Temperature Switches Rise/Fall Set Points & Hysteresis
Whether using temperature, pressure, or current, the designation of ON RISE or ON FALL is very important. This is due to hysteresis.
Hysteresis The Difference Between Two Points
When a switch changes states, from Open to Closed for example, the point at which it resets to Open, or the original state, will not be exactly at the original point. The difference between those two points is the hysteresis.
Example: temperature switch closes the contact at a set point of 50°F on temperature rise. The switch does not return to open the contacts until 46°F when the temperature falls, the hysteresis is 4°F. If you want that switch to operate at a temperature of 50°F on temperature Rise it would be set at a different point than if you wanted it to operate at 46°F temperature Falling. This is why it is important to understand ON RISE and ON FALL and Hysteresis.
Senasys designs and manufactures snap disc thermostat switches. Senasys switches are UL and CUL Recognized. The majority of our switches are made in the United States and our direct customer service would be happy to help you find the right switch for your application. Senasys snap disc thermostats are single pole, single throw, fixed thermostat which may be used in applications such as industrial and HVAC equipment.
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