Spacelabs 91518, Руководство по обслуживанию

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Maintenance
91518 Multigas Analyzer Service Manual 4-16
Firmware Updates
When necessary, firmware updates to the 91518 Multigas Analyzer are made by PCBA replacement.
Corrective Maintenance
Corrective maintenance begins with initiating actions to determine the equipment’s state of functionality. This
usually begins with questioning the clinical user in the degree of equipment functionality and the type of
problem encountered.
Functional Performance Check
Part of the examination is a functional performance check.
Refer to Functional Performance Check on page 4-2, and perform the procedure. The functional performance
check is always performed before and after the preventive maintenance procedure, and before and after the
corrective maintenance procedure.
Service Calibration Mode
Warning:
The calibration gas used in these procedures contains an anesthetic agent that must be vented
away from users. You must either complete these procedures in a well-ventilated space or connect
the scavenge port and excess flow lines to an exhaust hood or gas-scavenging system.
Gas Calibration
The calibration process utilizes a very specific and accurately proportioned mixture of anesthetic agent, N
2
O,
CO
2
, and either O
2
or N
2
against which the 91518 is standardized. The calibration gas is supplied in a canister
with a limited amount of gas.
When the calibration sequence begins, a detailed analysis of the incoming gas is performed. The 91518
software contains the exact numeric values for the various gases that are documented on the sample bottle.
Initially, the 91518 examines the contents of the measurement chamber for the specific signature of each gas
and compensates for any difference between the measured value and the expected value. These correction
factors are stored in non volatile memory for subsequent use.
Note:
The numeric values that are displayed following a successful calibration do not need to exactly match the
nominal values listed on the sample bottle. This is due to small ongoing variations in flow, pressure, and
temperature for both the source gas and the measurement chamber. However, if the initial error is larger
than 20%, a second calibration may be necessary to reduce the remaining error to insignificance.
When calibrating, it is recommended that you use a full bottle that has stabilized at a temperature of 21° to
32° C (70° to 90° F) for at least 24 hours.
Note:
Bottles that have been exposed to and have attained a temperature below 0° C (32° F) should never be
used for calibration due to the destructive nature of extremely cold temperatures on the gas mixture.