COMPARATIVE CASE STUDY ON SYSTEM-INTEGRATED MEASUREMENT TECHNOLOGIES

: The aim of the research is to make a comparison between system integrated measurement technologies in the field of engineering education in order to the students getting more detailed knowledge about the high level problem solving. A comparative case study was conducted with 3 different types of systems, as follows: Beckhoff, National Instruments, and HBM. The criteria of the systems are determined based on experience and the importance level of them was calculated by preference matrix. The ranks of the alternatives are calculated by Kesselring method, which provides the effectiveness value of the systems compared to the benchmark. The result of the paper shows a suitable method for selecting engineering systems


Introduction
Today, information is becoming increasingly important in the accelerated world.A great deal of information is available but unfortunately it is not a high standard.It makes a difference what information is available at what time.This kind of advanced intensive information might serve the development of technology.It does not matter what area of life is given as an example, that of a dentist's, a cinema show, a writer's year of birth, the current state of the ordered package.

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Pollack Periodica 15, 2020, 2 All the important information emerges from a lot of data collection and data processing [1], so it is very important to know from the beginning what tools and methods can be used to extract information.The intensive collection of information in industry is a major challenge, since the quantity and quality of information affects the product be manufactured.It is very important to know who, when and by what means, what tools, built the device in what way.These data are essential for future developments, or even a possible investigation of complaints.That is why it is fundamental part of the education that the students get up to date knowledge in field of measuring systems.Therefore, it is essential to be able to clearly compare desired industrial measuring systems for the production processes [2].
It is possible to compare different aspects/criteria systems with many types of decision making methods.

Selected industrial measuring systems
The article introduces classical industrial measurement technology solutions.The basis of the comparison (the smaller one) is provided by the systems applied at the Faculty of Engineering, the University of Debrecen.The article compares the different industrial measuring systems of three different manufacturers without completeness.

HBM
HBM is the market leader in the test and measurement technology and offers products and services for an extensive range of measurement applications in many industries.
The potential fields of application can be found in every branch of engineering and industry in both virtual and physical test and measurement.
HBM's product range covers strain gauges, load cells, force sensors, torque sensors, amplifiers and Data Acquisition Systems (DAQ) as well as software for structural durability investigations, tests and analysis.
In the HBM example the central pressure head and three displacement signals are measured (Fig. 1a is the signal amplifier, Fig. 1b is the displacement sensor Fig. 1c is the testing machine) how much the material rises at its two edges.The signals are provided by the force cell and the signal transducer sensors are evaluated using catmanEasy software (Fig. 2).It can parameterize the received signals in catmanEasy software.The resulting values can be monitored continuously.It is possible to export the signals, collected by DAQ in various formats.The catmanEasy software is not suitable for direct machine control.

National Instruments
For more than 40 years, National Instruments (NI) has been developing highperformance automated test and automated measurement systems, which help to solve engineering challenges now and well into the future.It is directly present in more than 50 countries.NI prepares engineers and scientists with systems, which accelerate productivity, innovation and discovery.
The main products of NI are the PC-based measurement and control systems, CompactRIO systems, PXI systems, software (for data collection, control, electronic tests, electronic instruments, wireless design and testing) LabVIEW, DIAdem.
An intelligent family house model has been implemented with a National Instruments device.Control and measurement tasks have been implemented (e.g.heating, cooling, access to garage door, irrigation, external as well as internal temperature).The model also provides remote access (Fig. 3) [3].

Main goals
Based on the diversity of excellence between the three manufacturers it seems rather difficult to make comparisons between them.However, owing to the combination of Kesselring and multi-criteria decision making methods clear evidence arises as how to qualify different systems in a measurable way.
The primary goal of the presented method is to apply any technical systems for a standard approach to diverse systems.This might balance out the incongruence of difference systems.

Multi-criteria decision making
Multi-Criteria Decision Making (MCDM) analysis is a rapidly growing aspect of operations research and management science.
A decision matrix A is an (M × N) matrix in which element a ij indicates the performance of alternative A i when it is evaluated in terms of decision criterion C j , (for Pollack Periodica 15, 2020, 2 i=1,2,3,...,M, and j=1,2,3,...,N).It is also assumed that the decision maker has determined the weights of relative performance of the decision criteria (denoted as W j , for j=1,2,3,...,N).

For example:
Let A = {A i , for i = 1,2,3,...,M} be a (finite) set of decision alternatives and G = {g i , for j = 1,2,3,...,N} a (finite) set of goals according to which the desirability of an action is judged.Determine the optimal alternative A* with the highest degree of desirability with respect to all relevant goals g i : 1) Determining the relevant criteria and alternatives; 2) Attaching numerical measures to the relative importance of the criteria and to the impacts of the alternatives on these criteria; 3) Processing the numerical values to determine a ranking of each alternative (Table I) [4], [5].

Table I
A decision matrix

Kesselring method
The method of system comparison was developed by Fritz Kesselring.This method was used for technical factors assessment that can be calculated by means of a ratio or interval factors.Kesselring developed a simple but very effective decision support method for the design process.Kesselring compared the data of products under investigation with the data of best product of a set ideal value.These data were the highest and got a score of 4 [6], [7].The value of the parameter is determined on the scale of 0-5 with the actual value of product with comparison to the ideal value.It is explained as:

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Pollack Periodica 15, 2020, 2 After collection of data, the Kesselring method is used to calculate the technical value of complex systems as: where x is the technical value of product; p i is the point value of parameters; p ̅ is the arithmetic mean; p max is the point value of ideal solution; n is the number of technical parameters.
Each parameter has different units.Kesselring formed a sequence of scale with measurements with a common denominator.The disadvantage of this method is that it does not take into account the different weights of parameters.It was solved by the Kesselring weighing method.v i stands for weighing factor of parameter were coded on the factor 0-10.The technical values of products were calculated with the weight factor of parameter as the follow: Here, x' can be up to 1 for complex system value.The Kesselring method is also used for the relative and absolute ranking of products.The system value is measured as: • 1 ≥ x' ≥ 0.8 = system is very good; • 0.8 > x' ≥ 0.6 = system is good; • 0.6 > x' ≥ 0.5 = system is appropriate; • x' < 0.5 = system is unsatisfactory.
The Kesselring method was originally used to measure machine tools; however, it can also be used for a complex system.In order to be effective, this method was designed to operate on evaluation factors that can be measured on the scale of ratio and intervals.
For the matching of procedures, the steps are as follows: 1. Choose an alternative; 2. Select evaluation factors; 3. Define the target function.(e.g.minimum for better smaller values, maximum for higher value function); 4. Specify the value of rating factor based on scale; 5. Specify the weight of rating factor.(for example: pair-based comparison or preference based comparison) [8], [9], [10].

Application of the methods
The three manufacturer's measuring systems have been compared with measurement methodology of complex systems.The main goal is to quantify the efficiency of each measuring system based on the determined parameters shown in Table II The methods applied as the follows as it can be seen in Fig 5 : • Selection of alternatives; • Definition of criteria; • Preferential matrix for determining the priority of criteria; • Specification of target functions for criteria; • Scoring of values-criterion for all alternatives; • Kesselring method for examining system efficiency.

Fig. 5. Steps of the methods used
The order priority of the preference matrix was determined on the basis of the chosen criteria (relationship of criteria).

The comparison is based on the 17 criteria (aspects) as it can be seen in
Table III.These criteria are the most important for selecting a measurement system.The effectiveness of measurements system is determined the value of the criteria.matrix is N [11].Basically consistency ration is a positive linear transformation of the Perron eigenvalue λ max as follows: CR = CI/CR, where CI stand for consistency index, CI = (λ max -n)/(n -1).RI stands for random index.Consistency ration is zero if and only if the pair wise comparison is consistent otherwise CR is a positive value.The threshold values of 0.1 (10%) has been accepted in the practice [12].The following table contains the value of consistency analysis.The calculated CR value is 0.073, that value can be accepted and the consistency is assumed in respect that there are 17 parameters in the calculation.4. The manufacturers rating has been calculated based on the weighted scores (1)(2)(3)(4)(5) (subjective comparison).The results can be seen in Table IV; 5. Weighted scores of measuring systems (summary); all three measurement system were well done based on the criteria set up (Fig. 6).The rating scores for mean scores are significantly affected by the following weighted points: E5-Data collection for reports; E6 -Data evaluation; E3 -Difficulty of programming; E8 -Sensor compatibility; E4 -User friendliness [11], [12], [13], [14], [15], [16].

Results
As it is shown in Fig. 6, all three measuring systems achieved similar scores.Based on weighted scores (x'), the manufacturers achieved the following scores, HBM: 0.677, NI: 0.702 and Beckhoff: 0.812.

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This means that all manufacturer's systems have received a good rating as described in paragraph 3.1 (0.8 > x' ≥ 0.6 = system is good, x'>0.8=system excellent).

Conclusion
Based on subjective and objective factors, the Beckhoff's industrial measuring systems are ahead of the above-mentioned competitors.The rating obtained is further corroborated by the Beckhoff company fact that the price of the measuring instruments and the programming software is absolutely free.
The method can be used as a basis for a customer satisfaction measurement, which can be the basis for future product development.

Fig. 1 .
Fig. 1.Physical devices of the HBM measuring system

2 .
Best value criteria have been considered; 3. The low level of inconsistency of a pair wise comparison is a necessary condition to generate the acceptable result.The Consistency Ratio (CR) is based on the fact that the dominant eigenvalue of a consistent pair wise comparison SYSTEM-INTEGRATED MEASUREMENT TECHNOLOGIES 67 Pollack Periodica 15, 2020, 2 .