CAMM
Air Monitor Corporation
116-044-91.P65 (8/31/10)
CAMM - IO&M Manual
1 – GENERAL INFORMATION
1.1 – DESCRIPTION
The CAMM is an ultra-low differential pressure "smart" mass flow transmitter designed to convert the low magnitude
pressure signals generated by airflow stations or probes, plus process temperature and static pressure inputs into
multiple output signals (4-20mA, 0-5VDC or 0-10VDC) linear to mass flow, temperature, and pressure. Each CAMM
is equipped with numerous standard features: A multi-line LCD used during configuration/calibration and for display
of process variables; AUTO-zero for elimination of transmitter zero error; AUTO-purge management; analog outputs
of flow (pressure), temperature, absolute pressure, and special function; Operator selectable primary signal noise
filter, input power isolation; and capability of 10:1 flow or 100:1 pressure turndown.
1.2 – THEORY OF OPERATION
High and low pressure signals generated by a combustion airflow station 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 4-20mA 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, and display (LCD) indication.
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SECTION 1 – GENERAL INFORMATION
Summary of Contents for CAMM
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