WinSystems PCM-VDX-2-512, Руководство по эксплуатации продукта

Страница: 72 / 75

140808 PRODUCT MANUAL PCM-VDX-2-512 72
Contact Points
WinSystems’ boards mostly use connectors with gold finish contacts. Gold
finish contacts are used exclusively on high speed connections. Power and
lower speed peripheral connectors may use a tin finish as an alternative
contact surface. It is critical that the contact material in the mating connectors
is matched properly (gold to gold and tin to tin). Contact areas made with
dissimilar metals can cause oxidation/corrosion resulting in unreliable
connections.
Pin Contacts
Often the pin contacts used in cabling are not given enough attention. The
ideal choice for a pin contact would include a design similar to Molex’s or
Trifurcons’ design, which provides three distinct points to maximize the contact
area and improve connection integrity in high shock and vibration applications.
POWER DOWN
Make sure the system is completely off/powered down before connecting anything.
Power Supply OFF
The power supply should always be off before it is connected to the single
board computer.
I/O Connections OFF
I/O Connections should also be off before connecting them to the single
board computer or any I/O cards. Connecting hot signals can cause damage
whether the single board computer is powered or not.
MOUNTING AND PROTECTING THE SINGLE BOARD COMPUTER
Do Not Bend or Flex the SBC
Never bend or flex the single board computer. Bending or flexing can cause
irreparable damage. Single board computers are especially sensitive to
flexing or bending around Ball-Grid-Array (BGA) devices. BGA devices are
extremely rigid by design and flexing or bending the single board computer
can cause the BGA to tear away from the printed circuit board.
Mounting Holes
The mounting holes are plated on the top, bottom and through the barrel of the
hole and are connected to the single board computer’s ground plane. Traces
are often routed in the inner layers right below, above or around the mounting
holes.
Never use a drill or any other tool in an attempt to make the holes larger.
Never use screws with oversized heads. The head could come in contact with
nearby components causing a short or physical damage.
Never use self-tapping screws; they will compromise the walls of the mounting
hole.
Never use oversized screws that cut into the walls of the mounting holes.
Always use all of the mounting holes. By using all of the mounting holes you
will provide the support the single board computer needs to prevent bending or
flexing.