4-20mA Signal Isolators

Acromag offers the industry’s best selection of isolators. Dozens of modelsare available to meet your requirements. Select from single, dual, and quad-channel models with AC, DC, or loop-powered operation. Signal splitters deliver dual outputs from a single source. And whether you need a unit that sinks or sources current, Acromag has the right solution for you.

Optical or galvanic isolation eliminate ground loop errors, reduce noise, and block high voltage transient surges. All Acromag isolators will withstand 1500V AC for 60 seconds and provide continuous 250V AC or 354V DC common-mode protection of your precious equipment.

Acromag features solve many tough problems. Our multi-channel modules reduce costs and save space. Models with push-button calibration simplify installation and maintenance tasks. Units with trim pots ship preset for 4-20mA input/output so field calibration is not required.

Watch a signal conditioning guide video for the benefits of different models.

2-Wire Loop-Powered Isolators
Models get power from the 4-20mA output or input loop (sinks or sources current). Typical uses are as a current repeater or to drive resistive loads. 651T and 250T models are ideal for applications that require an isolator with a power supply in series with the output signal. 670T and 270i models are useful when adding and isolating a monitoring instrument to an existing current loop.
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3-Wire DC-Powered Isolators
These models are used to drive resistive loads (sources current). The 4-20mA output signal and DC power share a common lead which is wired directly to the PLC/DCS’s internal ground. Acromag’s 340i model is ideal for applications requiring multiple isolators at a single location where all isolators share the same power supply. PLCs and DCSs usually have 24V DC power available at their input terminals.
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4-Wire AC/DC-powered Isolators
These isolators provide 3-way isolation to separate input, output, and power circuits. They are the safest choice when retrofitting or expanding systems where instrument isolation or the grounding schemes are unknown. These 3-way isolators source current out and do not utilize a separate output power supply. The outputs are designed to drive purely resistive loads.
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