Liquid Controls IT375 - Manual (Page 20)

Sponsler, Inc. Model IT375 Flowmeter Input Pg. 20
7. FLOWMETER INPUT
The Model IT375 has an input conditioning circuit which will accept signals from most sinewave or pulse producing
flowmeters. Links on the rear panel enable the input circuit to be configured for different signal types.
The input will interface directly to:
Turbine flowmeters.
Open collector outputs.
Reed switches.
Logic signals.
Two-wire proximity switches.
The following pages give examples of interfacing to various signal inputs. A circuit diagram of the input is also
provided.
For pulse or logic type signals, the input switching threshold is 1.3 volts. That is, the input signal must have a "low"
voltage of less than 1.2 volts and a "high" voltage of greater than 1.4 volts.
For flowmeters with reluctance type coils, the minimum input voltage is 15mVp-p
All inputs are protected for overvoltage up to 28 volts.