Limit controllers are typically added to thermal applications to monitor an over-temperature condition as a safety precaution. Limit controllers provide 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.
ETR-9040 1/16 DIN Microprocessor Based Limit Control
The ETR-9040 Limit Control protects equipment, materials and personnel from over-temperature process conditions. A true back-up system can be put in place when this control is used with a dedicated sensor and contactor. Universal Input allows the ETR-9040 to be used in many temperature, pressure, flow and other control applications. An optional port provides additional functions such as a programmable alarm, RS-485 communications, DC power supply, limit annunciator, or event input. The 18 bit A/D converter and 5 per second sample rate reacts quickly to protect fast changing processes. The large display can be set up to view the Process Value (PV), Set Point Value (SV), or SAFE. A main output Form C relay can be configured as a High Limit, Low Limit or High and Low Limit. The ETR-9040 should be protecting your process because it's easy to use, versatile and extremely accurate.
SD Limit Control
The SERIES SD family of limit controllers has been designed with the same microprocessor-based technology as the SERIES SD PID family of temperature controllers. The limits come with the FM (Factory Mutual) agency approval -- the industry's most recognized designation for insurance concerns.
Series 97 Limit Control
Watlow's Series 97 is a microprocessor-based controller with a single input, second auxiliary input and four outputs. Input 1 is used to measure temperature from a sensor. Input 2 can be utilized as a remote reset switch or a hardware lockout switch. With up to four outputs, the controller is versatile in handling applications that require a high/low limit, alarms, retransmit and communications. The control is so user friendly it can be set up to display safety and limit messages created by the end user to meet the exact application need.
Series L Limit Control
The variable options, SERIES LV (limit), include an operator interface for viewing and selecting the set point. A red, four-character seven segment LED displays the set point with a push to show process option. The set point selection is made with a continuous turn rotary encoder. Operating range temperature values are customer definable in the product configuration part number.
16L Limit Control
The 16L FM Limit control offers universal input (10 thermocouple types, 4 RTD types, voltage, and current), single or dual set point, Peak / Valley indication, field configurable display, standard remote reset capability, and illuminated keys.
Options for the 16L include Process Output Retransmission (Voltage or Current), RS-232 Serial Communication, or RS-485 Serial Communication.
Designed and built in the USA, the 16L family of controls offers the highest levels of features, function, and quality available today.