Chapter 1: Functional Description
Servo Controlled Oxygen Option
Service Manual
1-7
The RS-232 Board contains the electronic circuitry necessary to provide a 1500 VRMS isolated serial
interface which meets the EIA/TIA-232E specification and a 1500 VRMS isolated single-pole double-throw
(SPDT) relay. The relay contacts are rated for 24 VDC and 0.5 amps of current.
For further details on the connector pinout and DataLink data protocol, see “RS-232 Serial Data” on page C-
1 for more information.
Note:
The Ethernet port is not functional, the USB port may be activated only while in Service Mode for the
purpose of software update.
1.8 Servo Controlled Oxygen Option
The Giraffe Servo Control Oxygen System consists of an oxygen sensing circuit, Servo Oxygen circuit board,
and an oxygen delivery system.
The sensing circuit is located beneath the bed and consists of a pair of fuel cell oxygen sensors, a three-way
solenoid calibration valve, and a calibration fan. In normal operation the calibration valve is closed and
allows the Giraffe fan to circulate gas from the patient compartment across the sensors.
Note:
During the first 90 minutes of operation unit will not allow you to turn off air boost. To override this
feature, refer to “Figure 2.2.4.2 Vent Fitting to O2 Sensor Leak Test” for details.
Reference GSOCs in the user manual.
The device must be calibrated at least every 24 hours when servo oxygen is in use. After 24 hours have
elapsed the system prompts the user to perform calibration. Once the operator initiates calibration, the
calibration valve opens and the calibration fan is turned on. This draws ambient air across the sensors until
a stable reading is obtained. This 21% oxygen reference value is then used to calibrate the measuring
algorithm. After calibration 100% oxygen is briefly delivered to the system to ensure there are no
occlusions. When calibration is complete the device will resume controlling oxygen based on the last set
point.
The system must have two sensors present to operate. One sensor is always used for control and the other
is used for a redundant check and display. The sensors generate a voltage of about 5 millivolts at 21%
oxygen concentration and about 90 millivolts at 100% oxygen concentration. The voltage is directly
proportional to the concentration of oxygen. Humidity and temperature sensors located in the sensor plug
are used for voltage compensation. A fan mounted to the sensor-housing panel is activated when the
temperature reaches 50 degrees C. This fan circulates air to keep the sensors below the maximum
allowable operating temperature, about 55 degrees C.
The Servo O2 board is located in the Giraffe controller enclosure. The microcontroller and integrated EPROM
on the board perform the following:
•
Convert sensor output from analog to digital.
•
Activates oxygen alarm conditions.
•
Two-way communications via RS-485 bus with the Giraffe control board.
•
Controls the calibration valve to select calibration mode.
•
Controls the two supply valves to maintain the desired oxygen set point.
•
Opens the safety relay, which removes power to the three-way valve and the supply valves in case
of a system failure.
The oxygen delivery system consists of two solenoid supply valves, and a regulator assembly. The preset
regulator regulates the oxygen supply to 345 kPa (50 psi). Two supply valves, controlled by the Servo Oxygen
Содержание Giraffe OmniBed Carestation CS1
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Страница 40: ...Safety and Regulatory Information User Responsibility xxiv Service Manual ...
Страница 44: ...Chapter 1 Functional Description Control Board 1 2 Service Manual FIGURE 1 1 Block Diagram ...
Страница 74: ...Chapter 3 Calibration and Maintenance Line Voltage Calibration 3 12 Service Manual ...
Страница 82: ...Chapter 4 Understanding the Service Interface Upgrade 4 8 Service Manual ...
Страница 110: ...Chapter 5 Troubleshooting Diagnostic Readings 5 28 Service Manual ...
Страница 211: ...Chapter 7 Repair Procedures Display Harness Connections Service Manual 7 75 ...
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Страница 272: ...Chapter 8 Illustrated Parts Options 8 60 Service Manual FIGURE 8 36 Silo Support Assembly 6600 0853 800 ...
Страница 290: ...Chapter 8 Illustrated Parts Wiring Diagrams 8 78 Service Manual FIGURE 8 45 Wiring Diagram Control Panel ...
Страница 291: ...Chapter 8 Illustrated Parts Wiring Diagrams Service Manual 8 79 FIGURE 8 46 Wiring Diagram Incubator and Warmer Heater ...
Страница 292: ...Chapter 8 Illustrated Parts Wiring Diagrams 8 80 Service Manual FIGURE 8 47 Wiring Diagram Servo Humidifier ...
Страница 293: ...Chapter 8 Illustrated Parts Wiring Diagrams Service Manual 8 81 FIGURE 8 48 Wiring Diagram Servo Control Oxygen ...
Страница 294: ...Chapter 8 Illustrated Parts Wiring Diagrams 8 82 Service Manual ...
Страница 296: ...Appendix A Compartment and Skin Probe Characteristics A 2 Service Manual ...
Страница 304: ...Appendix C RS 232 Serial Data Nurse Call C 4 Service Manual ...