TSI Incorporated 4140, Operation And Service Manual

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8 Chapter 3
port. Refer to the Series 4000/4100 RS232 Serial Command Set
manual for instructions on how to select between flow units.
The Model 4140/4143 has an independent temperature sensor in the
flow tube to measure the gas temperature. The temperature sensor is
used for temperature compensation of flow rate and for converting
flow from standard to volumetric units. Temperature can also be
displayed on the LCD and is available through the RS232 serial port
in the units of degrees Celsius (°C).
Note : At low flow rates, the temperature inside of the flow tube will
increase because of the heat generated by the thermal flow
sensor. This effect is normal and the temperature of the
incoming gas will be measured once flow resumes.
Pressure Measurement
The Models 4140/4143 measure absolute pressure near the outlet of
the flowmeter in the SI units of kilo-Pascals (kPa). Pressure
measurements are required when converting from standard to
volumetric flow. Absolute pressure can be displayed on the LCD and
is available through the RS232 serial port.
Select Measurement Displayed
By using RS232 commands the LCD display can be set up to
continuously display either flow rate, temperature, or pressure. See
the
SDMm command in the Series 4000/4100 Serial Command Set
manual.
Display “Scroll” Mode
By using RS232 commands the LCD display can be set up to
continuously scroll between flow rate, temperature, and pressure. The
scroll rate is adjustable and the user can specify the parameters to be
displayed. See the
SDMFTPn command in the Series 4000/4100
Serial Command Set manual.
Volume Measurement
These flowmeters measure total volume by integrating flow over time.
This is a calculated measurement performed by the flowmeter and is
only available using the RS232 serial port. Volume is not displayed on
the LCD display. Refer to the
Series 4000/4100 RS232 Serial
Command Set manual for instructions on using the volume function.