Amplifier Board

The Amplifier Board provides a 5V square wave pulse from the standard GL Flow Turbine, with the same frequency as the input signal.


Supply Voltage 8 to 28 V ( regulated D.C. Supply )
Input Signal 5 mV to 5 V rms
Frequency Range 10 Hz to 5000 Hz
Input Sensitivity 5 mV rms at 100 Hz
Output Signal 5 V square wave

Scaler Board

The Scaler Board is designed to enable a volt – free pulse to be produced from the standard G L Flow Turbine. The circuit counts input pulses from the Turbine Meter and produces an output pulse every time it reaches the scale factor. It has the facility to scale the Flowmeter input to provide a suitable volt – free pulse output.

By referring to the Flowmeter Calibration Sheet (pulse per litre, gallon etc.), it is possible to calibrate the Scaler Board at a given flow rate or over the full flow range of the Turbine.


Supply Voltage 8 to 28 V (regulated D.C. Supply)
Current Dissipation  50 mA (max)
Max. Switch Operation  2.5 Hz with 1 : 1 mark space ratio
Pulse Width  200 mS (on time)
Max. Switch Voltage  200 V D.C.
Max. Switch Current  250 mA
Max. switch Power  3A

Accessories - F / I ( 2 ) Board

The F / I ( 2 ) Board converts the frequency produced by a standard GL Flow Turbine into a 2 wire, 4 – 20 mA signal.

4 mA represents zero flow and 20 mA represents full flow, or can be scaled to a lower value if required (subject to the specifications, below).

Setup is simply achieved by adjusting 4 rotary decimal switches to the frequency corresponding to the maximum flow rate.


Supply Voltage 8 to 30 V ( regulated D.C. Supply )
Input sensitivity  5mV r.m.s at 100Hz
Frequency range  5Hz – 10KHz
(Frequencies < 5Hz will produce a 4 mA signal)