Don’t take chances with low-cost sensors. Some companies have been severely scaling back on sensor quality to meet price targets. Be on the lookout for these telltale signs of poorly engineered or manufactured sensors:
- Varying sensing distance: to drive out costs, some manufacturers are eliminating the final distance calibration step. This means the actual sensing range can vary up to 30% from the specifications.
- Temperature compensation: affecting mostly inductive proximity sensors, this is one of the more technical areas of sensor design. Special circuits and design methods eliminate the large operating distance variation seen with some low-cost sensors.
- Adequate electrical protection: there are numerous methods to protect a sensor’s output circuit, not all are created equal. Many do not take into account overvoltage, overcurrent, short-circuit, reverse supply polarity, mis-wiring, and energy backfeed from the load.
- EMI resistance: influence from electro-magnetic interference (EMI) noise can cause false triggers leading to machine malfunctions. It takes years of experience and testing to make sensors that will operate reliably near motors and drives.
Fortunately, there is an answer to these potential problems: the Global line of sensors offered by a reliable sensor manufacturer with decades of proven experience. These products are not built down to price, but instead are built up to the highest standards in the industry. By utilizing highly automated product lines and funneling usage to fewer part numbers with broader application potential, the Global line is one of the most cost-effective sensors programs available today, and without sacrificing any quality or reliability. Bottom line? You don’t need to sacrifice quality or reliability in order to meet your cost budget. For more information, see the entire Global line here.
Plural of Giz-mo. A noun. Defined as a gadget, one whose name the speaker does not know. Customers call us and ask for this or that “gizmo” all the time! I think we should consider creating a product category simply called “GIZMOS”.
I like to call these things “Enablers” because these devices are very much helping hands that optimize the function of sensors. A sensor of any brand and manufacturer performs only as well as it’s mounted, matching the fixture to the demands of the application at hand. But how often does this happen in a price-driven world? They often end up in below-par mounting that fails with regularity, in both pristine environments as well as in hostile environments. Some examples:
Here’s one example below. These inductive proximity sensors in plastic brackets, showing an exposed coil on one, with corroded mounts on the sensor caused by being beaten to death during parts loading and heat.
With a few “Gizmos” like an application-specific quick change mount, some care in gapping the sensor and guarding the cable/connector system, it could look much different. Check out the examples below.
Photoelectric sensors can suffer the same fate. In this case, a plastic bodied photoelectric sensor, originally used to replace a fiber optic thru beam pair also suffered abuse. With a little extra beefy mounting, these photoelectric sensors can be expected to last a long time without failure.
There are literally hundreds of these mounting “ENABLERS”, off-the-shelf, cost-effective application specific mounts, guards, actuators and entire systems to help protect your sensor investment. All categories of products have these “enabling” accessories for Magnetic Field (air cylinder), Inductive Proximity, Capacitive, Ultrasonic, Connectivity, Linear Transducer and Photoelectric product categories.
Whenever you are providing sensor training or even talking with someone about sensor inevitably, you will be asked about the applications where they are used. Try as you may, it’s sometimes difficult to explain the various ways sensors are used to solve the multitude of applications that exist.
Recently, one of my colleagues brought an interesting article to my attention that I am passing on in this blog post. Check out this article on Sensoring for In-Die Tapping. The author explains the application and provides possible solutions varying from mechanical sensors, photoelectrics, and inductive proximity sensors. In my opinion, it is worth reading to give you another perspective on how to solve one of the many ways to use sensors. Let me know what you think! Did this give you another perspective?
Written by: Jeff Himes
An inductive proximity sensor is a non-contact device that is used to detect a metal target. When power is applied to an inductive proximity sensor the sensor’s coil will generate an oscillating electromagnetic field out of the face of the sensor. This field will vary in shape and size depending on the diameter of the sensor and whether the sensor is a shielded or non-shielded model. For example, a M12 size sensor will generate a smaller electromagnetic field than an M30 size sensor. When the metal target gets close enough to the sensor’s face it begins to penetrate the electromagnetic field. When this happens, eddy currents are generated on the surface of the metal target. As the metal target gets closer to the sensor face – the eddy currents increase – which in turn decrease the amplitude of the electromagnetic field. Once the electromagnetic field’s amplitude is reduced to a certain level – the sensor will activate indicating it has detected the metal target.
This explanation is a little wordy and, as in most cases, a visual demonstration can be of great help. Watch this short video explaining the basic functionality of an inductive proximity sensor.
For more information on inductive proximity sensors, click here.