Service Manual HS60 - 第69页

Se rv ice M a nu al HS-6 0 2 Ope rati on al saf et y 03/ 200 3 U S Iss ue 2.9 ES D guid el in es 67 Alwa ys place t h e modules on a conductive surface (table with a n ES D coating, conductive ESD foam, ESD bag or contai…

2 Operational safety Service Manual HS-60

2.9 ESD guidelines 03/2003 US Issue

2.9 ESD guidelines

2.9.1 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). ’ESD’ is used inter-

nationally. The following symbol on cabinet rating plates, racks or packaging indicates that com-

ponents which are sensitive to electrostatic discharge have been used and thus that the modules

concerned 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 overvoltages do not generally appear to be defective immediately - incorrect

behavior starts after the component or module has been in operation for some time. 2

2.9.2 Important measures to protect against static charging

Æ Most plastics can easily become charged and must therefore be kept away from at-risk com-

ponents.

Æ Always ensure that people, the workplace and packaging are safely earthed when handling

electrostatic sensitive components.

2.9.3 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

Æ you are constantly earthed by an ESD wrist strap or

Æ you are wearing ESD shoes or ESD shoe earthing strips on an ESD floor.

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

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

Service Manual HS-60 2 Operational safety

03/2003 US Issue 2.9 ESD guidelines

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

2.9.4 Measurements and modifications to ESD modules

Do not take measurements on such modules unless 2

– the measuring device is earthed (e.g. via PE conductors) or

– 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).

Æ Always use an earthed soldering iron if you carry out any soldering work.

2.9.5 Dispatching ESD modules

Æ 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 packag-

ing. (Use ESD bags, domestic aluminum foil or paper, for example. NEVER use plastic bags

or film). 2

Æ 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 Operational safety Service Manual HS-60

2.9 ESD guidelines 03/2003 US Issue