The TransPak series two-wire transmitters are compact, rugged units that receive signals and direct sensor inputs, and operate from power derived from the output signal loop. The TransPak series provides a complete line of direct interface and conditioning modules for use with temperature and other process parameters. TransPak transmitters also accept a wide range of other electrical DC and AC voltage and current inputs.

Two-Wire Transmitters
Two-wire transmitters offer several major advantages over conventional four-wire types, which require two wires for the output signal and two more for the power supply, typically 120VAC. In applications where the process sensor may be located up to several thousand feet from the instrument being operated, two-wire transmitters are advantageous because their current output signals do not attenuate or degrade over distance as do voltage signals. Additionally there can be significant savings in wiring cost since only two wires are needed for the power and signal when compared to the four-wire type. They are ideal when no isolation is required between the output signal and power.

Intrinsic Safety
Because two-wire transmitters are powered from the low-level 4-20mA or 10-50mA output current signals, no additional power has to be supplied to the remote transmitting location. This eliminates an associated problem of having to provide and maintain long runs of expensive wiring, and adds the benefit of being able to comply with safety requirements restricting the use of high-voltage (120VAC) in hazardous locations.

Due to their low energy consumption and storage, two-wire transmitters are the only types of transmitters considered for intrinsically safe applications. Many of Action’s TransPaks are Canadian Standards Association (CSA) and CENELEC approved for intrinsically safe operation in hazardous - even explosive - environments when installed in accordance with the manufacturer’s drawings.