Applications involving precision motion control typically use electric servo systems for speed and accuracy, which electric servo systems can handle very well. However, in some cases, the accuracy delivered may be more than needed, and the cost of the electric servo may break the design budget. Fortunately, leading manufacturers of pneumatic valves are developing new high-speed control valves and sophisticated electronic controllers that allow incredible speed, precision, and variable load control to be delivered from a pneumatic cylinder. Most importantly, the overall cost of these servopneumatic systems can compare quite favorably with all-electric systems.
Pneumatic cylinders are used in many applications as prime movers in machinery, material handling, assembly, robotics, medical, and the list could go on. One of the challenges facing OEM’s integrators and end users is to detect reliably whether the cylinder has been fully extended or retracted before allowing machine movement. Solutions include the use of inductive sensors with some sort of target and internally mounted magnet (by the cylinder manufacturer) on the cylinder piston. In my previous blog, I discussed the two primary magnets, axially and radially magnetized magnets, used by cylinder manufacturers. Now, we will review one of the most commonly used magnetic field sensors to detect extension and retraction of the cylinder…the well-known reed switch.
Have you ever made the statement, “If I had it to do over again, I would’ve done it differently”? Well, here’s your chance. Many companies are migrating from DeviceNet to EtherNet/IP and now you can take this opportunity to do it differently. As a former Allen Bradley Instructor, I have seen enough bad DeviceNet installs to write a book. Here are six topics to consider in your new EtherNet/IP installations:
Linear position sensors are available with a variety of different output signal types to suit various application requirements and control architectures. Let’s take a look at three of the most common output signal types for linear position sensors; 1) analog, 2) time-based digital, and 3) serial digital, and discuss some of the pros and cons of each.
Written by: Jeff Himes
In almost all inductive proximity sensor applications the housing design and mounting method of the sensor need to be taken into consideration. Sensor housing designs have historically been described as shielded (sometimes called flush) or non-shielded (sometimes called non-flush). In reality the terms shielded and flush have different meanings just as non-shielded and non-flush have different meanings. By using these terms interchangeably some confusion is typically created. Additionally, a new term of “quasi-flush” has entered the market. Let’s take a closer look at these terms and what they really mean. Continue reading “Flush or Non-Flush, Looks Can Be Deceiving”
Written by: Bjoern Schaefer
In this new series we will write about different aspects of capacitive sensors in today’s factory automation world. Capacitive sensors found their place in certain industries and applications as effective problem solvers for specific tasks such as plastic pellet detection devices in injection molding machines and liquid level monitors in the semiconductor industry.
Industrial networks are nothing new; ASi, CANbus, DeviceNet, Profibus (to name a few) have all been around for years. Designers of production equipment use networks for a variety of reasons: simplified machine mount I/O, motor starters, valve bank control, etc. Each network has a limited number of devices that can be connected and each device is designated a node address or IP address. IO-Link takes a standard network and expands it beyond its current capacity through flexibility and expansion.
How would you like to improve your electric servo system using an alternative type of position feedback? Direct Load Monitoring has these 4 key advantages.
It’s 3:00 AM and your machine has come to a screeching halt because, according to your PLC, the cylinder that holds a part in place is neither extended nor retracted. After looking at the cylinder, you see it is extended just as it should be however; the cylinder-mounted sensor is not detecting the magnet. No problem, you have another magnetic field sensor that will fit but it does not work either, so what is the problem? Another bad sensor? Maybe not, it could be the sensor and the magnet is incompatible.
Many sensors used in industrial automation applications – linear position sensors and long-range distance sensors being two of the most common types – produce an analog output that is representative of the position or distance being measured.