Correction D'un Rapport

[Invité haldir]

Bonjour tous le monde,

Comme dit dans le titre j'ai besoin d'aide pour vérifier mon rapport. Le sujet est la réalisation d'un module d'alimentation pour banc d'ajustage de relais.

Si vous pouvez m'expliquer mes erreurs sa serais génial. Merci a vous.

Modernization of a supply module for bench of fitting of relay.

Leach International Europe S.A Company made of the permanent modernization of its installations, to develop innovative solutions and to keep its manufacturing processes at the forefront of progress its absolute priority. It is thanks to these objectives that it is currently in place of leader in the manufacture of hermetic and time-delayed relays for harsh environments. It is in this context that the O&M department (Organization and methods) has been given the project to modernize relay's fitting benches.

The relay fitting consists to settle opening's and closing's voltages of contacts and to adjust the maintenance pressure. For modify the closing voltage, we can exploit the magnetizing of the coil relay. Then, the opening tension of the relay and the pressure of the contact can be regulated via the mechanical resistance of the contacts and for certain models by a return spring.

The subject that I have been entrusted consists in developing a electronic card who permit to test the various relay's operating voltage: i.e. the tension to which the first contact leaves the low state, the tension at which the last contact arrives at the work state, the tolerance which consists in calculating the difference of the two preceding voltage and finally the voltage to which the last contact return at the low state (see figure 1).

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Figure 1: relay's flow chart.

The purpose of this module is to generate a slope of increasing and decreasing tension on various patterns, to detect the relay's swing and to measure the tensions previously quoted. These data will be transmitted by RS232 towards an automat or a PC. Voltage's Slopes to be realized are:

· 0 – 6V

· 0 – 12V

· 0 – 28V

· 0 – 75V

· 0 – 120V

Its slopes must be realized in less than 3 seconds. Moreover, the module will have to allow user to choose between an automatic mode (the support prolonged on a button launches the growth of the curve and if it is not pressed its decrease), or a manual mode where the slope will be ordered via a potentiometer.

It has been chosen to used a module containing a transformer with multiple secondary. To carry out my tests, it was given to me a transformer which was envisaged at the origin for another project which was abandoned. Transformer's exits are:

- 5V once rectified 7V

- 12V once rectified 17V

- 22V once rectified 31V

- 60V once rectified 85V

- 90V once rectified 127V

Unfortunately, this transformer is not completely appropriate for this application. Indeed, by taking account of charging's voltage's falls (due to components and the regulator's minimal voltage). Output's voltages, once rectified, are too close to the desired maximum values, which means that certain range of tension are not entirely carried out.

The circuit is relatively simple, a first part allow to select the transformer's coil (see figure 2). The transformer's common goes directly on a diode's bridge, whereas the exit is selected via TRIACS. The command of the latter is isolated via optocoupler and a converter 5V-5V. This last comes from a microcontroller.

Figure 2 : sélection de l'enroulement

The second part (see figure 3) consists to generate a voltage's slope of exit. The regulator is mounted normally with two resistances on the adjustment's pin but all the originality of this circuit comes from the addition of a generator of current mounted in parallel with resistance being between the mass and ADJ's pin (connector block M3 on the fig3). This generator makes it possible to derive part of the current from ADJ's pin what causes a reduction in the exit voltage.

The ordering's voltage of the current's generator (AOP's pin +) is provided by a unit made up of a binary counter produced via a microcontroller, an analogical numeric converter and amplifier (allowing to adapt the exit voltage of the converter). The counter is incremented or decreased at a frequency of 100kHz provided by a NE555.

Figure 3 : Régulateur de tension

The following part makes it possible to select resistances to adjust the regulator and to calibrate the exit measure bridge. Measurement is taken via an external digital analogical converter. This one is carried out with each time the main microcontroller receives the information indicating the change of relay's state.

Finally, you find a small circuit allowing for choice between the manual mode and the automatic mode. The selection is carried out via a comparator which will monitor the tension of the potentiometer. As soon as this tension passes below the threshold, the comparator rock the exit of a multiplexer thus allowing to pass from the automatic mode to the manual mode.

To manage the communication between the various modules of the bench, I have been to develop a card allowing the multiplexing of the RS232. She consists of a microcontroller who manages the reception of the data and sending them towards their recipients chosen by a multiplexer.

The supply module is finish. It remains to draw the final card and to dimension the transformer.

For the bench in itself, it remains enormously of work. It is still necessary to make the interface man machine and the connection with the magnetic bench.