![background image](http://html1.mh-extra.com/html/sage/sie-series/sie-series_operation-and-instruction-manual_799925075.webp)
O p e r a t i o n s a n d I n s t r u c t i o n M a n u a l
75
S A G E M E T E R I N G , I N C .
REV. 03-SIE/SRE
What is a Thermal Mass Flow Meter?
FLOW SENSOR
(Self Heated)
TEMPERATURE SENSOR
(Reference Sensor)
• What is a Thermal Mass Flow Meter? It is a meter
that directly measures the gas mass flow based
on the principle of conductive and convective
heat transfer.
• All Meters have probes (Insertion Style) or Flow
Bodies (In-Line Style) that support a pair of
sensors, which are in contact with the gas.
• The sensors are RTDs, which are resistance tem -
perature detectors. They consist of highly stable
reference-grade platinum windings. In fact, we
use the same material that is used as Platinum
Resistance Standards at the NIST.
• The RTDs are clad in a protective 316 SS sheath
for industrial environments.
• One of the RTDs (See Diagram below) is self-heated
by the circuitry and serves as the flow sensor. The
other RTD acts as a reference sensor, and measures
the gas temperature. Essen tial ly it is used for tem-
perature compensation.
• The Sage proprietary sensor drive circuitry main-
tains a constant overheat between the flow sensor
and the reference sensor. As gas flows by the
heated sensor (flow sensor), the molecules of flow-
ing gas carry heat away from this sensor, and the
sensor cools down as it loses energy. The circuit
equilibrium is disturbed, and momentarily the
temperature difference between the heated sensor
and the reference sensor has changed. The circuit
will automatically (within 1 second) replace this
lost energy by heating up the flow sensor so the
overheat temperature is restored.
• The current required to maintain this overheat
represents the mass flow signal. There is no need
for external temperature or pressure devices.
Summary of Contents for SIE Series
Page 2: ......
Page 6: ......
Page 7: ...Section GETTING STARTED A ...
Page 8: ......
Page 23: ...Section STYLES AND FEATURES B ...
Page 24: ......
Page 28: ......
Page 29: ...Section DRAWINGS C ...
Page 30: ......
Page 39: ...Section USER INTERFACE D ...
Page 40: ......
Page 58: ......
Page 59: ...Section DIAGNOSTICS E ...
Page 60: ......
Page 63: ...Section WARRANTIES AND SERVICE WORK F ...
Page 64: ......
Page 69: ...G Section APPENDIX G ...
Page 70: ......