Emi Limitations - GE Vivid P3 Service Manual

GE H
EALTHCARE
D 5344303-100, R
IRECTION
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EMI Limitations

Ultrasound machines are susceptible to Electromagnetic Interference (EMI) from radio frequencies,
magnetic fields, and transient in the air wiring. They also generate EMI. The Vivid P3 complies with
limits as stated on the EMC label. However there is no guarantee that interface will not occur in a
particular installation.
Possible EMI sources should be identified before the unit is installed.
Electrical and electronic equipment may produce EMI unintentionally as the result of defect.
These sources include:
• medical lasers
• scanners
• cauterizing guns
• computers
• monitors
• fans
• gel warmers
• microwave ovens
• light dimmers
• portable phones
• Lift
The presence of a broadcast station or broadcast van may also cause interference.
See Table 2-5 for EMI Prevention tips.
EMI Rule
Be aware of RF sources
Ground the unit
Replace all screws, RF
gaskets, covers, cores
Replace broken RF gaskets
Do not place labels where RF
gaskets touch metal
Use GE specified harnesses
and peripherals
Take care with cellular phones Cellular phones may transmit a 5 V/m signal; that could cause image artifacts.
Properly dress peripheral
cables
PROPRIETARY TO GE
3
EVISION
Table 2-5 EMI Prevention/abatement
Keep the unit at least 5 meters or 15 feet away from other EMI sources. Special shielding
may be required to eliminate interference problems caused by high frequency, high
powered radio or video broadcast signals.
Poor grounding is the most likely reason a unit will have noisy images. Check grounding of
the power cord and power outlet.
After you finish repairing or updating the system, replace all covers and tighten all screws.
Any cable with an external connection requires a magnet wrap at each end. Install the
shield over the front of card cage. Loose or missing covers or RF gaskets allow radio
frequencies to interfere with the ultrasound signals.
If more than 20% or a pair of the fingers on an RF gasket are broken, replace the gasket.
Do not turn on the unit until any loose metallic part is removed.
Never place a label where RF gaskets meet the unit. Otherwise, the gap created will permit
RF leakage. Or, if a label has been found in such a position, move the label.
The interconnect cables are grounded and require ferrite beads and other shielding. Also,
cable length, material, and routing are all important; do not change from what is specified.
Do not allow cables to lie across the top of the card cage or hang out of the peripheral bays.
Loop the excess length for peripheral cables inside the peripheral bays. Attach the monitor
cables to the frame.
Chapter 2 Pre Installation
V P3 S
IVID
Details
M
ERVICE ANUAL
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