Some problems with the level switch?
Thread Content
2. Level switch: Output: relay, normally closed (NC) contact; Switch type: normally closed contact; Electrical interface: 1/2\" NPT. What is the principle of operation of a level switch, and what is its structure?
There are various principles behind level switches; tuning forks, capacitors, radio frequency floats, and more can all be used. I understand that a dry contact can operate without any power supply from the system; so, it’s possible that a mechanical float switch could also do the same
It is a float-type level switch. What is its principle and structure like? Who can upload a picture for us to take a look? Thank you.
The principle of the float is similar to that of the float in household toilets: it is a ball that moves along with the liquid level, and when it reaches a certain position, it triggers a switch, thereby enabling the circuit to be turned on or off
The dry contact of the level switch functions similar to the normally open contacts of a contactor; it requires an external power supply and can be connected directly to the digital input card in the DCS. The principle behind the level switch is that a float moves a magnet, and this magnet in turn causes the switch to close or open.
A level switch simply sets an alarm value; it only responds to changes in the liquid level once that value is reached. The set point of a conventional level switch is usually slightly higher than that of a level gauge; this depends on the installation height and working principle of the level switch. The level gauge sets an alarm value before the level switch triggers an alarm, allowing for early detection of changes in liquid level and enabling appropriate action in case of high liquid levels. If a liquid level switch is to be used in interlock mechanisms when an alarm is triggered, the most common type is the fork-type liquid level switch; more details can be found at http://bbs.hcbbs.com/viewthread.php?tid=354258
The float-type type uses a reed switch to complete the circuit; this was the most commonly used method in the past.
Float-type level switches come in two types: those with a torsion rod and those with a spring; in China, the torsion rod type is generally used. The principle of the switching section has been explained above; currently, a three-magnet structure is generally used