Siemens SINUMERIK 840C - Manual (Page 22)

1 Prerequisites and Visual Inspection 11.92
1.2.1 Information on module handling
1.2.1 Information on module handling
• Synthetic or rubber soling, and in particular flooring and carpeting, may produce static
charges of several kilovolts in human beings. Integrated circuits are sensitive to this kind of
high voltage discharge.
• Electrostatic charging can cause damage even when the control is switched off. Short-
circuiting across the VCC RAM printed conductors, for instance, can corrupt the data
stored in the battery backed CMOS RAM chips or even cause the printed conductors to
burn out.
• The safety measures listed below must therefore be carefully observed in order to avoid
damage caused by improper handling.
• Never touch the printed conductors or components without first discharging on a grounded
system part.
• Remove or insert modules and power supply cables only when the control is switched off.
Note:
If modules have to be replaced or should a malfunction occur, always make sure that all
ICs are inserted properly and in the right place.
Special instructions regarding the handling of modules equipped with MOS chips:
MOS is a technology used to produce LSI digital circuits. "MOS" stands for Metal Oxide
Semiconductor.
The principle advantages of MOS technology are:
• Simple transistor design
• High component density
• Extremely low power consumption
There are special safety regulations for modules equipped with MOS chips. These modules
are thus specially marked:
Identification
on packaging: Caution!
Observe safety
regulations!
Identification on the PCB:
MOS MOS
M
O
S
The printed circuit board is fitted with MOS chips. To prevent these
chips from being irreparably damaged, equipotential bonding must be
ensured prior to installing the PCB. Remove the PCB together with the
conductive foam plastic from the packaging and touch a part of the
system that has been grounded.
Do not touch the printed conductors or components!
1–2 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)