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From actionio.com
One of the more common requests that Action receives these days is the need to "isolate" a 4-wire field transmitter from a PLC or DCS that supplies loop power. This is not "isolation" in the traditional sense of eliminating ground loops. In this case, the problem is that there are too many devices powering the 4-20mA loop. By definition, a 4-wire transmitter supplies the required loop voltage, or "sources" the current. I have also recently heard this called an "active output". The problem arises when the receiving device also tries to put voltage on the loop. This is handy when the field device is a 2-wire transmitter ("current sinking" or "passive"). Products & Services
Eddy current proximity sensors and switches detect the proximity or presence of a target by sensing the magnetic fields generated by a reference coil.
Ultrasonic proximity sensors use reflected or transmitted ultrasonic waves to detect the presence or absence of a target component.
Capacitive proximity sensors detect the presence or proximity of a target using capacitive technology.
IC phase-locked loops (PLL) are closed-loop frequency controls that are based on the phase difference between the input signal and the output signal of a controlled oscillator.
Vibration transmitters provide electrical outputs that are proportional to vibration inputs.
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Topics of Interest
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