‘Condition Monitoring' For a greater availability of the machine

From the modules of oscilloscope until the servoaccionamientos instrumented with sensors, going through the chip of monitoring inside each Automation PC and by the modules of analysis of vibrations with integrated intelligence, B&R offer all the possibilities to be able to take the pulse of the machine, without need of external devices.

‘Condition Monitoring' Is already an integral part of all the systems of B&R and, in consequence, of all the machines automated with technology B&R. The predictive maintenance based in a constant monitoring of conditions helps to avoid time of inactivity no scheduled and reduces the cost of storage of spare pieces. Using the measurements on the state of the machine like entrance for bows of open and enclosed control, is possible to increase significantly his useful life and contribute to a substantial reduction of costs.

The efforts of development of the mechanical engineers are giving good results to measure that increases the functional density and of power of the machines of production. This means that it requires a lower number of machines to produce the same quantity and complexity of products, which reduces the costs of production and contributes competitiveness to manufacturers of machinery.

However, this increase of the efficiency also does that the producers depend more than the own machines. The capacity to produce more units by hour means that each hour of inactivity is costlier. And any one that have used a machine knows that the time of inactivity never can avoid completely.

The strategies of traditional maintenance have a thing in common: to win a small percentage of availability of the machine, pays a very high price. This sucede in relation with a reactive maintenance, oriented to damages, where the components of the system carry to the limit and only replace when they fail. The only form to guarantee the availability of the machine in this stage is keeping a stock of spare pieces and having immediately of qualified personnel and of the necessary equipment. The traditional strategy more spread, however, is the one of the preventive maintenance at intervals fixed based in the experience. Although this approach has the clear advantage to be able to plan better the time of inactivity, definitely is not the best solution and comports a considerable financial risk. On the one hand, it is necessary to purchase and substitute the pieces although the original are far of the end of his useful life. By the another, does not have of a reliable protection against time of inactivity no scheduled, for example, when the asymmetric tension does that some parts fail before the interval of maintenance.

Minimise the time of inactivity as much as possible and elaborate a strategic plan of maintenance of forced fulfillment: these are the aims of any manager, that no only base in the price of acquisition when evaluating new machines, but also in the global costs during all his useful life. The only form of repercutir significantly in the total cost of property is maximizando the time of operation of the machine and, at the same time, reducing to the minimum the costs of maintenance. This is reason more than sufficient for replantear the strategies of maintenance in general.

The best form to optimise the relation between availability of the machine and costs of maintenance is replacing the intervals of fixed maintenance by a dependent predictive maintenance of the conditions. This involves to program the maintenance when the changes in the parameters supervised indicate imminent failure. The advantage, in this case, is that the components can be still working until much more near of the real end of his useful life, that is used to to be much more late of the estimated in the intervals of traditional maintenance. Besides, no repercute in the planning since the maintenance required can realizar during the rests of production programmed regularly. The risk to keep an unnecessary stock of spare pieces also minimises , since they only have to substitute the components affected. Also it represents a reliable form to avoid failures that can result of an oversight of maintenance.

So that all this was possible, is necessary to supervise of continuous form the parameters of state of all the team, and these data have to evaluate properly to determine which pieces require maintenance. “This can base in simple signals and values of measurement such as the temperature or the pressesure that recopilan using the modules of And/S X20 or X67", explains Bernhard Eder, commercial director of B&R. "Besides, B&R also offers specific modules, like modules of control of valves with detection of time of conmutación integrated or functions of oscilloscope”.

In definite, the systems of automation of B&R integrate of native form a sinfín of options to supervise the signals of state. This includes the servoaccionamientos Acopos with function of monitoring of the engine integrated , as well as the Automation PC of B&R, instrumented with an integrated circuit for automatic diagnostic. The last incorporation to this selection is a new module in the series X20 for analysis of vibrations.

“The technology of sensor used to obtain the signals, definitely, is important, but the alone sensors are not sufficient”, explains Werner Paulin. Paulin Has of a long experience in international application since it joined to the company in 1997 and at present is the director of International Sales of B&R for China. “The key to program the intervals of maintenance to substitute the components to time, and no too early, is to interpret properly the signals registered. That is the only form to predict with precision the problems of development”.

Although Condition Monitoring has existed from does decades, has taken a lot in consolidating inside the manufacture of traditional machinery. The complex mathematics involved have required always big and costly specific computer systems, that to his time had to program experts of the fields of the science of the materials and of the mechanics of swing. Thus, Condition Monitoring limited to the systems whose failure could cause enormous costs.

The every time lower scale of the components microelectrónicos has deleted, since, the need of a costly external wiring. The module of analog entrances X20AI2636 of B&R, for example, comes of series with essential functions like a comparator with histéresis. The module Condition Monitoring X20CM4810 of B&R, that is applying at present to pilot customers selected, converts the signals of reading of the sensors of acceleration to more than 70 specific values. This allows to supervise even the patterns of swing more complex in an only channel.

The developers can configure easily which factors have to supervise in Automation Studio of B&R, without requiring big knowledges of the mathematical functions, which resolves many of the problems in matter of software and interfaces. During the operation, the significant values send to the CPU of the system through Powerlink and afterwards can use directly in the software of application. “For the first time, the manufacturers of machinery are able to offer Condition Monitoring no like an option of high level, but like a standard characteristic entirely integrated ”, affirms Paulin. “Like result, can give to his customers guarantees of availability with a risk attributed considerably lower”.

The operarios of the machine also can benefit of the integration of Condition Monitoring with the systems of internal logistics of the company. When the machine identifies the need of maintenance, for example, can send automatically a reminder to the department of maintenance or shopping with the pieces required. This avoids that they neglect requests or that assign of wrong form and guarantees the availability of the correct piece in the necessary moment, without having to keep a big stock in situ.

But the maintenance is not the only area where open new possibilities by the fact to have of data of condition processed previously in real time. The data of condition registered also can send to the software of automation to obtain an additional functionality. “This allows to adjust the speed with the aim to prolong the time before the maintenance, for example, or to compensate the holgura or the delays of conmutación, and can keep some conditions of optimum operation”, explains Eder. “This type of adaptative operation can contribute even more to a greater availability and to an useful life longer, what, in definite, represents a more efficient utilisation of the resources and some inferior unitary costs”.