JPH0573796A - Relay scanner device - Google Patents

Abstract

PURPOSE:To reduce the defective contact due to formation of an insulating film in the contact part of a relay by providing a voltage applying system which selectively applies a prescribed voltage to the contact of each relay. CONSTITUTION:Relays 2, 11, and 12 are selectively turned on/off in accordance with the indication of a CPU 7 by a selector 3. For example, a contact (a) of the relay 2 is turned on when two contacts of the contact (a) are cleaned. A contact (a) of the relay 12 and a contact H of the relay 11 are simultaneously driven at the time of cleaning one contact. A contact (b) of the relay 12 and a contact L of the relay 11 are simultaneously driven at the time of cleaning the other. Thus, a close loop circuit consisting of turned-on contacts, a DC voltage source 9, and a resistance 10 is formed. As the result, a prescribed voltage is selectively applied to contacts of the relay 2 to break down the insulating film formed on the surface of contacts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay scanner device, and more particularly to reducing the influence of contact resistance of relay contacts.

[0002]

2. Description of the Related Art A relay scanner device is widely used for measuring voltage signals at a large number of measuring points with one measuring device.

FIG. 3 is a block diagram of an example of a conventional relay scanner device. In the figure, 1 is a large number of measurement points CH1.
These are N sets of input terminals provided corresponding to CHN, and are connected to the corresponding input terminals of N relays 2. The control terminal of these relays 2 has a selector 3
The corresponding output terminals of are respectively connected. The output terminals of these relays 2 are commonly connected to the input terminals of the preamplifier 4. The output terminal of the preamplifier 4 is connected to the input terminal of the A / D converter 5. The A / D converter 5
The output terminal of is connected to the input terminal of the CPU 7 through the photocoupler 6. A part of the output terminal of the CPU 7 is connected to the control terminal of the selector 3 via the photo coupler 8.

In such a configuration, the CPU 7 gives an instruction via the photocoupler 8 to the selector 3 which input terminal 1 corresponds to which relay 2 to selectively turn on.
When the selected relay 2 is turned on, the voltage signal input to the corresponding input terminal 1 is applied to the preamplifier 4 and amplified so that the voltage level can be converted by the A / D converter 5. The voltage signal input to the A / D converter 5 is converted into digital data and is converted to C via the photo coupler 6.
It is taken into PU7 and required digital processing is performed.

[0005]

However, in such a conventional relay scanner device, if patina is generated on the surface of the contact of the relay 2 or impurities adhere to form an insulating film, the contact resistance increases. There is a problem that stable measurement cannot be performed when the voltage level of the voltage signal is low.

The present invention has been made in view of the above problems, and an object thereof is to provide a relay scanner device capable of improving contact failure due to formation of an insulating coating on a contact portion of a relay. is there.

[0007]

SUMMARY OF THE INVENTION A relay scanner device according to the present invention is a relay scanner device which selectively outputs a plurality of measurement signals via relays, and is formed on the surface of a contact on the input side of each relay. It is characterized in that a voltage application system for selectively applying a voltage for electrically destroying the insulating coating is provided.

[0008]

By applying a voltage to the contact having the insulating coating through the voltage applying system, the insulating coating is destroyed and the contact resistance of the contact is reduced, and stable measurement can be performed even with a voltage signal having a low voltage level.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals and their description will be omitted. In FIG. 1, reference numeral 9 denotes a DC voltage source, a negative terminal is connected to one end of contacts H and L of a relay 11 via a resistor 10, and a positive terminal is connected to one end of a plurality of contacts a to 2n of a relay 12. It is connected. Relay 11
The other end of the contact H is connected to one input terminal of the preamplifier 4, and the other end of the contact L of the relay 11 is connected to the other input terminal of the preamplifier 4. Contact points a to 2 of relay 12
The other end of n is connected to the input side of the contacts a to n of the corresponding relay 2. Similarly to the relay 2, these relays 11 and 12 are selectively turned on and off by the selector 3 according to the instruction of the CPU 7.

FIG. 2 is a timing chart for explaining the operation of FIG. The operation of FIG. 1 is a measurement mode in which the relay 2 is selectively turned on and off to measure the voltage signal input to the input terminal 1, and the contacts of the relays 11 and 12 are selectively turned on and off. Then, by applying a voltage to the input side of the contacts a to n of the relay 2, the contacts a to n of the relay 2 are applied.
It is divided into relay contact cleaning mode for cleaning.

That is, in the measurement mode, any one of the contacts a to n of the relay 2 is selectively turned on as shown in FIGS. 2A to 2C, but each contact of the relays 11 and 12 is driven. Are all kept off during that time, as shown in FIGS.

On the other hand, in the relay contact cleaning mode, one of the contacts of the relays 2, 11 and 12 is selectively turned on at the same time. For example, 2 of contact a of relay 2
When cleaning one contact, the contact a is driven on during that period as shown in FIG. 2A, and when cleaning one contact, as shown in FIG. Contact H of relay 11 as shown in J)
Are driven at the same time, and when cleaning the other contact, as shown in FIG.
As in (K), the contact L of the relay 11 is driven at the same time.

By selectively turning on the corresponding contacts of these three relays 2, 11 and 12 simultaneously, a closed loop circuit is formed by these ON-driven contacts, the DC voltage source 9 and the resistor 10. A voltage for electrically destroying the insulating coating formed on the surface of the contact is selectively applied to the second contact, and the insulating coating formed on the surface of the contact is destroyed. The voltage to be applied may be several V, and the application time may be about 100 ms. If a voltage higher than this is applied for a longer period of time, carbon may be deposited on the contacts to cause a problem.

When the insulating film is broken, the contacts H and L of the relay 11 are alternately switched and the contacts of the contact set of the relay 2 are also individually turned on, so that the measurement signal connected to the input terminal 1 is measured. The output voltage of the DC voltage source 9 does not adversely affect the source system and the measurement system after the preamplifier 4.

[0015]

According to the relay scanner device according to the present invention described in detail above, the following effects can be obtained.

The contact resistance can be reduced by selectively applying a voltage for destroying the insulating film to the input side of the contact of the relay that selects the input terminal as required, and stable even with a voltage signal having a low voltage level. Can measure.

In cleaning the contact of the relay, the voltage for destroying the insulating film does not adversely affect the measurement signal source system and the measurement system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a timing chart illustrating the operation of FIG.

FIG. 3 is a configuration diagram of a conventional device.

[Explanation of symbols]

 1 Input terminal 2,11,12 Relay 3 Selector 4 Preamplifier 5 A / D converter 6,8 Photocoupler 7 CPU 9 DC voltage source 10 Resistance

Claims (1)

[Claims] 1. In a relay scanner device for selectively outputting a plurality of measurement signals via relays, a voltage for electrically destroying an insulating film formed on a surface of a contact is provided on an input side of each relay. A relay scanner device comprising a voltage application system for selectively applying the voltage.