Instrument Programming
Page 28
August 2019
DPP-UM-00256-EN-03
Oate Pulse Output Module
The Rate Pulse Output Module is used to transmit information to external counters and PID systems via a frequency output
that is proportional to system flow rate The frequency output range of the Rate Pulse Module is 0…2500 Hz This module has
two types of outputs: one simulates the output of the coil of a turbine flow meter and the other is an open-collector type that
does not source voltage at its output Both outputs may be connected simultaneously
The turbine meter output creates a 500 mV peak-to-peak saw-tooth waveform that is not referenced to ground This output
can be run to electronic monitors that are compatible with variable reluctance outputs from coils, such as those found in
turbine and paddle-wheel flow meters The input impedance of the receiving device should not be smaller than 2000 Ohms
The standard pulse output does not output a voltage, but acts as an open-collector output requiring an external power
source and pull-up resistor See
The MOSFET in the Rate Pulse Module can support loads of 100V @ 1 A Resistor
selection is based on the input impedance of the receiving device Select a resistor that is a maximum of 10% of the input
impedance of the receiving device, but does not exceed 10k Ohms
0
500 mV
p-p
0
+V
RTU/PLC
MONITOR
TURBINE IN
TURBINE IN
RTU/PLC
MONITOR
PULSE IN
+V EXT SENSOR
GND
0
TIME
+V
R
500 mV
pp
TURBINE - B
TURBINE - A
IN (+)
OUT (-)
I/O: 0-2.5KHz
P.N. D020-1045-207
ISO
-MOD
Figure 26: Rate pulse module
