Yokogawa 202 Field Mounting Rate Totalizer - Manual (Page 30)

Flowmeter Input 26
7. FLOWMETER INPUT
The Model 202D has an input conditioning circuit which will accept signals from
most pulse or frequency 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 interconnection to various signal outputs.
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 coils, the minimum input voltage is 15mV P-P.
All inputs are protected for over voltage up to 28 volts.