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

4. OPERATION
The CAT3-AC-MIL is an AC 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-AC-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
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
level square-wave
Operation
Microcontroller
Scaled Pulse Out
before sending
7
4-20mA
Loop Driver
it to the
HP-325