Dwyer TFM-LP - Manual (Page 14)

F-20-TF-L, pg. 14 of 30
a) 0-5VDC Analog Outputs
By monitoring the voltage output signal it is possible to determine the flow
rate of the liquid. Units are configured so that an output signal of 5.0VDC is
provided when the maximum flow (i.e. Full Scale flow) is passing through
the unit. The output signal is linear and scalable enabling calculation of flow
rates within the sensor’s range. For example:
For a flow range of 50-500ml/min:
At 500ml/min the output signal would be 5VDC
If the output signal were 3.5VDC then the flow rate would be:
500 ч 5 Ч 3.5 = 350ml/min
If the maximum flow rate is exceeded non-linear and inaccurate readings
will result.
b)
Pulse Outputs
By monitoring the Pulse output frequency it is possible to determine the flow
rate of the liquid. The pulse frequency for maximum flow through the unit
(i.e. full scale flow) is detailed on the calibration certificate. This differs from
unit to unit. This output is approximately linear and scalable within the
sensor’s range. For example:
For a flow range of 1.0-10.0l/min:
The calibration certificate gives the following:
At 10.0l/min the pulse output signal is 312Hz
At 5.0l/min the pulse output signal is 150Hz
At 2.0l/min the pulse output signal is 58Hz
If the output signal were 120Hz then the flow rate would be:
5.0 ч 150 Ч 120 = 4.0 l/min (using the closest calibration point)
c) Units With an Integral Display
The TFP-LI and TFM-LI Series feature an integral 3 ˝ digit LCD display. This is
configured to read in ml/min for flow ranges up to 50-500 ml/min and in
l/min for all other flow ranges. The display will only operate if power is
applied to the unit.