The Difference Between a Limit Controller and a Process Controller

When it comes to kiln temperature controllers, there are two broad categories: process controllers and limit controllers. So, what’s the difference?

Process Controllers vs Limit Controllers: Function & Use Cases

If you use an at home kiln or a studio kiln, chances are you’re more familiar with a process controller. Process controllers, also known as programmable digital controllers, automatically adjust kiln temperature to execute kiln firing schedules with very little user involvement.

Limit controllers, on the other hand, are currently more commonly used with ICS control systems, industrial kilns, and manual kilns. Also known as high limit or safety limit controllers, limit controllers monitor kiln temperature and ensure that the kiln automatically shuts off if the kiln exceeds a specified temperature.

Process controllers execute process; limit controllers enforce limits. Process controllers are a primary kiln control method. Limit controllers, while not usually suitable to be the primary control method, are an important part of kiln safety and can protect you, your equipment, and your property in the case of relay or system failure.

If I Already Have a Process Controller Why Would I Need a Limit Controller?

If you’re reading this article and you already have a process controller, you might be asking: Why would I need a limit controller?

The answer? Safety.

Even though advanced kiln controllers, such as TAP and TAP II, provide max temperature safety shutoff in case of relay failure, redundancy is the key to safety. Safety limit controllers such as TAP Monitor add an additional layer of safety. When installed and wired to a redundant safety relay, TAP Monitor will automatically shut off your kiln if it exceeds a specified temperature – even if your primary relay fails.

Benefits of TAP Monitor Limit Controller

TAP Monitor is an advanced, user-friendly kiln limit controller and pyrometric device that can be paired with any manual or automatic kiln controller to provide safety shutoff and remote temperature monitoring.

Available as a plug-and-play standalone pyrometer limit controller or as a set of configurable components for DIY installs and oven builds, TAP Monitor gives ceramicists, potters, glass artists, and bladesmiths the ability to:

• Wire TAP Monitor to a safety relay to provide redundant safety shutoff.
• Precisely monitor the temperature of their kiln, oven, or forge via the TAP Kiln Control Mobile App.
• View digital pyrometric readouts from any manually controlled kiln, including remote readouts via TAP Kiln Control Mobile when TAP Monitor is connected to a local network.
• Easily add precise, real-time digital temperature readings to their manual kiln or oven.
• Pair TAP Monitor with their existing automatically or manually controlled kiln for remote monitoring.