APG Float Switches

APG Float Switches | Descriptions

APG's story begins with a Utah State University graduate using his engineering skills to make a difference in the lives of farmers. Cordell Lundahl designed an ultrasonic sensor and control system that could guide farm machinery around the uncut edge of a field. A farmer, riding in a second machine, could effectively make two cuts with one pass leaving more time for all the other unending farm chores. Fast-forward 40 years, and APG now offers a full line of level sensors and switches, pressure transducers, and data management tools to help everyone from farmers to chemists, and waste managers to food and beverage producers control their processes and inventories.

Float switches work much like a standard light switch, they open and close contacts to control whether or not signal current can pass through. They are either Normally Closed, meaning current is flowing, or Normally Open, meaning current is not flowing. The “Normal” state is when the float switch is down, resting on it’s cable or float stop.

In other words, float switches consider an empty state normal (no liquid to lift the float). A Normally Closed float switch in an empty tank would have current flowing through it, activating whatever process it is supposed to - such as turning on a pump, or sounding an alarm. A Normally Open float switch, on the other hand, would break the current in an empty tank, and would not close, or activate, until the tank was full enough to lift the float.

Float Switches

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