2-6
Brooks
®
Model SLA5840
Section 2 Installation
Installation and Operation Manual
X-PR-SLA5840-Series-RevB-RT-eng
Part Number: 541B201AAG
October, 2017
2-10 Operation Check Procedure
a. Mount the RT in its final orientation.
b. Apply power to the RT and allow approximately 45 minutes for the
instrument to completely warm up and stabilize its temperature.
c. Make sure the RT is set for flow mode.
d. Do NOT supply gas to the RT. Ensure that the differential pressure
across the RT is zero.
e. Check the RT zero.
f. The analog output signal should be 0.000 Vdc ± 0.2%. If the zero
exceeds one of these limits, follow the re-zeroing procedure in Section 3-4.
g. Turn on the gas supply. A positive flow signal may be present due to
slight valve leak-thru (RT only).
h. Supply a setpoint signal between 10% - 100%.
i. Check the analog output signal. The output signal should match the
setpoint voltage (± 0.2%) within 10 seconds after the setpoint is
changed.
j. If flow output signal does not match setpoint, and pressure settings
are correct, this could indicate a problem in the RT. A secondary
issue could be the gas type. When checking with a surrogate gas,
ensure that there is enough pressure to the RT in order to flow the
correct amount of the surrogate gas.
Example:
Checking an RT calibrated for 100 sccm SF6 (sulfur hexafluoride). The
sensor factor using N
2
(nitrogen) is 0.27, therefore the equivalent N
2
needed is 100/0.27 = 370.4 sccm. This may require a pressure
increase in order to meet the N
2
equivalent flow rate.
