MIL-STD-1330D(SH) APPENDIX D
w/ Change 1
7. THRESHOLD FOR PEAK: It displays the Threshold for Peak setting. Using the UP/DOWN buttons, set the Threshold for Peak to 1000 counts. The Threshold for Peak automatically triggers a peak search when the signal is cycled below this value. For instance, suppose that the Threshold for Peak is set at 30 counts, and that an evaporating dish is measured at 600 counts. When the dish is taken away from the sensor, the signal needs to decrease below 30 counts to initiate a search for a new reading. As long as it goes below 30 counts, when another dish is placed under the sensor, the unit will automatically search for a new peak. If it does not drop below 30 counts, a search for a new peak will not be initiated. Using the automatic mode can cause erroneous results for the use specified in this appendix. This is because the automatic peak search occurs very quickly and the dish or sensor may not be in place when the peak search is initiated. To force use in the manual mode, the Threshold for Peak is
set at 1000 counts. This will essentially inactivate the automatic feature and a peak search will begin when the
ENTER button is pressed.
8. SAVE CURRENT PARAMETERS: This screen will only be displayed if any of the preceding parameters were changed. Press the ENTER button to save changes.
D.8.3 Maintenance of SQM. Check the SQM UV lamp intensity, sensor electronics, and control unit electronics every six months using the following procedure and equipment listed in D.5.1(k), or by sending the entire unit (control unit and sensor) to the manufacturer. Log all results in data sheets 1 and 2. If the manufacturer performs the check, obtain the data and log in data sheets 1 and 2. Annotate any corrective action required in the Remarks column.
D.8.3.1 Sensor electronics.
D.8.3.1.1 Turn the SQM control unit ON. Allow 15 minutes to warm up. Confirm the monitor is in SIGNAL
mode.
D.8.3.1.2 Set the gain settings on the sensor and control unit to the settings used last time acceptance criteria were established for dishes.
CAUTION 2: When removing the sensor, do not touch the aperture on the end of the sensor. Contamination can seriously degrade performance.
WARNING 1: Do not look directly into the ultraviolet light source at the end of the sensor because it can cause eye damage.
D.8.3.1.3 Remove the screws holding the sensor in the stand and remove the sensor.
D.8.3.1.4 Place the Calibration Load (D.5.1(k)) at the end of the sensor. In order to read the calibration load, it needs to be held steady to yield stable readings. After the reading stabilizes, log the reading in data sheet 1.
D.8.3.1.5 Using the tool provided, increase the sensor gain by one unit from the setting of D.8.3.1.2 and repeat
D.8.3.1.4.
D.8.3.1.6 Using the tool provided, decrease the sensor gain by one unit from the setting of D.8.3.1.2 and repeat
D.8.3.1.4.
D.8.3.1.7 Referring to data sheet 1, for each set of gain settings, compare the first and last reading. If the reading drops by more than 5 percent, send the entire unit to the manufacturer for servicing. Note the first reading establishes the acceptance criteria and there is nothing to compare to. Also note that if the gain settings used for establishing acceptance criteria changed from the last time this calibration was accomplished, there will not be data to compare to for all of the readings; this is acceptable. When it gets returned from the manufacturer, repeat D.8.3.1.1 through D.8.3.1.7. This becomes the first reading.
D.8.3.1.8 Restore the gain settings on the sensor and control unit to the settings noted in D.8.3.1.2. Reinstall the sensor using the screws removed in D.8.3.1.3 and set the sensor per D.8.2.2.
D.8.3.2 UV lamp intensity.
D.8.3.2.1 Turn the SQM control unit ON. Allow 15 minutes to warm up.
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