Selecting the Right Temperature Controller: Single Loop or Multi-Loop?

An industrial temperature controller measures the temperature of a machine or fluid, and then automatically compares the temperature value to a set (desired) value. If a temperature controller detects a deviation between the real temperature and the desired temperature, the controller adjusts heating or cooling outputs to restore to an optimal temperature. There are two major types of controllers: multi-loop and single loop controllers.

In this article, we’ll cover each type and how to select the right one based on your application.

Single Loop Controller

Single loop controllers are widely used in plastics manufacturing and packaging, and other demanding applications. Typically front panel-mounted, single loop controllers immediately send a digital signal when temperatures exceed or fall below a desired temperature. 

Cost-effective and simple to integrate with other equipment, single loop controllers are designed to specifically control one variable. In some cases, a single loop controller can serve as a backup or alternative to a distributed control system.

Multi-Loop Controller

Usually rear-mounted on a panel, a multi-loop controller monitors multiple areas simultaneously to prevent destabilization of temperature conditions. Depending on the temperature needs of production operations, multi-loop controllers can be programmed to monitor areas independently or collectively. Additionally, some multi-loop controllers offer options like control and analysis of humidity, viscosity, and pressure.

Single Versus Multi-Loop Controllers

With the ability to stabilize multiple variables, multi-loop temperature controllers make excellent substitutes for programmable logic controllers (PLC), when a PLC is not necessarily needed. Multi-loop controllers are also more affordable than PLCs. They are available as a mobile or portable device, and include outputs, control options, and other features relevant to a particular application.

Single loop controllers are more applicable for small- to medium-sized machines and processes that monitor one temperature variable. 

Selecting the right temperature controller essentially boils down to whether a machine or process demands precise control of one variable or control of multiple variables.

Get Help From Hi-Watt Today

Serving Michigan, Hi-Watt is a trusted distributor of Watlow single loop and multi-loop controllers. We’ve been providing industrial heating solutions to clients in a wide range of manufacturing sectors for over four decades. 

If you’re not sure whether you need a multi-loop or single loop controller, we’re happy to help. Fill out our online form, and a member of our team will be in touch with you shortly.