Datex-Ohmeda S/5 G-AO, Техническое справочное руководство, Страница: 66 / 83

Datex-Ohmeda S/5 Anesthesia Monitor
Document No. 800 1005-1
60
Calib zero and gain
These values are calibration constants of zero and gain for each gas. The zero values may change
at gas zeroing, the gain values at gas calibration.
When the monitor performs gas zeroing, the main software will write zero constants for the gases
(CO
2
, N
2
O, AA, O
2
) to the ACX memory. If some dust (or water) has entered the measuring chamber,
zeroing of the gases require higher zero constants than before depending on the contamination
level. If some gas requires higher value than 65536 the unit is not able to perform the zeroing and
the message ‘XXX ZERO ERROR’ appears to the error list and the software recalls the previous zero
constant for the concerned gas. If this happens at the initial start up the software will not pass the
“calibrating gas sensor” state.
The N
2
O zero point is very sensitive for the measuring chamber contamination. Therefore the zero
constant of N
2
O can be utilized in observing the contamination level of the ACX measuring
chamber. The optimum value for the N
2
O zero constant with new and clean measuring chamber is
45000 indicating the ratio of 1:1 between the measuring and reference channel signals. The
maximum acceptable value for the N
2
O zero constant is 51000, for a new measuring unit. The
maximum value that the main software is able to set is 65536.
Exp, Insp
Gas concentration value from the ACX measuring unit.
Pressures
Ambient
is the ambient pressure measured at the initialization. Work press is the internal pressure
of sampling system measured by the ACX measuring board pressure transducer. The difference
between these two pressures is Amb-Work and if the pump is functioning, it should normally be
within 50...75.
OM(in-ref) is a pressure difference between the O
2
measurement flow and the O
2
reference flow.
This pressure difference is automatically checked after every gas zeroing and it should be between
5 to 10 mmHg. If the pressure difference turns negative a message ‘Replace trap’ is displayed
when the limit of -5 mmHg is exceeded.
In S-___97 and S-___98 software there is a software flaw in displaying the pressure difference, OM (in-ref). The flaw does not have any
effect on the functioning of the ACX unit. The operational limit for the ‘Replace Trap’ message is -5 mmHg as in previous SW versions.
The flaw is only in the displaying of the pressure difference value. With S-___97/98 software the pressure difference can be checked in
a following way: turn the pressure valve ON for five seconds. This enables the updating of the OM (ref) value. Turn the pressure valve OFF
and wait for five seconds. Now calculate the difference between Work press and OM (ref).
Pump, zero valve , and pressure valve are operated manually by highlighting and pushing the
ComWheel. During patient monitoring, the valves are in OFF position
ACX temp indicates temperature inside the ACX bench, and the value is typ10 ° C higher
than the prevalent room temperature.
Delays indicate the time delays within or between measurement units.
Delays are measured at the same time as fall times.
Check that the ACX_ASX delay is between 400-800.
NOTE: The measurement can be performed only with the modules using module software 884295.
Timeouts is a cumulative number that indicates how many times the module has not responded to
the monitor’s inquiry.
Bad checksums is a cumulative number that indicates how many times communication from the
module to monitor broke down.
Bad c-s by mod is a cumulative number that indicates how many communication errors the
module has detected. The monitor starts counting these items at power up and resets to zero at
power off. The nonzero values do not indicate a failure, but the continuous counting (more than 50
per second) indicates either serial communication failure or module not in place.