Thermo Scientific Sarasota FD900, User Manual

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Thermo Fisher Scientific User Guide for Sarasota ID900, FD900, & PD900 Gas Density Meters
6-1
Chapter 6
Troubleshooting & Service
General
Troubleshooting
If unstable readings or readings of zero occur, complete these
troubleshooting steps. The symptoms listed in this section include:
●
Unstable readings
●
Meter readings at zero
●
Meter readings permanently at full scale
●
Meter readings vary with flow rate
Symptom:
Unstable readings
1. Ensure the Sarasota HME900 power supply links are correctly setup
for the supply voltage.
2. Ensure the computer or converter is set up correctly by checking
through the configuration data sheet. Check that the sensor serial
number calibration coefficients are the same as documented on the
calibration certificate.
3. If the readings are unstable, replace the computer. If using the Sarasota
HME900 and the period readings are stable, check the other variable
values used. If there are none, replace the SarasotaHME900.
4. If the time period and temperature readings are stable, check the signal
from the density meter. The voltage should be above 1 V p-p and stable
in frequency. If the voltage is below 1 V, check zener barriers and field
connections.
5. Check the current drawn by the density meter by inserting a milliamp
meter in series with the positive supply. A gas density meter about 20
mA. Also check the terminal voltages at the density meter amplifier
box. Voltage should be 25 V.
6. If readings are still unstable, remove the instrument. Clean it and check
the filter. Determine the cause of any buildup.