AEROCET 531S Manual Rev H
Page 30
8.2.
Zero Count Test
Air leaks or debris in the particle sensor can cause false counts which may result in
significant count errors when sampling clean environments. Perform the following zero
count test weekly to ensure proper operation:
1. Attach zero count filter to the inlet nozzle (PN G3111).
2. Configure the unit as follows: Sample Mode = MANUAL, Volume = Total Count
(TC), Measure = COUNTS.
3. Start and complete a sample.
4. The smallest particle size should have a count <= 1.
5. Run this test multiple times to flush out particles in the air stream if the goal is not
met.
8.3.
Flow Rate Test
The flow rate test verifies the sample flow rate is within tolerance. The reference flow
meter must be non-loading because the vacuum pump can be loaded down by external
restrictions. Met One Instruments sells a suitable flow meter (PN 9801). The flow rate
test follows:
1. Connect a ±3% reference flow meter to the sample inlet nozzle.
2. Configure the unit as follows: Mode = AUTO.
3. Start sampling.
4. The flow meter reading after ~3 minutes should be 0.1 CFM (2.831 LPM) ±5%.
5. Adjust the flow rate if the error is > ±5% (see section 5.8).
8.4.
Annual Calibration
The AEROCET 531S should be sent back to Met One Instruments yearly for calibration
and inspection. The annual calibration cannot be performed by the customer because
this calibration requires specialized equipment and a skilled technician. Met One
Instruments maintains a calibration facility for calibrating particle counters according to
industry accepted methods such as ISO and NIST. The annual calibration also includes
inspection and preventative maintenance to improve product reliability.
8.5.
Flash Upgrade
AEROCET 531S is firmware upgradeable via the serial connection using a Met One
Instruments flash burn program. Binary files and the flash program must be provided by
Met One Instruments.
