watlow controllers

There are many models and types of Watlow controllers. Some of their common functionalities include controlling temperatures, relative humidity, pH, as well as flow and position of industrial machines and commercial equipment. Explore the integrated controllers with agency-rated safety limits available through leading Watlow distributors, Hi-Watt Inc.

Whether you are looking for a Watlow F4 controller, Watlow EZ-ZONE, Watlow PM PLUS, or perhaps comparing single loop controllers to multi loop controllers we can help.

Watlow Temperature and Process Controllers

Watlow temperature controllers range in size and specifications, from a basic single-loop control to a multi-loop, multi-function device.

Most Watlow temperature and process controllers are designed to control one or two loops. Some can control up to four loops. The EZ-ZONE® RM Rail Mount Controller, however, can control an impressive 152 loops for a factory-wide thermal control solution.

Compare on/off control modes and PID controllers to determine the best way to monitor and alter your thermal system. You can also choose between an LCD, LED or touch screen display. Here are the form factors available to meet your controller requirements:

  • 1/32 DIN panel mount
  • 1/16 DIN panel mount
  • 1/8 DIN panel mount
  • 1/4 DIN panel mount
  • DIN rail mount

While each controller offers unique features, they all offer the same reliable Watlow quality standards. Review each based on the type of panel and thermal system you have and discuss your options with your Watlow distributor.


From the SMOOTH-TOUCH™ keypad to the EZ-LINK™ mobile app capability, the PM PLUS PID and integrated limit controller is designed for intuitive operations. Enjoy backward compatibility as you send information between your PM PLUS and legacy EZ-ZONE PM controllers to avoid communication errors as you update your facility.

The PM PLUS can only control one limit loop. It does so with a streamlined interface to improve user experience, but not at the expense of customizable controls. It comes complete with alarms and error codes to keep you up-to-date with any thermal system issues.


Control up to four PID loops, complete with data logging options and personal profiles, with the F4T. This highly flexible temperature and process controller uses I/O modules that are field removable for convenient scaling or reconfiguration.

The 4.3-inch graphical touch panel is so easy to use that a user manual is almost unnecessary. Monitor up to 24 channels and create up to 14 alarms to remain in control of your system in a range of harsh operating conditions.


As part of the LEGACY SERIES, the PM LEGACY by Watlow uses a universal input and up to two outputs for a flexible mount package. Over- and under-temperature limit controls, or PID controls, and one limit loop capacity make it a simple, straightforward option for basic applications.

Compare 1/16 DIN and 1/32 DIN panel mount package options to determine the best option for your situation. The menu and control features are more simple than other controllers, but the PM LEGACY is a popular option for simple, reliable thermal control.

EZ-ZONE PM Panel Mount Controller

Cut down on thermal loop ownership and system complexity with an EZ-ZONE PM panel mount controller. At its most basic, this controller streamlines your thermal loop controls. When you’re ready to expand the complexity or scale of your process, this scalable controller offers the flexible controls and mount packages you need.

Four alarms and two monitor channels help you track two control loops and one limit loop. Integrate it with a controller to expand the PID controller capabilities in a space-saving design.

EZ-ZONE RM Rail Mount Controller

Manage thermal systems across your entire facility with the EZ-ZONE RM controller. Thanks to the impressive mixing and matching of I/O, you can configure up to 152 control loops and 256 monitor points. This family of controllers includes six module types:

  1. Monitoring and over/under temperature limit controller module
  2. Integrated on-off or PID control
  3. High-density on-off or PID module
  4. Data logging and field communications access module
  5. High-density monitor/scanner module
  6. I/O expansion module

Create up to 24 alarms per module with this impressive rail mount controller. An ambient operating temperature range of 0 to 149 degrees Fahrenheit allows you to install your new controller in a range of commercial and industrial environments.

EZ-ZONE PM Express

Connect your EZ-ZONE PM Express controller with a universal input and either 1/32 or 1/16 DIN output to optimize the performance of your thermal system. This leading PID controller uses straightforward controls and an easily accessible menu for basic operations.

This simplified controller may not have the same wireless connectivity and multiple control loops, but the convenient programming and PC communication keep your system operating with minimal setup and run time. You don’t need a multi-function, complex control device to handle a single, minimal thermal loop in your facility.

Watlow Limit Controllers

Watlow limit controller

Expand your thermal application capabilities with a Watlow limit controller. These controllers are a critical safety feature that helps prevent temperature runaway and over-temperature situations. A Watlow limit controller can be used in multi-loop situations, so they offer a low-cost alternative for a multi-channel facility.

A single loop controller is commonly used for laboratory equipment, furnaces, ovens, boilers, food preparation and more. Choose a double loop limit controller for plastic injection molding equipment, electronics packaging equipment or any other process that requires multi-channel redundant monitoring.

When you put limits on your thermal system, you keep your entire facility safe. Don’t let an over-temperature or temperature runaway situation damage equipment and products or cause injuries. If you’re ready to improve the safety of your thermal system, consider one of these controller products by Watlow:

  • PM LEGACY Panel Mount Controller
  • PM PLUS PID and Integrated Limit Controller
  • SERIES LF Temperature Limit
  • EZ-ZONE PM Express Limit Controller
  • RM Limit Module

Integrated Multi-Function Controllers

Instead of purchasing multiple controllers and other components, a multi-function controller offers integrated convenience. Reduce the space, assembly time, system complexity and design time of your thermal system with one of these Watlow products.

Select a controller that offers the number of loops you need. Consider safety features, panel styles and configuration style to match your industrial or manufacturing process. Consistent features across an entire line of modular products streamline the setup and integration of controllers around your facility.

Multi-function controllers offer both scalable convenience and a streamlined installation process for your existing setup. Compare these integrated multi-function controllers by Watlow to determine the best device to expand your possibilities:

  • PM PLUS PID and Integrated Limit Controller
  • PM LEGACY Panel Mount Controller
  • F4T Temperature and Process Controller
  • RMA PLUS Remote Access Module
  • EZ-ZONE PM Express

Watlow PID Controllers

Some thermal systems require changing temperatures over time. If you need temperature profiling or ramping, then consider a Watlow PID controller. Standard I/O communication options allow easy integration. A durable design works well in demanding environments, including complex process furnaces and environmental chambers.

Program a specific temperature profile and prepare for accurate thermal controls. A Watlow PID controller works well in many environments and is specifically designed to maintain consistent temperatures with exceptional accuracy. Depending on the controller you choose, you can enjoy up to 40 ramp and soak programs and cascade control.