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2 Operational Safety User Manual HS -50 2.7 ESD guidelines Software Version SR.501.xx 12/99 Issue U S 90 t I I t 2.7 ESD guidelines 2.7.1 What does E SD mean? Almost a ll of the m odules in use to day are equipp ed with …
User Manual HS-50 2 Operational Safety
Software Version SR.501.xx 12/99 Issue US 2.6 Lock out and tag out procedure
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2.6.5 Training
(1)Employee training
The safety regulations require training for every individual, of course every employee is not ex-
posed to the same degree of danger or is involved with LO/TO as others are. So extensive
training is not necessary for everyone. 2
(2)To determine how much training to provide for each worker, the employees are divided into
three groups. Each group has its own level of training.
(3)Authorized employees
These workers actually install the locks and tags and do the maintenance or service work. So
they must know the most about controlled energy. First, they must be able to recognize all
energy sources and measure the amount of energy. Authorized employees must look for en-
ergy sources out of the realm of the obvious. These energy sources include electrical, mechan-
ical, hydraulic, pneumatic, chemical, thermal and gravitational. Once these workers can
recognize all energy sources they must be taught how to isolate, control, and release the en-
ergy without any risk. 2
(4)Affected employees
These are workers who operate the machinery or equipment that may be de-energized. Other
employees who may be affected include those who work in an area that contain equipment that
may be locked/tagged out. These employees have to be instructed about the nature of the en-
ergy control program, they must know why lock/tag out is important, what tags and locks look
like and why they must not remove tags or locks. 2
(5)All others
As the name implies, any employee who is not affected or authorized fits into this category.
There employees include office personal, engineers, managers, and upper management. Al-
though they do not have a direct relationship to the machinery being locked or tagged, they
have to receive some training. 2
(6)To evaluate the lock/tag out procedure, the safety department will conduct periodic inspec-
tions. As part of the inspection the safety department will document that all facets of the pro-
cedure are followed. The safety department will follow up with formal classroom review or re-
training of the LO/TO procedure.
2.6.6 Review
This procedure will be reviewed and amended as required but in no case less frequently than once
a year. 2
2 Operational Safety User Manual HS-50
2.7 ESD guidelines Software Version SR.501.xx 12/99 Issue US
90
t IIt
2.7 ESD guidelines
2.7.1 What does ESD mean?
Almost all of the modules in use today are equipped with highly integrated MOS blocks and com-
ponents. The manufacturing techniques used mean that these electronic components are ex-
tremely sensitive to overvoltage and thus to electrostatic discharge. 2
The abbreviation for such modules is ’ESD’ (Electrostatic Sensitive Device). This is used interna-
tionally, although the German abbreviation ’EGB’ may also be seen. 2
The following symbol on cabinet rating plates, racks or packaging indicates that components
which are sensitive to electrostatic discharge have been used and thus that the modules con-
cerned are also touch-sensitive. 2
ESDs can be destroyed by voltages and power levels that are far below the level
that can be perceived by humans. Such voltages occur if a person touches a com-
ponent or module without earthing themselves. Components that are exposed to
such overvolt-ages do not generally appear to be defective immediately - incorrect
behavior starts after the component or module has been in operation for some time. 2
2.7.2 Important measures to protect against static charging
Å Most plastics can easily become charged and must therefore be kept away from at-risk com-
ponents.
Å Always ensure that people, the workplace and packaging are safely earthed when handling
electrostatic sensitive components.
2.7.3 Handling ESD modules
Do not touch electronic modules unless it is absolutely essential to do so in order to carry out other
work. If it is necessary, make sure that you do not touch the pins or printed conductors when you
pick up flat modules. 2
Do not touch components unless 2
Å you are constantly earthed by an ESD wrist strap or
Å you are wearing ESD shoes or ESD shoe earthing strips on an ESD floor.
2
Always discharge yourself before you touch an electronic module. To do this, simply touch a con-
ductive and earthed object immediately before you touch the module (such as unpainted parts of
a switch cabinet, a water pipe, etc.). 2
User Manual HS-50 2 Operational Safety
Software Version SR.501.xx 12/99 Issue US 2.7 ESD guidelines
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t IIt
Do not allow modules with chargeable and highly insulating materials to touch one another, e.g.
plastic films, insulating table surfaces or items of clothing made from synthetic fibers. 2
Always place the modules on a conductive surface (table with an ESD coating, conductive ESD
foam, ESD bag or container). 2
Do not bring modules near visual display units, monitors or televisions. Keep them at least 10 cm
away from the screen. 2
2.7.4 Measurements and modifications to ESD modules
Do not take measurements on such modules unless
Å the measuring device is earthed (e.g. via PE conductors) or
Å you discharge the measuring head just before taking measurements with a potential-free mea-
suring device (e.g. by touching an unpainted metal part of the controller casing).
Å Always use an earthed soldering iron if you carry out any soldering work.
2.7.5 Dispatching ESD modules
Å Always store modules and components in conductive packaging (e.g. metallized plastic bags
or metal sleeves) and dispatch them in conductive packaging.
If the packaging is not conductive, place the modules in a conductive envelope before pack-
aging. (Use ESD bags, domestic aluminum foil or paper, for example. NEVER use plastic bags
or film). 2
Å If the module has integral batteries, ensure that the conductive packaging does not touch or
short-circuit the battery terminals and, if necessary, first cover the terminals with insulating tape
or material.
2