Electricity + Control February 2019

SENSORS, SWITCHES + TRANSDUCERS

Questions to ask when choosing a vision solution

Vision sensors and smart cameras are of the most accessible vi- sion technologies for those just getting started with implementing vision solutions in their manufacturing processes. However, vision can be challenging and many users find it difficult to know where to start. BrandonTopham of Turck Banner suggests four questions that will help you evaluate your application requirements before making a decision. 1.What is the speed of your application? It is important to verify that the vision solution is suited to the speed of your application. The more conditions that need to be inspected, the longer the inspections will take. 2.What is the distance from object to sensor? How far away from the objects will the sensor be mounted? A vi- sion sensor should typically be mounted less than 12 inches away from the target. For further distances, a higher end system may be required. 3.What size objects are you inspecting? The object(s) must fit within the viewing window of the vision sensor. Since vision sensors have a more limited field of view than more expensive vision solutions, they work best for small parts, or assemblies with small quantities of parts. If a wider field of view is needed, a smart camera may be a better option—offer- ing more functionality while still being easy to commission and use. 4.What are you looking for? This is the question with which many people struggle. You know you are looking for a ‘good’ condition, but what counts as good? What are your true pass/fail requirements? For this, you need to evaluate your tolerance for less than perfect parts. One way to do this is to find your ‘best bad’ part and your ‘worst good’ part and set the tolerances for the sensor at both ends of the spectrum. Setting tolerances is essential for any vi- sion application and will help ensure you are not wasting parts and material by rejecting parts that should be considered passable— or allowing parts through that should have been rejected.

Next steps After answering these questions, the next step is to try out a solution. Every vision application is unique, and it is best to try out the device in real-world conditions to make sure it works for your application. Partner with a manufacturer that offers both vision sensors and smart cameras, which makes it simpler to upgrade if needed. A vision sensor is a self-contained device that includes vision lighting, lens, and camera in a single compact unit that simplifies implementation. Vision sensors are available with a variety of lens and lighting options to match numerous applications using one simple device. Smart camera A smart camera is a vision system that can be used to solve a broad range of applications and provide advanced capabilities, such as feature measurement and flaw analysis. Smart cameras generally require a PC for programming. They offer more function- ality than a vision sensor, while still being a versatile, easy-to-use vision solution. Enquiries: BrandonTopham,Turck Banner. Email: brandon. topham@turckbanner.co.za Definitions Vision sensor

Integrative pressure measurement in the smallest of spaces

With a diameter of 19 mm and a height starting from 17 mm (depending on the process connection), the sensor mod- ule can be integrated into a wide variety of products and systems. The custom-fit specification is supported by the selec- tion of analogue and digital output signals. The version with digital I²C signal features very low power consumption and a fast response time (3 ms). It is therefore ideal for applications with battery operation. In addition, a tempera-

WIKA has expanded its portfolio for OEM applications with the very compact MPR-1 piezo sensor module with stand- ardised output signal.

ture value can be output via the I²C signal. The model MPR-1 is available, as standard, with gauge and absolute pres- sure measuring ranges (from 0 ... 0.4 bar to 0 ... 25 bar) as well as vacuum measur- ing ranges. It measures with an accuracy of ≤ ±0.5 % of the span. On request, a higher accuracy and other pressure rang- es are possible. Enquiries:WIKA Instruments (Pty) Ltd.

Tel: +27 (0)11 621 0000 or Email: sales.za@wika.com

28 Electricity + Control

FEBRUARY 2019