JP2591042Y2 - Relay drive - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay drive device, and more particularly, to prevention of malfunction of a relay caused by noise.

[0002]

2. Description of the Related Art As one type of a relay driving device, as shown in FIG. 2, data DATA output from a signal source 1 at a constant update cycle is output to a strobe signal ST output from the signal source 1.
There is a configuration in which the latch 2 is taken into the latch 2 in accordance with RB ', and the relay control signal RLYC is output from the latch 2 to the relay driver 3 to drive the relay 4.

FIG. 3 is a timing chart showing an example of a conventional operation in such an apparatus. (A) De is applied from the signal source 1 to the latch 2 - a data DATA, "1", is intended to become three states "indeterminate" and "0", the update period of time _{t 0} (e.g. 125ms)
Will be updated. (B) is a strobe signal S output from the signal source 1 to the latch 2 in synchronization with the update of the data DATA.
In TRB ', a dash "" indicates that the operation is performed by negative logic. (C) is a relay control signal RLYC output from the latch 2 to the relay drive circuit 3. Each time a strobe signal STRB 'is input, the state of the data DATA at that time is fetched. Strobe signal S
The state is maintained until TRB 'is input. (D)
Indicates the operation state of the relay 4, and the relay control signal RLYC
The operation state changes after a lapse of a fixed time t ₁ (for example, 4 ms) from the change in the state.

[0004]

However, according to such a conventional configuration, the correct data DATA is obtained from the signal source 1.
Although noise is output, noise is mixed in the data transmission line up to the latch 2 and the data is input to the latch 2.
Strobe signal STRB when DATA is undefined
When 'is input, the relay 4 eventually malfunctions, and there is a problem that the state is maintained until the next time the data DATA is updated.

The present invention focuses on such a problem, and an object of the present invention is to provide a highly reliable relay drive device capable of preventing a relay from malfunctioning due to noise.

[0006]

According to the present invention, which solves such a problem, data output from a signal source at a constant update cycle is taken into a latch in accordance with a strobe signal output from the signal source. In a relay driving device that outputs a relay control signal to a relay driver to drive a relay, the signal source repeatedly outputs the same data together with a strobe signal a plurality of times in each data update cycle to the latch.

[0007]

The same data is repeatedly input to the latch a plurality of times together with the strobe signal within the data update cycle from the signal source. On the other hand, it is highly possible that noise is mixed in irrespective of time with respect to the strobe signal. This allows
Even if noise mixed into the transmission line of data DATA is taken into the latch according to the strobe signal, correct data DATA without noise is taken into the latch according to the strobe signal before the relay operates. Therefore, the malfunction of the relay can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. The block diagram of the apparatus to which the present invention is applied is the same as that of FIG. 2, but is characterized by the output timing of the data DATA and the strobe signal STRB 'from the signal source 1. That is, in the present invention, the signal source 1 repeatedly outputs the same data a plurality of times together with the strobe signal within each data update cycle.

FIG. 1 is a timing chart showing an example of the operation of the device of the present invention, and is denoted by the same reference numerals as in FIG. To the signal source 1 latch 2, (in the embodiment 3 times) several times the same de in the update period of time t _0, as shown in FIGS. 1 (a) - outputs a data DATA, (b ), The strobe signal STRB 'is also output a plurality of times (3 in this embodiment) in synchronization with the output of the data DATA.
Times) output. Latch 2 holds data DATA in accordance with strobe signal STRB 'and outputs a relay control signal RLYC corresponding to data DATA. Then, the relay driver 3 outputs a relay control signal R having a constant level.
After a lapse of time corresponding to the integration of LYC for a predetermined time (in this embodiment, t _{1 for} three strobe signals STRB ′), the contact state of the relay 4 is changed.

The data DATA of FIG. 1 repeatedly outputs a "1" level during the first to third strobe signals STRB ', and outputs "0" during the fourth to sixth strobe signals. The level is output repeatedly. By the way, "0"
When the level of data DATA becomes "indeterminate" due to noise being mixed in synchronization with the fifth strobe signal STRB 'while the level data DATA is repeatedly output, the latch 2 Captures the "1" level, for example, as shown in (c), and holds that state until the next sixth strobe signal STRB 'is input. Then, when the sixth strobe signal STRB 'is inputted, the noise disappears and the level of the data DATA becomes "0" again, and the latch 2 takes in the "0" level. In this case, since noise of reverse polarity is mixed in the data DATA so as to be synchronized with the fifth strobe signal STRB ', the relay driver 3 outputs the sixth strobe signal STRB'. Then, the contact state of the relay 4 is changed after a lapse of a time longer by about one strobe signal STRB '.

With this configuration, the data D
Even if noise having a polarity opposite to that of ATA is mixed, the influence of the noise is limited to the unit of one strobe signal STRB ', and does not greatly affect the state change of the relay 4 and consequently. Has high reliability.

In the above embodiment, the data update period t
_In the example described above, the same data DATA is output three times together with the strobe signal STRB 'immediately after the data update within ₀ , but in this case, the last strobe in the data update period is output. If noise is mixed in synchronism with the signal STRB '(for example, third and sixth), a malfunction occurs because the strobe signal STRB' is not input after that in the data update cycle. However, such a disadvantage can be solved by outputting the strobe signal STRB 'a plurality of times during the entire data update period.

[0013]

[Effects of the Invention] As described above, according to the present invention,
It is possible to provide a highly reliable relay drive device capable of preventing a relay from malfunctioning due to noise.

[Brief description of the drawings]

FIG. 1 is a timing chart for explaining the operation of an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of an apparatus to which the present invention is applied.

FIG. 3 is a timing chart for explaining the operation of a conventional device.
It is.

[Explanation of symbols]

 1 signal source 2 latch 3 relay driver 4 relay

Claims (1)

(57) [Scope of request for utility model registration] 1. A capture data outputted from the signal source at a fixed update period in the latch according to the strobe signal output from the signal source, the relay drive to drive the relay output from the latch to the relay driver as a relay control signal In the device, the signal source repeats the same data with a strobe signal a plurality of times within each data update cycle and outputs the same to the latch.