TLSA

Triple Output 4-20 mA Current Loop Splitter / Retransmitter

Navigation: Home > Transmitters, 4-20 mA

Key Features

Device removal or failure in any output loop will not affect other loops.
Powers 2-wire transmitters at 20 Vdc.
Independent zero and span controls for each output loop.
Mounts on 35 mm DIN rail.
Only 22.5 mm (0.9") wide.
Powered by 95-264 Vac (Model TLSA-1) or 11-30 Vdc (Model TLSA-2).
Splits one 4-20 mA input loop into three independently scalable 4-20 mA output loops.
Simple to install and commission.
Replaced by Model QLS Quad Loop Splitter for new applications.

Why a Loop Splitter is Needed

In many industrial systems, the same 4-20 mA signal from a transmitter is sent to multiple devices in series, such as panel meters, chart recorders and PLCs, as shown below. When any device in the loop is removed, fails, or suffers a wiring fault, all other devices will then also lose their 4-20 mA signal.

4-20 mA process loop with three devices in series in loop.

The TLSA Loop Splitter Solution

Model TLSA Loop Splitter / Retransmitter solves the problem by sourcing three independent 4-20 mA outputs from a single 4-20 mA input. This allows three separate remote devices to be independently fed from one signal. If any output device is removed or fails, the other devices will continue to operate properly. Each output loop has its own zero and span controls to allow individual scaling.

A built-in regulated +20V excitation supply can power a two-wire transmitter on the the input side and sources the three 4-20 mA outputs. Multiple devices can be connected in series in each output loop, provided that the total resistance per loop is less than 600 Ohms and output devices do not share the same ground.

4-20 mA process loop with three devices in parallel in loop, made possible by Model TLS loop splitter / retransmitter.

Grounding Considerations

With Model TLSA, the outputs must be electrically floating and cannot share the same ground. This is because the four grounds of the input and outputs are different and are each referenced by varying amounts to the high side of the +20V excitation supply.

Use Model QLS Quad Loop Splitter if the outputs must share the same ground. Model QLS offers all capabilities of Model TLSA and more, and is less expensive. It can source up to four (4) independently adjustable 4-20 mA outputs from a single input. The outputs can share a common ground. The input and outputs are mutually isolated to ±10V by means of active circuitry to accommodate differences in local grounds with normal industrial grounding practices.

Designed for system use. Optional plug-in boards for communications and control include Ethernet and other serial communication boards, dual or quad relay boards, and anisolated analog output board. Laureates may be powered from 85-264 Vac or optionally from 12-32 Vac or 10-48 Vdc. The display is available with red or green LEDs. The 1/8 DIN case meets NEMA 4X (IP65) specifications from the front when panel mounted. Any setup functions and front panel keys can be locked out for simplified usage and security. All power and signal connections are via UL / VDE / CSA rated screw clamp plugs.

Multiple relay operating modes are selectable in software. One of these is band deviation setpoint operation, where a deviation limit (such as 50 counts) is set up around both sides of the setpoint. The relay closes (or opens) when the reading falls within the deviation band, and opens (or closes) when the reading falls outside of this band. This mode sets up a passband around the setpoint and is often used for component testing.

TLSA Principle of Operation