The faceplate on these controllers is sealed to meet NEMA 4X and IP66 for protection in washdown environments with splashing water, corrosive liquid, and dust. The rear case meets IP20, which prevents objects about the size of a finger from coming into contact with a live circuit.

Because they have proportional-integral-derivative (PID) software, these controllers are ideal for turning heating equipment on and off in systems with rapid, unpredictable, and complex temperature changes. They help you achieve precise and stable temperature control with fuzzy logic that learns system behavior and automatically compensates for changes. Use the autotuning function to cycle and identify the ideal PID variables for your system to achieve the most precise control. These controllers read temperature with a highly sensitive thermocouple probe (sold separately) in critical process applications. All fit into instrument panels with DIN cutouts. Use the keypad to adjust the actuation point, reset point, and other settings.

Controllers with automatic reset switch off and on again automatically as the temperature fluctuates. Controllers with automatic/manual reset give you the choice to have machines turn back on either automatically when the temperature fluctuates, or you can manually reset their switch. When set to manual they shut down your machine when it gets too hot to protect equipment and personnel. They won’t turn the machine back on until you reset their switch. They have a second output to actuate an alarm or another simple device.

Mechanical relay outputs actuate circuits directly. Single pole, single throw (SPST) relays turn one circuit from off to on (normally open). Single pole, double throw (SPDT) relays can be set to turn the circuit from off to on (normally open) or from on to off (normally closed).

Solid state relay outputs send a pulse signal to directly control an external solid-state relay (not included). They have a longer service life than mechanical and signal relays. Use them for more precise and rapid control switching than mechanical relays.

Analog signal outputs send 4-20 mA current to actuate equipment on a current loop. They are typically used with SRC (silicon controlled rectifier) power controllers (not included) for some of the highest precision control.

DIN-rail/surface-mount adapters (sold separately) mount 1/16 DIN controllers to a surface.

DIN cutout adapters (sold separately) convert larger cutouts to fit 1/16 DIN controllers.

For technical drawings and 3-D models, click on a part number.

Switch heaters on or off when your process reaches a certain temperature. Both these controllers and your heater will be powered by the same wall outlet. Place the probe into your process, plug the controller into an outlet, and plug your heater into the socket on the back of the controller’s plug. These simple temperature controllers deliver either full power or no power. They’re best used in systems where temperatures change slowly and you don’t need precise control.

IP20 and NEMA 1 rated controllers are best for indoor use. They keep dirt out and will stop objects about the size of a finger from coming into contact with a live circuit.

For technical drawings and 3-D models, click on a part number.

To protect equipment and personnel, these controllers shut down your machine when it gets too hot. Reset them manually to turn your machine on again. They're often used as a fail-safe system and for triggering alarms.

Set the actuation point and adjust other settings with the keypad. To read the temperature, these controllers use a highly sensitive thermocouple probe (sold separately). They have one or two mechanical relays that actuate circuits directly. Mount them into instrumentation panels with DIN cutouts.

Controllers that are SPDT (single pole, double throw) can turn one circuit from off to on (normally open) or on to off (normally closed).

Controllers that are SPST-NO (single pole, single throw) can turn one circuit from off to on (normally open).

Remote-reset controllers are best for hard-to-reach locations. To operate, you’ll need to wire the remote reset input terminals, and the sensor must be below the set temperature.

To mount 1/16 DIN controllers to a surface or DIN rail, add DIN-rail/surface-mount adapters. To convert larger cutouts to fit 1/16 DIN controllers, add DIN cutout adapters.

Keep electronics in your enclosure from getting too hot or cold with these thermostats that control two devices at once. Clip them to a DIN rail to install.

Nonadjustable thermostats prevent tampering and accidental changes. Adjustable thermostats allow you to set custom temperatures.

Heating and cooling thermostats control heaters and fans or air conditioners. Thermostats with one actuation point, also known as changeover thermostats, switch between heating and cooling so one device is always running. When the temperature in your enclosure gets hotter than the temperature you set, the thermostat will turn on your fan or air conditioner. It goes back to heating once the temperature is reduced by the temperature difference. So for a thermostat with a temperature difference of 9° F, setting it at 60° F means it will heat the enclosure until it reaches 60° F, switch to cooling until it reaches 51° F, and then switch back to heating.

Heating and cooling thermostats with two actuation points control two devices independently. When your enclosure temperature is within the set range, neither device is powered, so they’re more efficient than changeover thermostats. For each device, temperature setting is the high end of the temperature range, and temperature difference is the size of the range. For a thermostat with temperature settings of 59° and 95° F and an 18° F temperature difference, the heater will switch on when your enclosure is colder than 41° F and turn off when it reaches 59° F. The fan or other cooling device will switch on when the temperature goes above 95° F and turn off once the enclosure cools to 77° F.

Cooling thermostats regulate two cooling devices, such as a fan and an air conditioner, for two-stage cooling. Use only one device for cooling in mild temperatures or both for extreme heat. These thermostats switch your equipment on when the enclosure is hotter than the temperature setting. Once the temperature is reduced by the temperature difference, it will switch off. For example, a thermostat set at 77° F for a fan and 140° F for an air conditioner will power both devices when the enclosure is over 140° F. With a temperature difference of 18° F, the air conditioner will switch off when the temperature goes below 122° F. The fan will run until the temperature reaches 59° F, and switch back on if it heats up to 77° F or hotter.

All thermostats meet IP20, which means they’re designed so fingers can’t fit inside and get shocked. They also meet UL 94 V-0, so they self-extinguish within 10 seconds if they catch on fire and won’t spread the fire by dripping. Thermostats that are CE marked or VDE certified meet European safety standards. UL Recognized Component and C-UL Recognized Component thermostats also meet American and Canadian safety standards.