Flowmeter Input
19
7. FLOWMETER INPUT
The Model 214Di 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.