GE Voluson 730, Руководство по обслуживанию

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GE M
EDICAL
S
YSTEMS
- K
RETZTECHNIK
U
LTRASOUND
D
IRECTION
105844, R
EVISION
1 V
OLUSON
® 730 S
ERVICE
M
ANUAL
2-4 Section 2-2 - General Console Requirements
2-2-3 EMI Limitations
Ultrasound machines are susceptible to Electromagnetic Interference (EMI) from radio frequencies,
magnetic fields, and transients in the air or wiring. Ultrasound machines also generate EMI. The
Voluson® 730 complies with limits as stated on the EMC label. However, there is no guarantee that
interference 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 a defect. These
sources include:
• medical lasers,
• scanners,
• cauterizing guns,
• computers,
• monitors,
• fans,
• gel warmers,
• microwave ovens,
• light dimmers
• portable phones.
The presence of a broadcast station or broadcast van may also cause interference.
See Table 2-4 for EMI Prevention tips.
Table 2-4 EMI Prevention/Abatement
EMI Rule Details
Be aware of RF sources
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.
Ground the unit
Poor grounding is the most likely reason a unit will have noisy images. Check grounding of the
power cord and power outlet.
Replace all screws, RF
gaskets, covers, cores
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.
Replace broken RF gaskets
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.
Do not place labels where
RF gaskets touch metal 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.
Use GE specified harnesses
and peripherals 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.
Take care with cellular
phones
Cellular phones may transmit a 5 V/m signal; that could cause image artifacts.
Properly dress peripheral
cables
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.