GE Datex-Ohmeda Aisys Carestation Reference Manual page 59

Mixer Service /
Diagnosis and
Troubleshooting
M1046983 04/08
As the system cycles through its self-tests, the six LEDs may cycle on and off
throughout this process. It should also be observed the Valve 1 and Valve 2 LEDs cycle
On and Off during Checkout. More detail on the timing and operation these valves will
be covered later.
O and Balance Gas Mixer Valves (Valves 1 and Valves 2) are controlled by circuitry on
2
the Electronic Gas Mixer.
Anesthesia Control Board controls the O
The Sintered filters and check valves play critical roles in generating backpressure for
delta pressure signals for flow verifications. Since the check valves play critical roles in
generating backpressure for delta pressure signals for flow verifications, they are not
field replaceable.
Three normally closed gas selector valves, two Proportional Valves, and one normally
open Alt O Valve makeup the valves that control gas flow on the Electronic Gas Mixer.
2
The Electronic Gas Mixer is a field replaceable unit and comes pre-calibrated. The
valves are field replaceable, as well as the cables that interconnect the Electronic Gas
Mixer assemblies.
The ONLY field calibration is the pressure transducers zero. Basic flow checks can be
done in the service application.
Mixer CPU POST tests:
• Memory and CPU tested
• Communications tested
• Sensor validity tested
• Reference Voltage tested
Gas Tests:
• Alt O Valve Leak Test
2
• Prop Valve Leak Test
• Flow Verification Tests
• Selector Valve Leak Tests
• Balance Gas Check Valve Leak Test
Failure of any POST Test will render the Electronic Gas Mixer as failed and the Alt O
be enabled if the case is started.
CPU Tests include:
• EEPROM holds the flow and pressure calibrations (this is CRC tested);
• RAM stores Temp calculations;
• Registers arithmetic operations
Communication tests include:
• Serial communication check between Electronic Gas Mixer CPU and TSI Flowmeter
board;
• Serial communication check between Electronic Gas Mixer CPU and Anesthesia
Control Board.
2 Theory of Operation
, Air, and N O Selector Valves.
2 2
will
2
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