Power Driver BPD121

The BPD122 and BPD121 are, dc powered, 4-wire signal-conditioning modules.


The BPD122 and BPD121 are, dc powered, 4-wire signal-conditioning modules.

✔ If wanting a controlled voltage output then use a BPD122

✔ If wanting an isolated input, a controlled current output and the output load is fully independent of the power supply then use a BPD122.

✔ If wanting a controlled current output and one terminal of the load is connected to supply negative then a BPD121 MUST be used.


  • High Power Outputfor applications where an output drive of 100mA(24V) up to 2Adc is required, as is common with hydraulic solenoid drive applications.
  • Signal conversionfrom all commonly used process control signals.
  • Signal inversionfor applications where the output has to decrease forincreasing input (Reverse action).
  • Signal filteringfor fluctuating input signals. The “Ramp option” allowsfor the time constant to be selected by the user.
  • Gain and bias(scaling) adjustments to amplify or zero shift a portion ofthe input signal.

·Dither option. A low level AC signal is superimposed on the output to prevent the output valve or hydraulic solenoid from becoming stuck in applications where the valve is stationary for long periods of time (the amplitude and frequency of the dither signal are specified for the application).

Power supplies for the standard BPD121 include 12Vdc and 24Vdc (other on request). The BPD121 module features a wide range of input and output signals, direct and reverse action, including bipolar input. Input signals range from 0.1V to 100Vdc and 100mA to 1Adc. All units are factory calibrated to customer specification but can be trimmed to final requirements by the SPAN and OFFSET controls (15-turn trimmers) located on front. The output signal level is indicated by a green LED on the front, giving a clear indication of module function, presence of signal and output loop continuity. All units are fitted with a 0.1 second filter. This filter constant can be increased or decreased if required. RF and power transient protection is also standard as with all BASI modules.

Title Type Size
Data sheet application/pdf 708 KB