DE2347190B2 - Measuring device for measuring the time of flight of electromechanical relays, the contacts of which bounce - Google Patents

Description

45

The invention relates to a measuring device for measuring the flight time of electromechanical changeover contacts Relays with contacts bouncing. The flight time is defined as the time between the last bounce of the first actuated contact side and the first bouncing of the second actuated contact side.

Most of those commonly used in telecommunications Relays do not immediately and completely close their contacts; the contacts open one or more Times before it goes to sleep. Such meiin.ii.iges opening and closing becomes bouncing called. Even when contacts are opened, the contact springs can overshoot and turn on or again close several times before remaining open. In this case, too, one speaks of bouncing.

When using relays, their bounce behavior is often of interest. It is the object of the invention therefore, to specify a circuit arrangement for a measuring device that takes an aircraft measurement into account of bouncing enabled. The measurement result should be as digital as possible in a way that is machine-compatible are output in order to be able to carry out serial measurements with the smallest possible errors.

It's been common knowledge the entire Bouncing process ηώ HBfe of an OszwOgraphea visible to machea However, this procedure is too time-consuming for a row ravage cmd za slow. It would be It is conceivable to accelerate this process by having photodiodes on the screen of the oscilloscope which determine the individual contact status changes and after converting the Output the flight time digitally in time units. This measuring method is also for serial measurements too complex and too imprecise.

According to the invention, the object is achieved in that the contacts of the relay to be measured over an evaluator with a counter that is incremented at a high frequency of a generator, and the Counters are connected to an output device that opens a gate with the contact state change of the first actuated contact side and the The frequency coming from the generator to the counter allows every contact change to occur the first activated contact side as d, e possibly lci / te contact state change before the first Contact state change of the other contact side is considered and therefore the counter every time at whose occurrence is deleted and restarted, and that when the contact status changes for the first time, the andeen contact page after the last start of the counter this stopped and the result output will.

The measuring device according to the invention has the advantage. that only a single precisely working counter needs to be used. The incremental cycles of the generator for the counter can be as small as desired be selected, they are only limited by the switching times of the switching elements used, so that a arbitrary resolution of the measurement time and thus an extremely small measurement error can be achieved.

An example of the invention is explained with reference to the drawing. While in F1 g. 1 shows a circuit arrangement is shown with which the measurement of the flight time can be made is in FIG. 2 the temporal Sequence of the individual switching and measuring processes when measuring a simple changeover contact and in F i g. 3 recorded during the measurement of a subsequent changeover contact, in the drawing only those for the Understanding of the invention required facilities and timing shown.

As soon as the contact £ (Fig. 1) is closed, the relay P responds and actuates its changeover contact. This can be a simple changeover contact u or a follow-up changeover contact fu . Each of these contacts has two sides, a working side a and a resting side r.

These changeover contacts are connected to an evaluator A. This evaluator A is equipped with switching means that monitor which contact side of the contacts connected to it make contact status changes when. The evaluator A also contains, among other things, a pulse shaper that converts the pulses arriving from the contacts to be tested into a form that is required by the subsequent devices for further processing.

With the help of a Umschnltekontaktes tv, the pulses obtained in this way can either be passed on directly to the gate circuit T or via a time filter F. This time filter recognizes a change in the contact state only after a preselectable time, so that

Bruises that are shorter than this time, not as such be rated.

In Fig. 2 the timing of the individual processes is shown with a simple switchover contact u - At time (1, the relay P is brought from the non-excited state 0 to the addressed state 1, at time (I the relay is switched off again ( Fig. 2a).

When the first K Dn clock change of state of the most recently actuated contact side, i.e. the normally closed contact side r (FIG. 2c), the gate circuit Γ is opened at time (2) so that the counting clocks generated by a frequency generator G can pass through to a counter Z. (F i g. 2e). the counter is thus started and incremented until the time Q where the contact side r again changes its contact state. at this moment, the counter Z is reset to its initial position and at the same fortgeschalte with the frequency of the generator g again ! until the time / 4. This is done so fot. as the break contact r before the first contact status change of the other contact side Senen Kontaktzusland changes

In order to reduce the number of counter reset and start processes, it is also possible to only operate these counter operations when the normally closed contact side changes from its closed position ζ to the open state 0. This process is illustrated in FIG. 3e explained in more detail.

At time (4, the counter started again. At time iS, however, the normally open contact side a (FIG. 2b) briefly changes from the open state 0 to the closed state ζ . This contact state change is recorded by the evaluator A , whereupon the counter Z is stopped. the Zählerergehnis arrives at ^e: .nde the measurement period to an output S indicating u is the time of flight of Umschaltekontaktes in consideration of the clock frequency of the frequency generator G In this example, the time of flight of Umschaltekontaktes takes u until time (5 from the time (4..

In the same way, the flight time of the Umschaltek > »Taktes i / betm opening the relay P can be measured. Since the individual processes are repeated in the same way, they are not described again. This flight time runs between the times <9 and MO. as in Figs. 2d and 2e is shown.

The first change in the contact state of the second actuated contact side provides the correct stop time for the counter Z in most cases. However, it is conceivable that the central spring oscillates between the working and the rest side while the contact is being switched. The rest side r of the changeover contact opens and closes while the working side a has closed for the first time or several times. Since the definition for the time-of-flight measurement should also apply in this case, the timing is different from that in FIG. 2 shown. Such a timing is shown in FIG. 3, but this time instead of a simple switchover contact u, a subsequent switchover contact fu is to be measured. This subsequent changeover contact also has a working side a and a resting side r, but here the working side a must first close before the resting side r can open.

In Fig. 3 only the processes are shown which take place when the relay P (FIG. 3a) is energized. After the relay P has been energized at time / H, the normally closed contact side a of the subsequent changeover contact fu (FIG. 3b) is closed. In response to a signal from evaluator A , counter Z (FIG. 3d) is started. The same thing is repeated at time r13. the counter reading is now also cleared.

Since the time (14 tranquility side r (F i g. 3 c) is carried out, the first contact state change is stopped at this moment, the counter Z The count is initially retained up to the time (15 again a contact state change of the contact a side occurs. Now and / um At time r16, the counter is reset and started again.

At the check point (17, the evaluator A records a change in the contact state of the contact side r and again stops the incrementing of the counter Z. However, since the contact side a now remains closed, the counter reading Z also remains unchanged until the set measuring time has ended and the The counter reading is output in the manner already described.

As already indicated, the number of resets and new starts of the counter Z can be reduced in that a command for this process is only issued when the central spring of the switching contact executes a movement in a certain direction. According to FIG. 3e, this is only the case when the working side a of the subsequent changeover contact fu moves from state 0 to state ζ , i.e. only at times / 12, Π3 and (16, but not at time (15.

Dit further contact status changes on the contact page make the point in time (17, i.e. the points in time (18 and (19) are of interest in this context no further and therefore do not need to be taken into account.

The previous description of the time-of-flight measurement referred to a circuit arrangement according to FIG. 1, in which the contact w is not in the contact position shown, but in the other contact position, i.e. That is, the filter F is not switched on. When this filter is used, all short-term bruises, for example in FIG. 2b at time (S and (8, in FIG. 2c at time (10a and in FIG. 3b at time (12)). As a result, the flight time FZ according to FIG. 4 and (5 lying, but between (4 and 6a , displayed. The start of the counter is moved from time (8 to time (9 and from (12 to (13.) - and take-off commands, but other flight times are also measured.

For this purpose 2 sheets of drawings

Claims (4)

Patent claims: 23 t. Measuring device for measuring the time of flight of Uraschschaltkontakten electromechanical relays. S eieren contacts bounce, characterized in that the contacts (ar u) of the relay to be measured (P) via an evaluator (A) with a counter (Z), which is incremented with a high frequency of a generator (G) , and the ω counter (Z) are connected to an output device (S) that a gate circuit (T) with the change of compact state ((I or Λ2) of the first actuated contact se fr or aj opens and the frequency coming from the generator (G) to the counter (Z) allows every contact state change (ß. A or il3. RlS. Tlfy of the first actuated contact side fr or aj to be considered as the possibly last contact state change before the first contact state change on the other contact side (a or ^ and therefore the counter (Z) is deleted and restarted each time it occurs, and that the first change in the contact state of the other contact side (ft or tl7) after the last status of the counter fZJdteser is stopped and its status is output . 2. Circuit arrangement according to claim!. Characterized in that with simple changeover contacts (u) the erasing and starting (Q, Ά) of the counter (Z) only takes place when the first actuated rest side ^ of the changeover contact fu / is closed. 3. Circuit arrangement according to claim!, Characterized in that in the case of sequential switchover contacts (fu) the deletion and starting (712. f13. L \ f>) of the counter (Z) only when the first activated working page (a) of the subsequent Changeover contact (fu) takes place. 4. Measuring device according to claim 1, characterized in that the counter (Z) etn time filter (F) by means of a changeover contact (w) can be connected upstream so that bruises that last less than a preselectable time are not evaluated.