Hoffer Flow Controls CAT3-DC-MIL User Manual page 15

3. OPERATION
The CAT3-DC-MIL is a DC powered microprocessor-based
transmitter, which provides pulse and analog outputs. The flowmeter
input circuitry will accept a magnetic type pickup, pulse and contact
closure. Optional 20-point linearization is available to correct for
flowmeter non-linearity, improving overall system accuracy.
CAT3-DC-MIL Block Diagram
Pickup Coil 1
Flow Sensor
4-1 Preamplifier
The Preamplifier receives signals from the flow sensor pick up coil.
The signal is amplified, filtered, and converted into a logic level
square-wave before sending it to the Microcontroller.
4-2 Microcontroller
The Microcontroller performs all of the calculations that are required to
control the analog output and pulse output. The following equations
are used to calculate the flowrate and the analog output current.
Preamp
Communications
Interface
RS232
Operation
Microcontroller
Scaled Pulse Out
7
4-20mA
Loop Driver
HP-324-5