Used with all Daniel turbine flow meters, the Universal Preamplifier converts the flow meter’s low-voltage signal output to high-voltage pulses. This amplifier conditions the pulse, enabling users to connect the meter to flow computers and correctors. It is distinguished by:
Tailored frequency response
The sensitivity of the Preamp rolls off as frequency increases, matching the characteristic output of a turbine meter with inductive pickup. High sensitivity at low frequencies allows the turbine meter to operate at its lowest possible flow rates. Reduced sensitivity at high frequencies prevents spurious counting due to RFI and transients.
Common mode rejection
The Preamp employs a differential amplifier, which responds only to differences between the COIL+ and COIL- wires. Spurious signals such as 60Hz, RFI, or transients typically appear on both wires as “common mode” signals. The Preamp is hundreds of times less sensitive to common mode signals than to the “normal mode” signals produced by the meter.
With its dual outputs, the preamp works with virtually any end device. One output swings from 0V to 5V regardless of the power supply voltage, and is suited for most inputs with thresholds of 4V or less. An open collector output swings from 0V to any available power supply voltage up to 36V, sinking up to 50mA.
Wide power supply range, low power operation
The preamp operates with any power supply voltage from 5.4 to 36V and requires less than 1mA. It can be added to virtually any system without special power conditioning, and typically with no impact on power system requirements.
The preamp tolerates continuous short circuits to ground or up to ±36V on any field wiring terminal without damage. All field wiring terminals are protected against ESD (electrostatic discharge) and transients.
Rugged and convenient packaging
The preamp is fully encapsulated in a compact package suitable for mounting on a panel or in a standard 3” ID explosion-proof housing. Pluggable cage-clamp type connectors allow convenient, reliable connections without the need for lugs. Terminals are labeled with signal names to simplify installation.