Therefore, no ESD measurement should be carried out at a humidity of more than 55 per cent, as this will lead to incorrect measurement results.
A constant humidity of between 40% and 60% can be a very effective additional ESD protection measure, but all process parameters must be taken into account when regulating it.
Various ionising systems are used in ESD areas:
Simple table-top models (top) for partial use, overhead models for ionising entire workstations or ionising bars with optional compressed air supply (bottom)
| IONISATION
If it is not possible or sensible to use dissipative material, charge reduction or discharge using an ioniser is an effective method.
Very often, assemblies are connected to highly chargeable housing parts during the assembly process. Ionisation is usually the only solution here. In this process, positive and negative ions are generated by means of high voltage through the corona effect. A stream of air transports these to the charged component and neutralises the charge present there. It should be noted that the effect of ionisers decreases significantly with distance.
During installation, the discharge time of the ioniser should be checked using a charge plate set (accessory for electric field meters for testing air ionisation units) in order to ensure sufficient discharge time for the respective process, and regular inspection of the ionisers is absolutely essential, as the high-voltage electrodes wear out and become dirty during operation, which greatly impairs their effectiveness.
Thanks to the targeted use of ionisers and the necessary ESD protection devices, there is no risk of damage when the component comes into contact with the circuit board.
ACCESS CONTROL WITH ESD PERSONAL CHECK
Even the best security guidelines are useless if compliance with them is not checked regularly.
Protective measures for personal earthing such as footwear or the wrist earthing strap must be checked daily before entering the EPO.
Access barriers at the entrances to EPAs are therefore a must. They measure the leakage resistance and only allow access once the test has been passed. This ensures that all persons entering the area are reliably earthed and that the main earthing measures in place are working.
In addition to the actual ESD protection, the manufacturer offers, for example wanzl access control systems customised to the customer. These are equipped with additional security-relevant functions such as panic protection, which releases access in an emergency by means of a counter-pressure specified by the TÜV without the need for testing.
To prevent unauthorised persons from using this option to gain access to the EPA unnoticed, this passageway is protected by acoustic and visual alarm signals.
It can also be connected to the building's fire alarm system. In an emergency, the access barriers open the passageway automatically, thus ensuring a barrier-free escape route for staff.
DISSIPATIVE ESD FLOORS
The use of a suitable ESD floor system is essential to ensure ESD protection.
Dissipative nora® flooring systems made of rubber offer this reliable protection - in several respects:
Avoidance of load:
Stresses that do not arise when walking are the best protection against ESD
(Walking test for nora® ESD floorings: < 10 V).
Discharge of charge:
The guaranteed electrostatic properties ensure permanent ESD protection for the production process. (resistance < 3.5 x 107Ω in the human footwear-floor system test according to DIN EN IEC 61340-4-5).
Protection of persons:
The minimum insulation in accordance with VDE 0100/600 also ensures personal protection. Homogeneous and volume-dissipating rubber floors safely and permanently dissipate voltages via the copper strips laid beneath them and are therefore the ideal basis for ESD-protected production.
Floor system consisting of nora® ESD flooring and nora dryfix™ ed dry adhesive
nora dryfix™ ed is an ESD dry adhesive on a roll for the installation of electrostatically dissipative (ed) and electrostatically conductive (ec) nora® floorcoverings.
Installation is simple and requires just a few steps - for more space in less time. This innovative solution reduces drying and waiting times, as the flooring can be used immediately after installation.
CLEANING AND CARE OF ESD FLOORS
Only use care products that do not build up layers so that the discharge values remain within the defined range.
Dissipative ESD rubber flooring systems can be cleaned and maintained on a daily basis using pads designed for this purpose. This maintains ESD protection, saves money and resources and protects the environment.
MEASUREMENT TECHNOLOGY
In order to avoid unnoticed damage to sensitive semiconductor parts and components, regular checks and inspections in an EPA are necessary.
Otherwise, there is imminent danger, as the components concerned may still function after damage and may even pass a functional test, but then fail after a fraction of the actual life expectancy at the customer's premises.
Due to this high hazard potential of the components used, only materials whose properties exclude electrostatic hazards to the components must be used in production.
As the discharges and equalising currents that occur are usually imperceptible to humans, it is necessary to check the protective devices regularly using measurement technology.
Resistance measurements of the materials and equipment used are of fundamental importance here.
This starts when entering an EPA with access control and personal checks of the employee, extends to the regular measurement of the ESD floor and naturally also includes the surfaces and work equipment at the workstations.
This is the only way to ensure that no damage is caused by ESD during production.
At Keinath's training centre, course participants are taught how to use the various measuring devices and the correct test set-ups in accordance with standards.
PERSONAL EARTHING
People generally generate electrostatic charges when walking or sitting, but also through clothing friction.
For this reason, various protective measures must be used to prevent charges and dissipate them in a targeted manner.
The two classic variants of ESD clothing are coats and shoes. Thanks to the interwoven conductive fibre grid, the coat serves to prevent people from charging and to shield the undergarments from charges.
The conductive contact surfaces of the shoes ensure that the wearer is earthed via the ESD floor covering and that harmful charges can flow away.
At seated workstations, the wrist earthing strap is used if the shoe-floor system cannot be secured. This discharges the electrostatic charge directly from the body via the EBP (Earth Bonding Point) located at the workstation and grounds the employee so that they are no longer at risk.
KETEX® ESD garments are the ideal solution for your EPA.
KETEX® combines unbeatable comfort with first-class properties.
KETEX® workwear can also be perfectly customised for your company using our finishing service.
ESD WORKSTATION
In order to fulfil ESD protection requirements in production, a workstation in an EPA must comply with the international standard IEC 61340-5-1. In the current internationally valid edition of this standard, only upper limits for the surface resistance and the leakage resistance of 1 x 109 Ω (dry measurement, 100 volts).
However, in order to safely avoid damage due to rapid, uncontrolled discharge according to the charge device model, the lower value of 104 Ω must not be undercut.
The ideal solution is a conductive overall system in which all add-on components (table structure, shelves, drawer, footrest, etc.) are conductively connected to the table frame via defined contact points.
An ESD-safe table top with a volume-conductive carrier plate is therefore particularly important. With a high-quality hard laminate covering, the mechanical resilience of the surface is also improved many times over and increases its service life.
TIPS FOR WEIGHT LOSS MEASUREMENT
GROUNDING
The earthing of the SINTRO workstation from KARL is ensured via three points: via the mains connection of the electrification (protective contact, PE), the central earthing point (EBP) on the table frame and via the conductive feet and the ESD floor (disadvantage: relatively undefined contact resistance, which can be reduced over time by dirt deposits).
and damp mopping).
PERSONAL EARTHING
Via wrist strap, which is connected to the earthing module with a safety resistor of one megohm and 10 mm push button. The wrist strap ensures that charges flow away and therefore no potential difference (i.e. electrical voltage) can occur.
