Valleylab SurgiStat II, Service Manual

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3-4 SurgiStat II Service Manual
Alarm Tone
Patient Return Electrode Sensing
The system presents audible and visible alarms when it does not sense a patient
return electrode:
• When a fault condition occurs, the alarm indicator flashes red, an alarm tone
sounds, and the system disables output power.
• The red LED alarm indicator remains illuminated until you correct the
condition that caused the alarm condition.
• Activation attempts during an alarm condition result in an audio alarm and the
alarm indicator flashes.
• When the alarm condition is resolved, the green single or split-plate indicator
will illuminate.
• The system measures the return electrode sensing current according to
IEC 60601-1.
Volume (not
adjustable) 70 dBA ± 5 dBA
Frequency 2 kHz for 1 second, then
1 kHz for 1 second
Duration 4 seconds
Single-Plate Measurement current: < 100 µA
Measurement frequency: 62.5 kHz ± 2.5 kHz
Set resistance: 0
Ω
to 5
Ω
± 3
Ω
Continuous measurement:
Once the system establishes the single-plate electrode
resistance, an increase of 20
Ω
± 5
Ω
in resistance will
cause an alarm. When the alarm condition exists, the
system deactivates output power.
Split-Plate Measurement current: < 100 µA
Measurement frequency: 62.5 kHz ± 2.5 kHz
Set resistance: 10
Ω
± 5
Ω
to 135
Ω
± 10
Ω
Continuous measurement:
Once the system establishes the split-plate electrode
resistance, an increase of 40% in resistance or up to
150
Ω
(whichever is less) will cause an alarm. A
decrease of resistance below 4
Ω
± 2
Ω
will cause an
alarm. When the alarm condition exists, the system
deactivates output power.