White Filter Check / Filter Initialization - BRECHTEL STAP 9406 Instrument Manual

7 Operating the STAP
7.3 White filter check / filter initialization
The white filter check (called filter initialization in the STAP firmware) is a baseline
measurement of the intensity measured by the detectors with a new filter using particle-
free air. It is important to establish a baseline range for the instrument.
The STAP must be warmed up for at least 10 minutes before performing a white filter test
and before acquiring data. First, ensure that a filter is installed on the input flow to the
sample LFE. A canister filter has been supplied for this purpose. Install new filters in the
STAP, power on the STAP and turn STAP CONTROL to 'On' in the control software. Turn
the black data knob clockwise to begin the white filter check. A 10 minute warm up period
will occur before the filter check. If the unit is already warmed up, the 10 minute warm
up period can be skipped in the software by turning the black data knob appropriately.
The instrument will notify the user when the white filter check is complete, so that the
user can remove the filter from the inlet and begin normal sampling. The check normally
requires 10 minutes after the warm up period ends.
When the STAP is turned on after having been off for an extended period it is important to
allow it to warm up before taking readings or doing the white filter initialization. When
an initialization is completed, the readings and LED settings for that initialization are
stored in the onboard EEPROM memory. In this way, the STAP can recover from a power
outage without going through another white filter initialization.
The "fltstat" parameter (short for filter state) is accessible via the serial port. The fltstat
can have the following values.
0 = PREVIOUS (use the initial values read from EEPROM)
1 = INSTALL_HEPA (waiting for user to confirm HEPA filter is installed)
2 = WARMUP (10 minute warm up, this state can be skipped if unit is already warmed up)
3 = RESET_LEDS (resets the LED power levels to 0)
4 = ADJUST_LEDS (adjust the LED brightness)
5 = READING_INIT (take initialization readings)
6 = REMOVE_HEPA (waiting for user to confirm HEPA filter is removed)
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