Mallinckrodt NELLCOR NPB-4000 Service Manual page 40

Section 4: Power-up Defaults Menu and Diagnostic Mode
4.3.4 NIPB Test
4-6
An NIBP Test screen is provided to facilitate troubleshooting problems and
performing verification testing for the NIBP subsystem. Typically, when these
tests are performed, the pneumatic system is connected to an external pressure-
reading device and a closed reference volume. The NIBP Test screen provides a
real-time numeric display of the pressure in the pneumatic system, means for
controlling the pump and valves, and a display indicating whether the
proportional and safety valves are open or closed.
Warning: A blood pressure cuff, connected to the monitor, should never be
applied to a human subject while the monitor is in Diagnostic Mode, as
injury could result.
The NIBP Test screen elements are described below:
• Pressure Display: The real-time value of the system pneumatic pressure is
displayed in mmHg. The value is updated at the rate of approximately two
times per second.
• Proportional Valve Display: The display indicates whether the proportional
valve is open or closed.
• Safety Valve Display: The display indicates whether the safety valve is
open or closed.
• Activate pump: For as long as the NIBP Start/Stop switch is pressed, the
pump will run. If system pressure reaches the hardware over-pressure
protection point (280 to 330 mmHg), the safety valve will open and the
pump will be disabled, until the pressure falls below the safety threshold.
• Deflate: For as long as the Alarm Silence switch is pressed, the proportional
valve will open and bleed off pressure at the rate of 3 ±1.5 mmHg/sec.
• Open Both Valves: For as long as the Heart Rate Tone Volume switch is
pressed, the safety valve and proportional valve open to maximum and
remain so for as long as the switch is pressed.
• Offset Adjust: A momentary press of the Contrast Adjust switch will
invoke the "zero calibration" routine that is performed immediately prior to
each blood pressure measurement. This routine looks at the pressure in the
system, and if the pressure is non-zero, an offset is applied which causes the
system pressure to be displayed as "zero".
• When in the NIBP Test screen, the "Return" item is always highlighted; a
press of the knob will return the user to the Diagnostic Menu. Rotating the
knob while in the NIBP Test screen will have no effect.