PR 3225 Universal Frequency Converter

PR 3225 Universal Frequency Converter

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Product Overview

The PR 3225, a compact 6mm frequency converter, supports a broad range of industry standard input types, custom-programmable sensor voltages and output options:

  • Input: NAMUR, NPN, PNP, Tacho, TTL & S0
  • Output: Universal mA / V or relay
  • Power supply 16.8 VDC…31.2 VDC
  • Accuracy < 0.06% / span
  • Response time < 30 ms
  • 2.5 kVAC, 3-port galvanic isolation
  • Wide ambient temperature range -13…158°F
  • NAMUR NE21, NE43


  • Programmable f/I/U converter
  • Input: NAMUR, NPN, PNP, Tacho, TTL, & S0
  • Two output options – 3225A: mA / V, 3225B: Alarm relay
  • 0.001 Hz – 100 kHz input/output span
  • Response time < 30 ms
  • DIP-switch or display programmable
  • NAMUR NE21, NE43
  • 2.5 kVAC, 3-port galvanic isolation

Universal Frequency Converter

For easy deployment, the typical configuration can be achieved via DIP-switch programming. With the optional PR 4590 ConfigMate and communication interfaces in the PR 4500 series, it is easy to monitor and program the measurement point and take advantage of the advanced features supported by PR 3225.

Based on the strong foundation of the PR 3000 series with powerful features such as high accuracy, fast response time, and low temperature drift, the PR 3225 is a flexible and easy-to-use product when measuring frequency signals.

With outstanding EMC specifications that meet or exceed industry standards and its 5-year warranty, you can look forward to many years of trouble-free operation with PR 3225.

  • Measures frequencies up to 100 kHz
  • Active current output
  • Buffered voltage output 10 VDC
  • 2-point process calibration
  • User-programmable trigger levels -0.05…6.5 V and sensor supply 5…17 V
  • NAMUR sensor error detection
  • Output relay with windows, setpoint and latch functionality
  • Simulation of process value during commissioning / maintenance
  • Fast response time, with simultaneous sensor error detection (PATENTED)
  • All terminals are over-voltage protected, polarity protected and short-circuit protected

What are Frequency to Current Converters and what are Frequency Converters used for?

The process industry requires measurement and control of many process variables. Speed and flow rate are two such variables, where safety and product delivery demand accurate process control.

Sensors used to measure speed often take the form of proximity sensors, which detect a target as it passes by the sensor resulting in a pulse or frequency output proportional to the speed.

To enable these signals to interface with downstream equipment, the pulses or frequencies are often converted to a current or voltage signal. Frequency to current converters such as the PR 4225 and PR 3225 are used for this purpose.