Philips M3015A - Page 168

Preventive Maintenance Tests
152
Testin
g
the Instrument
Noise Check
Step 1 Check that the Monitor is in Service Mode and in the CO
2
window.
Step 2 Disconnect the flowmeter and connect the 5% calibration gas and flow regulator in
its place.
Step 3 Open the valve to apply the 5% Calibration Gas and wait until the value is stable.
Step 4 Check the Noise Index (x6) displayed next to the CO
2
value on the M3046A display
(this indicates the level of noise on the CO
2
wave). If the value exceeds 3 mmHg the
M3015A unit must be replaced.
CO
2
Gas Measurement Calibration Check
After switching the Measurement Extension on, wait at least 20 minutes before checking the
calibration.
Check the calibration of the CO
2
Gas Measurement as follows:
Step 1 Check that the 5% calibration gas and flow regulator are connected.
Step 2 Calculate the expected measurement value in mmHg as follows:
0.05 x (ambient pressure) = value mmHg
e.g. 0.05 x 736 = 36.8 mmHg (with an ambient pressure of 736 mmHg)
Step 3 Open the valve on the flow regulator to allow 5% CO
2
gas to flow into the
Extension. Allow the value to stabilize.
Step 4 Check that the value on the instrument (measurement value on the Main Screen,
x7)) matches the calculated mmHg value ± 2.6 mmHg. If the value is outside the
tolerance, calibrate as described in Step 9 onwards.
Step 5 Disconnect the 5% calibration gas and connect the 10% calibration gas.
Step 6 Calculate the expected measurement value and tolerance in mmHg as follows:
0.1 x (ambient pressure) = value mmHg
±0.07 x (value mmHg) = tolerance
e.g. 0.1 x 737 mmHg = 73.7 mmHg (with an ambient pressure of 737 mmHg)
±0.07 x 73.7 mmHg = ±5.16 mmHg tolerance
Step 7 Open the valve on the flow regulator to allow 10% CO
2
gas to flow into the
Extension. Allow the value to stabilize.
Step 8 Check that the value on the instrument (x8) matches the calculated mmHg value
within the calculated tolerance. If so, the Measurement Extension is correctly
calibrated. If the value is outside the tolerance, calibrate as follows
Step 9 If not already connected, connect the 5% calibration gas.
Step 10 Select Cal. CO
2
.