Scalable Vision System

VEA developed IVIS, which encompasses several features in a single scalable system, from vision sensors to complex systems. Equipped with a single powerful configuration tool and modular expandability, it cuts down on installation costs and time. And it is a completely Italian idea

by Noemi Sala

In the manufacturing sector, especially in segments linked to the automotive industry, a considerable increase was recorded in the request for quality controls to be carried out automatically directly on the production line. For many industrial segments, the need to ensure that all products are compliant to specifications is increasingly pressing; statistical sample controls are therefore no longer sufficient. Vision systems are a valid solution for these issues, but often enough clients complain about low reliability, especially when the reliability requested is in terms of parts per million (PPM). The reasons are many and vary from one case to another, but the experience accrued over the years allowed VEA, a manufacturer of vision systems, to identify a few basic rules which reduce installation risks and increase the reliability of the applications.

Some requirements become evident only after installation
Artificial vision is a ratter complex field, and in some projects it is not possible to know beforehand all the properties which the system must have, because often some requirements become evident only after installation. Clients’ initial requirements may vary during installation or they may be a divergence between the requests of the quality control and production departments; in other words, an unforeseen requirement may generate a number of faulty items which production may consider too high.
The preliminary sampling of defects may not be exhaustive, whereby some product defects may become apparent only after installation and it is not always possible to detect them because the vision system was created without taking this type of defect into account.
Besides, it cannot be assumed that during production the items which need to be analyzed will always be homogeneous, it may happen that different lots will bring along micro-changes of the product which will generate false recognition of faulty items.

Flexibility is the keyword for the application’s success
Flexibility is the keyword to reach a solution for some complex situations. It may happen that a vision sensor is initially envisaged, then replaced by a more complex system, possibly with video cameras. In this case often everything must be changed: hardware, the interface, programming and wiring, at a relevant cost. On the other hand, sticking to the system initially designed could imply a series of compromises with respect to initial demands, generating lack of satisfaction in the client and a relative loss in the image of the integrator.
Apart from the objective difficulty of going from one system to another, it must also be considered that getting to know several models of systems, with different programming modes, is in itself a waste of resources and therefore an additional cost; the ideal solution would be to have a single development platform, whatever the difficulty level of the vision issue may be.

The future lies in scalable systems
As a solution for this and other issues, VEA designed a single system capable of covering the range of products which go from the vision sensor to the most complex vision systems. This gave rise to IVIS, a scalable and expandable system, with a single powerful configuration tool, with costs starting from that of a vision sensor. The system is made up of a basic unit measuring only 12 x 12 x 4 cm which may be connected to any camera, from small models such as an M12 sensor right up to 10 Mpixel cameras, with a maximum limit of 32 cameras. Besides, the system includes an HMI operator panel and a PLC with a 1 mSec scan designed for artificial vision, where up to 64 modules with 8 I/Os may be connected, adding up to 512 inputs and 512 outputs. The internal PLC and HMI allow small plants to function without using any external devices.
Conveyor belt, rotating table or robotized selection machine may be designed even without external PLCs and operator panels, with a considerable saving as regards components and wiring. IVIS is a complete vision system, therefore programming and interaction occur by means of a normal PC monitor, without having to purchase an external terminal or connect a programming PC. For those who prefer an “invisible” system the possibility of programming using a portable PC remains open. IVIS is provided with a wireless mouse and keyboard, Wi-Fi and TCP-IP gate for communication. It may be expanded with serial communication or other types of module.
The speed of 500 acquisitions per second allows continuous controls without photocells, making it ideal for selection systems. IVIS can guide up to four robots simultaneously and carry out quality control, measurement, surface analysis and data matrix reading.

Measuring using vision systems
Besides quality control, vision systems may carry out measurements. Unfortunately they may often not be classified as measurement system because the fact that they generate numeric information does not imply that these may be considered as measurements, that is, that they satisfy predefined criteria of accuracy and repeatability. This is shown by the absence of appropriate certificates. In order to be classifies as a measurement system, a vision system must satisfy a series of criteria inherent to the environment whee it will be installed. IVIS vision systems include a metrological module with such properties as to allow its certification as a measurement system in the industrial environment. It allows micro-metrical measurements to be carried out directly on the production line compensating room temperature automatically, or even on every single component needing to be examined. Particular algorithms automatically correct any vibrations present in the environment and errors due to dust or other material which alights on the item to be measured.

High precision optical micrometers
With its range of 18 models of thermal compensation micrometers with 0.6 μm accuracy, VEA introduced real-time control of measurement repeatability. In this was it is possible to verify whether the measurement carried out falls within the measurability limits. In an industrial environment a vibration is enough to provide a wrong reading; the real-time repeatability allows to determine whether the measurement carried out is valid, preventing a defective product from being considered good on account of a momentary disturbance of the measurement. VEA’s optical micrometers are purposely designed to be installed in production systems. Along with the typical measurement function, they allow to carry out the quality control of the item and its surface analysis. They carry out up to 256 measurements at a time and 512 quality controls or surface analyses with a speed of 200 photos per second. Precision is guaranteed within a temperature range from 10°C to 60°C, thanks to the four-phase LTC (Laboratory Thermal Compensation) system which allows to obtain the same accuracy which would be obtained in a metrological laboratory (20° ±1°). Thanks to DAF (Dirty Advanced Filter) technology, measurements are accurate even on greasy or dusty items, with an analysis of the degree of dirt and stains.

An Industry 4.0 solution
IVIS complies with Industry 4.0 regulations for hyper amortization at 270%, both on account of the information transmission method and of its use as a measurement system. It uses a safe method for transmitting data to the server, which allows a temporary storage of data even if the plant is turned off or communication with the serer is interrupted. Besides, thanks to the UPS super-condenser unit, the system can communicate to the serer even when power is absent, such as, when the plant is temporarily turned off. It is impossible to lose even a single information; this makes the IVIS system completely compliant with the Industry 4.0 norms.