4-20mA Signal Isolators

Acromag offers the industry’s best selection of 4-20mA signal isolators. 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.

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    TT236: Current / milliVolt Input Two-Wire Transmitter

    • Multi-range ±20mA or ±500mV input
    • 4-20mA ouput (sink/source)
    • 12-32 V DC loop/local power
    The TT236 model is a space-saving two-wire transmitter that isolates and converts a DC current or low voltage input to a proportional 4-20mA control signal. A single unit supports both voltage and current input for extra flexibility. Power is received from the output loop current or a DC supply when using a three-wire connection. Click here to watch a short AcroMaggie video highlighting the TT230 Series.
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    671T, 672T, 674T: Multi-Channel, Two-Wire Isolators

    • DC current input
    • Single, dual, or quad I/O loop-powered isolators
    These units receive 4-20mA process current inputs and provide isolated 4-20mA output signals. Power is derived from the input signal current. Each channel operates independently and is isolated from the others to prevent interaction between channels.
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4-20mA Signal Isolators Continued

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Signal Isolators For Signal Conditioning

As your I/O experts, Acromag is here to help! Below are three of our most popular application notes and whitepapers related to our signal isolators. Many times choosing the right isolator requires more than just comparing the number of channels and the cost per point. Find more application notes, white papers and support here: https://www.acromag.com/support/

Top 3 Ethernet Industrial Isolation Papers:

Some signal isolators are ideal for applications that require an isolator with a power supply in series with the output signal. Power is obtained from the output loop. The isolator must control current draw from the power supply in the output loop which is the 4-20mA signal. Since output and power share the same two wires, this type of isolator can be placed anywhere between the field sensing device and the PLC/DCS or monitoring device. Usually, the isolator is located close to the field device. Since both the input and output signal are 4-20mA, location of the device is not critical.

Other signal isolators are useful when adding and isolating a monitoring instrument to an existing current loop. When adding a field device such as a recorder or display, no additional power source is required for the added loop or for the isolator. The isolator's output is powered by the input loop power and drives passive loads only.