Introduction
Choosing an industrial sensor can be difficult. How is it possible to select a perfect sensor that meets the requirement or fits the job?
With so many different sensing technologies and devices in the market, this can seem to be a haptic task. It turns out that choosing the proper sensor isn't nearly as tricky as removing all of the bad options. Selecting a sensor requires a series of inquiries to rule out any technology or product that does not meet the job's requirements. The ability to accurately determine a sensor is dependent on knowledge of the application type, product variable, and operating environment conditions. This article will cover the elements to think about while choosing a sensor.
Also see, Difference Between Verilog and Vhdl
Methods to select the Best Sensor
Distance to Target
What is the minimum distance between the sensor and the object? So, if we make a small piece of automation equipment, we want everything to be as close together as feasible. We anticipate the sensor being placed close to the metallic object we wish to detect. An inductive proximity sensor will be the best option in this scenario. Inductive sensors have significant advantages over other sensing technologies, despite their minimal sensing distances (usually 1mm to roughly 50mm). They disregard all materials except metal (e.g., water, oil, non-metallic dust), are physically strong, and are pretty affordable.
Composition of Target
What is the object's material make-up (metallic, non-metallic, solid, liquid, or granular)? Depending on the composition, we get ample options to choose from. Let's pretend the thing is made of metal. We need to ask more questions because inductive, photoelectric, capacitive, and ultrasonic sensors can all detect metallic items.
Control Interface
What kind of controller and switching logic are required? The majority of sensors nowadays are 3-wire DC. Other varieties exist, such as 2-wire DC and 2-wire AC/DC; however, 3-wire DC sensors are required by most control systems. In our situation, a "3-wire PNP NO sensor" is required, which includes three wires (0VDC, output, and +24DC), a PNP-type "sourcing" output (current is sourced from the sensor to the controller), and "normally open" switching logic (the output is "off" when the sensor does not observe the target).
Type of Sensing
Are we looking for process parameters ( temperature, pressure, or flow), the presence of an object, the distance to a goal, or the position of a mechanism? Let's imagine we want to find out if an object is present. That implies we're on the lookout for a proximity sensor (also known as "presence sensors" or "object detection sensors"). There are various sensor technologies that can detect the presence of an object (or absence). In the process, inductive, photoelectric, capacitive, magnetic, and ultrasonic sensors are viable options.
Electrical Connection
What kind of electrical connection do we wish to make? Sensors are commonly provided with three types of electrical connections: a) pre-wired cable with flying leads; b) pre-wired cable with flying leads; and c) b) a pre-wired cable with a molded-on connector (commonly referred to as a "pigtail" connector) c) an integrated quick-disconnect connector The terminal chamber connection type was previously widespread when proximity sensors were employed to replace mechanical limit switches, but it is becoming less common in today's industrial setting.
Accuracy and Precision
Precision and accuracy are not synonymous, even though they are frequently used interchangeably. In contrast, the precise ability of the equipment to notice minute changes is defined as the property or state of being accurate. (A temperature sensor that monitors the usual body temperature at 35.999°C, for example, has excellent precision but low accuracy.) The precision and accuracy of a specific product should be adequate. Excessively much precision can provide the false impression that the value is too precise. Similarly, a high-precision sensor will be costly. Both precision and accuracy can be affected by mistake.
Form Factor
What is the physical form factor most appropriate for our application? It's a tiny space in our case, and there aren't many possibilities for mounting something with many lengths. The threaded tubular housing, the most frequent type of inductive proximity sensor, is thus eliminated. We'll be looking at a low-profile, flat sensor, usually a block style or rectangular.
Special Requirements
Are there any specific conditions for the application? High temperatures (above 80 degrees C), nearby welding activities, or high-pressure washdown procedures are examples of special application requirements. We don't expect anything worse than a bit of machine tool oil splashing around in our machine. This is totally common for inductive sensors to work around; therefore, only an IP67 liquid ingress protection grade is necessary (standard on most good-quality sensors).
Digital lowers costs
It's always preferable to use a sensor with a digital output. Even though digital sensors save money, it's best to avoid using analog field devices because converting analog to digital can cause errors. Sensors with a digital output equivalent are more valuable.
Signal Conditioning
Electrical noise is found everywhere, especially on the factory floor, and it can cause significant reading errors. As a result, protective circuits and signal conditioners can help. Because electronic devices are extremely sensitive to electrostatic charges, we utilize wrist straps, grounded floor mats, heel straps, and air ionizers in the mobile manufacturing industry.
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