MASS-tron II/CEM
Air Monitor Corporation
116-004-94.P65 (8-31-10)
MASS-tron II/CEM
- IO&M Manual
3 – FEATURES
3.1 – OPERATOR SETUP MENU
The microprocessor program contains a Operator Setup menu system for setting user selectable parameters. Four
pushbuttons,
ESC, UP, DN, ENT
, allow the user access to the menu for setting configuration modes and values. Refer
to the Configuration Programming (Section 5.6) instructions for operation details. Also contained in the Operator Setup
menu is all input and output calibration. The calibration method is completely digital and contains no analog potentiometer
adjustments which are susceptible to drift. Non-volatile memory is used for storing all setup parameters and calibration
values, and will remain unchanged after set, even when power to the unit is off.
3.2 – 40CFR75 COMPLIANT
The MASS-tron II/CEM is designed to provide all functions and meet all data reporting requirements specified under
40CFR75: signals (4-20mADC standard; 0-5V or 0-10V optional) of mass flow and temperature; daily AUTO-cal reporting
of transmitter zero and span drift; daily AUTO-purge of flow sensors; AUTO-purge in progress acknowledgment; and
AUTO-cal in progress acknowledgment. AUTO-cal and AUTO-purge cycles can be internally timed or externally activated,
with selection via Operator set-up menu.
3.3 – AIR DENSITY CORRECTION
The MASS-tron II/CEM transmitter is capable of performing both process temperature and process static pressure
correction. Temperature input is an analog signal from a remote temperature device; non-linear temperature inputs can
be linearized by the microprocessor. Process static pressure is measured by means of an internal absolute pressure
transmitter connected to the transmitter static pressure signal input.
3.4 – TRANSMITTER HOLD
Certain operations performed by the microprocessor place the unit into a
Hold
mode. This occurs when the Operator
Setup menu system is activated, when an AUTO-zero is performed, when an AUTO-cal is performed, or when an AUTO-
purge cycle is in progress. When in
Hold
, all
Normal
mode processing is halted and outputs are held at their last value
prior to
Hold
.
Normal
operation is indicated by the "CPU Activated" LED flashing at a rate of four times per second. A
Hold
mode is indicated by the "CPU Activated" LED flashing at a rate of one flash per second.
3.5 – AUTOMATIC ZEROING
At periodic intervals the microprocessor will automatically execute an AUTO-zero cycle consisting of the following
sequence: The transmitter output and display signals are put on
Hold
; a valve is activated which disconnects the
process high pressure from the high port of the transducer and connects the process static pressure to both sides of
the transducer, creating a true zero differential pressure; after a brief stabilization period, the transducer zero offset
signal is measured and stored in memory; the valve is deactivated and after a brief period for process signal stabilization,
the
Hold
is released and
Normal
process measurement resumes. During
Normal
operation, the zero offset value stored
in memory is subtracted from subsequent transducer readings until the next AUTO-zero cycle occurs and repeats the
process. AUTO-zero On/Off and Interval are available and configurable using the Operator Setup menu.
3.6 – AUTO-purge MANAGEMENT
For "dirty process air" applications requiring the use of an Air Monitor AUTO-purge system, the MASS-tron II/CEM
along with a "smart" relay provides the capabilities of establishing purge frequency and duration, while also giving the
user a choice of either internally timed cycle frequency or externally triggered purge initiation. During the purge cycle
all transmitter outputs are maintained at their last value prior to the start of the purge cycle.
3
SECTION 3 – FEATURES
Summary of Contents for MASS-tron II/CEM
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