Crankshaft runout measurements must be monitored continuously to ensure that they meet tolerance requirements. In addition, the reflective surface of the crankshaft and the high speed of the application can be challenging for sensors to measure reliably.  Keep reading to learn how LM Series laser measurement sensors solve this difficult application.

Application: Crankshaft Monitoring

Engines and motors require many rotating components, such as crankshafts, to function properly. The crankshaft is an important part of any engine and turns the linear movement of the pistons into rotational movement. An uneven crankshaft impairs the balance of the motor and creates heat and vibration which can cause equipment to malfunction. To prevent future mechanical failure, a rigid runout tolerance must be set, and parts must be tested frequently for errors.  This requires a extremely precise measurement solution. In addition, crankshafts are reflective and can be challenging to measure reliably.

Solution: Precise Laser Measurement in Compact Spaces

Monitoring crankshaft runout ensures that the components are properly assembled and meet the manufacturer’s set tolerance level.  Runout measurement is a combined measurement of both the roundness and position of the crankshaft. Measuring within tolerance means that the parts are circular, balanced, and meet the demands of the manufacturer.

The LM series laser sensor is a non-contact measurement solution that can monitor the precise dimensions of runout measurement on a wide range of challenging targets. The extremely precise 0.004 mm resolution and small spot size of the LM can identify very subtle changes in distance that could indicate an uneven crankshaft. With traditional sensors, these distance changes could be missed or lead to false failures. The LM sensor was designed with dynamic power adjustment for consistent readings across shiny surfaces and dark targets, providing less measurement variation and a more reliable inspection.

Each LM laser measurement sensor is capable of a 0.5 ms response speed to quickly identify problems and reduce overall inspection time. As the crankshaft rotates, the LM sensor tracks the measurements reliably and quickly. The LM sensor also features a thermally stable design that resists temperature changes, has superior mounting stability, and performs accurately in difficult environments. This high level of precision is an ideal solution for tight tolerances as it can dependably detect very minor changes in distance.

LM series sensors can be configured via IO-Link, remote input wire, or the optional Remote Sensor Display (RSD). The RSD configuration tool stores sensors settings and uses one display to setup many sensors. The RSD configures sensors up to 20 m away and features a 2-line, 8-character display. This function is ideal for both original equipment manufacturers (OEMs) and end users that install sensors on multiple machines.

Benefits of LM Series Laser Measurement Sensors


The high precision of the LM ensures that parts meet tight tolerances with fewer failures. The 0.004 mm resolution allows the sensor to identify the subtlest changes in distance.  Learn more about laser measurement specifications and how to use them to choose a sensor. 


A fast response time of 0.5 ms and sampling rate of 0.25 ms means the LM sensor provides accurate measurement on quickly rotating parts.


LM sensors feature a thermally stable design that resists temperature changes, as well as enhanced mounting stability, for high accuracy in the toughest environments. The LM has a minimal temperature effect of +/-0.008 mm/°C. This is imperative for high precision applications since even a few degrees of temperature change can cause other sensors’ measurement error to double.