Dwyer Instruments UFM2 - 4 Outputs; Pulse Output; Volumetric Pulse

UFM2/UBT User Manual
Page 28 Issue 1.1b July 20
4 OUTPUTS
4.1 Pulse Output
Pulse output can be set up to operate one of five modes:
• Volumetric
• Energy (UBT only)
• Frequency
• Low Flow Alarm
• Loss of Flow (Signal) Alarm
The Alarm functions allow you to set the alarm switch to Normally Open or Normally Closed.
4.1.1 Volumetric Pulse
The default pulse width is set to 50ms which represents half of one pulse cycle. A 50ms pulse width
is required for most mechanical counters.
Formula to obtain Volume per Pulse based on a (default) 50 ms pulse width:
Volume per Pulse >= maximum flow rate (in litres per minute) / 600
Example for maximum flow rate of 500 USgal/min:
Volume per Pulse >= 500 USgal/min / 600 = 0.833 USgals per pulse
Rounding up to nearest whole litre:
Set Volume per Pulse to 1 USgal.
Pulse output
switch open
0
50
100
150
200
250
300
350
Time (milliseconds)
Pulse Width
50 milliseconds
Default Pulse Width
Pulse output
switch closed