Instruction Manual

Copyright © 2006 CiDRA Corporation Page 10-8
20675-01 Rev 02
‘Flow Rate’, ‘Flow Rate %’, ‘SOS’, and ‘GVF’ generate a different
pulse output than ‘
Total Flow’ (‘Totalizer’). Flow Rate, Flow Rate %,
SOS, and GVF will output a pulse frequency based on the current
measurement. The
pulse width will vary in order to maintain a 50%
duty cycle pulse train.
Figure 62 Speed Of Sound and Gas Volume Fraction Pulse Output
‘Total Flow’ (or Totalizer) will output a number of pulses based upon
the total gallons (or flow units) counted during the previous update
interval (i.e. the display update time is defaulted to 2 seconds). In
effect, the Total Flow measurement is a pulse counter, updated at the
same time as the display.
Figure 63 Total Flow Pulse Output
SOS
Time (sec)
500 fps / 100 = 5 Hz
1000 fps / 100 = 10 Hz
300 fps / 100 = 3 Hz
Multiplier = 100
0
2
46
Pulse Width Varies
Total Flow (Totalizer)
Time (Update Rate = 2 sec)
0
2
46
(1500 gpm /10) / (60s/2s) = 5 (3000 gpm /10) / (60s/2s) =10 (900 gpm /10) / (60s/2s) = 3
Multiplier = 10
Pulse Width