Frequently Asked Question

A tilt switch is an inclinometer (electronic spirit level sensor) with a switching output at a pre-defined tilt angle. 

This type of sensor is ideal for monitoring the maximum tilt angle of a platform or deck, or detecting when a crane or boom is approaching its unsafe operating limits. When the measured angle exceeds the maximum angle set point, the sensor will switch the output so that the application control unit can take appropriate action (such as activating an alarm, restricting speed/direction of movement, or enabling safe mode). 

A tilt switch is also an ideal replacement for a traditional mercury switch or proximity switch.

DIS Tilt switch has either PNP or NPN output, the connection of the load depends on the output type.

When a switch point is defined, the sensor can switch between conducting and non-conducting by tilting at different positions.

	Definition	PNP	NPN
Operation Zone	Sensor position within ±S Sensor is conducting and can be seen as "On" /switch closed.	The current flows from the Vcc through Sensor(transistor) to the load and finally to the ground. You will measure a voltage about the Vcc.	The current goes from the Vcc through the load to the ground. The output is basically grounded, so you will measure only a few mV, almost 0V.
Critical Zone	Sensor position outside ±S Sensor is non-conducting and can be seen as "Off"/switch is open.	The output pin is grounded, so you will measure almost 0V.	The output pin is connected to the Vcc via the load, so you'll measure a voltage about the same as Vcc.
Load	Resistor 5-10kOhm	Pull-down between Output and GND	Pull-up between Vcc and Output

**In case the sensor is defect, or cable is broken, the sensor is in non-conducting mode, which is "critical".

Take the sensor QG40N-KDXYh-080-ASP-CM-UL as an example.

It has 2 independent PNP outputs with both 80° as the switch point. When the sensor tilts in a position within ­±80°, it is in the operation zone, the sensor is conducting. You can measure a high voltage at the output pin. When the sensor tilts more than ±80°, the sensor enters the critical zone and becomes non-conducting. You will then measure a low voltage instead, because the output is pulled down to the GND. (with external pull-down resistor/relay/load between output and GND)

Following parameters are configurable by the users to prevent intermittent alarms that come and go within a very short time, which can be a problem for the PLC or klaxon.

• Hysteresis:
  By creating a hysteresis, we can prevent sensor constantly switching at the switch point. The actual switch point from critical to operation zone will be ±S', whose value is the programmed switch point S - Hysteresis.
  
  
  E.g. switch point is ±80°, hysteresis is 0.5°, the sensor switches from conducting(operation) to non-conducting(critical) exactly at ±80°, but it switches from non-conducting(critical) back to conducting (operation) at ­±79.5° (80°-0.5°) instead.
  
• Operation to Critical delay
  The switching output changes only when the measured angle is continuously over the switch point S for more than de delay time. If it's a short vibration, the object often returns to its safe position in the operation zone. In this case, the sensor will then not be switched to non-conducting. The timer will be then reset to the delay time and start to monitor again.
  
• Critical to Operation delay
  when the sensor tilts back to the operation zone, the switching output changes only when the measured angle is continuously below the S'(not S) for more than the delay time. Similarly, if it's a short vibration, the sensor moves back to the critical zone immediately, sensor will not be switched and the timer will be reset.

The attached video demonstrates how a QG40N-KDXYh-080-ASP-CM-UL works with following settings:

switch point is ±80° (S=±80°) hysteresis is 2° (S'=±78°) Operation to Critical delay is 0.5s Critical to Operation delay is 1s.

1. Start position 60°, sensor is in the operation zone, therefore it is conducting.
2. Now you move the sensor to 81°, and keep it there for 0.3s, sensor will still be conducting, the timer starts to count, after 0.5s. the sensor will be switched to non-conducting.
3. Now you move the sensor back to 80°, and keep it there for 0.3s, the sensor will remain non conducting, even after 1s, the sensor is still non-conducting because of the hysteresis (the S' is 78°).
4. When you move the sensor to 77° in the operation zone , the sensor will be switched back to conducting 1s after the sensor stays below 78°(S').