MTT MS3007 Terminal Block Type Distributor (with Isolation)

We had an enquiry from a customer installing a new 2-wire, 4 to 20mA level transmitter in a remote tank farm. Their control room power supply was already fully loaded, and they wanted to know if there is a way to power the new transmitter without running another dedicated power feed all the way out to the tank.

This looks simple, but powering a 2-wire transmitter is not just a matter of connecting any 24V DC source. The loop needs to tolerate the transmitter’s own voltage drop, and if the supply feeding your transmitter shares a ground with other equipment in the panel, you risk exactly the ground loop and noise problems that plague long field cable runs. From our experience, this catches out a lot of sites where instruments were added over the years without a clean, single, isolated supply per loop.

For this, we would normally recommend the MTT MS3007, a terminal block type distributor with isolation. It supplies loop power directly to a 2-wire, 4 to 20mA transmitter and, at the same time, re-issues that signal as a fully isolated DC output for your PLC or DCS. Because the transmitter power comes from the module itself, and because input, output, and power are all electrically isolated, ground loops and noise coupling are eliminated at the source. It is equally useful as a straightforward isolator — you don’t need to power a transmitter to use it that way. Front-accessible zero and span trimmers make on-site calibration fast, and it mounts directly on the DIN rail inside the panel or junction box.

Before we quote, we would normally check whether you need the loop-power function or just isolation, and the output signal type your PLC or DCS card is set up to read. Hope this helps — send us your loop details and we can confirm the right model.