MASS-tron II/CEM
Air Monitor Corporation
116-004-94.P65 (8-31-10)
MASS-tron II/CEM
- IO&M Manual
1 – GENERAL INFORMATION
1.1 – DESCRIPTION
The MASS-tron II/CEM is an ultra-low differential pressure "smart" massflow transmitter designed to convert the low
magnitude pressure signals generated by airflow probes, plus process temperature and static pressure inputs into
analog output signals of mass flow, temperature, pressure, and transmitter drift. Each MASS-tron II/CEM is equipped
with numerous standard features: A multi-line LCD used during configuration/calibration and for display of process;
AUTO-zero for elimination of transmitter zero error; AUTO-cal to measure transmitter zero and span drift; user selectable
primary signal noise filter, input power isolation; capability of 10:1 flow or 100:1 pressure turndown; NEMA 1 enclosure,
and a long list of construction options.
1.2 – THEORY OF OPERATION
High and low pressure signals generated by airflow stations or probes act upon opposite sides of a flexible diaphragm
within the transducer. The differential between the two pressure signals displaces the diaphragm; the magnitude of the
displacement being measured creates an electrical DC output from the transducer. Additional analog signals of process
temperature (via external temperature input) and process static pressure (via internal absolute pressure transmitter)
are made available. After being multiplexed and undergoing A/D conversion, the resulting digital signals representing
process velocity pressure, temperature and static pressure can be manipulated within the microprocessor: square
rooted; density compensated for air temperature and air pressure correction; scaled for units of measure and area for
process outputs; filtered and scaled for local data display and utilized in performing a Special Function (see Section 3
– Features). The built-in microprocessor runs the program that provides the following basic functions: Timing, logic,
mathematical operations, analog input signal multiplexing, analog input/output calibration, digital input (contact closure)
detection, output relay operation, automatic zeroing valve operation, Operator Setup menu system, display (LCD)
indication, and individual LED indication.
1
SECTION 1 – GENERAL INFORMATION
Summary of Contents for MASS-tron II/CEM
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