2-5
Model SLA7840
Section 2 Installation
Installation and Operation Manual
X-PR-SLA7800-RT-eng
Part Number: 541B048AAG
August, 2009
2-11 Operation Check Procedure (Analog I/O)
a.
Mount the RT in its final orientation.
b.
Apply power to the RT and allow approximately one hour for the
instrument to warm up and stabilize its temperature.
c.
Do NOT supply gas to the RT. Ensure that the differential pressure
across the RT is 0 psid. Ensure that the RT is set for flow mode.
d.
Check the RT zero output signal.
e.
The analog output signal should be equivalent to 0.0 ± 0.2% FS
(0.000 ± 0.010 Vdc). If the zero exceeds one of these limits, follow
the re-zeroing procedure in Section 3-5.
f.
Turn on the gas supply. A positive flow signal may be present due to
valve leak-thru. At 0% setpoint the flow signal output < 0.5% FS
0.025 Vdc.
g.
If flow signal at 0% setpoint is > 0.5%, then there is too much
leak-through across the valve, and the RT would need a valve
valve adjustment.
h.
Supply a setpoint voltage between 1 and 5 Vdc.
i.
Check the RT analog output signal. The output voltage signal
should match the setpoint voltage (± 20mV) 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
The Brooks (electric/electronic) equipment bearing the CE mark
has been successfully tested to the regulations of the Electro
Magnetic Compatibility (EMC directive 89/336/EEC). Special
attention is required when selecting the signal cable to be used
with CE marked equipment.
Brooks supplies high quality cables which meet the
specifications for CE certification. If you provide your own signal
cable you should use a cable which is completely screened with a
100% shield. D-Connectors should also be shielded using a metal
shield. If applicable, metal cable glands must be used to provide
cable screen clamping. The cable screen should be connected to
the metal shell or gland and shielded at both ends over 360
degrees. The shield should be terminated to an earth ground. See
Appendix A for CE Certification of Mass Flow Equipment.
NOTICE
