The Watlow SD Series limit controller has been designed with the same microprocessor-based technology as the Watlow SD Series PID temperature controller. The limits come with the FM (Factory Mutual) agency approval - the industry's most recognized designation for insurance concerns.
Watlow SD Series limit controllers are typically added to thermal applications to monitor an over-temperature condition as a safety precaution. The Watlow SD Series limit controller provides a redundant safety assurance to guard against instances where a high temperature runaway condition could result from a shorted input sensor, or from an output device that fails in a closed position.
Watlow SD Series limit controllers are often required in applications where thermal runaway could result in costly operator safety concerns, product scrap, damage to capital equipment, or a fire hazard.