In the automation world, many different types of positioning systems are available. Whether mechanical, optical, magnetic, ultrasonic, inductive, camera-based systems, or a combination of technologies, determining which of these is effective for your positioning application is critical to the success of your automated processes.
Proximity sensors and encoders can have NAMUR output
NAMUR is a type of sensor output that gives an on or off indication. There are different reasons why you may need a NAMUR sensor. I will go through some of them here.
Instead of laser displacement sensors
When you’re looking for a solution to a problem or application, there may be a few different ways of solving it. How do you decide which one to use? You usually try to find reasons for why you would use one device over another. I will give you 5 reasons why I would choose a rotary encoder over laser displacement sensors.
Choosing the correct industrial encoder is easy when you know the answers!
There are many reasons why you may need a rotary encoder, but what questions should you ask to determine which one is the most appropriate? Here are seven questions that can help you make the best decision:
Cable pulls enable rotary encoders to measure linear motion. A cable is wrapped around a spring-loaded measuring drum that turns the encoder's shaft when the cable is pulled in a straight line by the application. Each revolution of the encoder represents a linear movement of the cable equal to the circumference of the measuring drum.
Industries and applications that commonly use this method of measurement include:
- Mobile equipment: cranes, drilling machines, and excavators
- Material handling: gates, multilevel shelving rack systems, theater stages, forklifts
- Automotive: scissor lifts, multilevel conveyors
These cable-based length-measuring systems have been proven to be very robust, reliable, and accurate at lengths up to 50 meters.
Cable pulls are generally equipped with a mounting face for servo or clamping flange with a coupling mechanism that allows connection to rotary encoders for linear position tracking and feedback. The encoders convert the number of drum revolutions, which is proportional to the measured length, into a digital measuring signal.
The digital measurement signals of position encoders can be output as incremental measurement pulses, but more commonly absolute encoders are used. Absolute encoders are typically available with CANopen, PROFIBUS, EtherNet I/P, DeviceNet, and PROFINET interfaces.
Encoders and cable pulls are often available separately and can be combined for particular applications. Always make sure that the mounting flange styles and shaft sizes for both the cable pull and encoder match.
Topics: Rotary Encoders
When it comes to incremental rotary encoders, knowing the differences between the available output types can help you choose the best solution for your particular situation.
The output signals of incremental rotary encoders incorporate two channels to indicate rotation of the encoder shaft plus a zero marker pulse channel. These A and B channels (quadrature) are defined as pulses per revolution (ppr) and define the smallest rotational angular position of the shaft that can be resolved. Since these signals are in quadrature mode, 90 degree phase shift relative to each other, they can also be used to determine the direction of the encoder shaft and multiplied to provide increased resolution. The zero marker pulse channel, Z or 0, is a once-per-revolution pulse that can be used to indicate a zero or home position relative to a single revolution of the encoder.