JPS6132426Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a contact input circuit applied to a digital circuit that handles various contact outputs as inputs.

In recent years, circuit configurations that use information via contacts such as relays and switches as input to digital circuits have become commonplace and are used in various electronic devices, but if a failure occurs in the input circuit that is directly connected to the contacts. In this case, it is impossible to detect this, and the input circuit output under a fault condition is recognized as legitimate information from the contact, resulting in a drawback that the operation of the device is inaccurate.

The purpose of this invention is to eliminate all of the drawbacks of the conventional technology at once.The present invention uses a processor as an input circuit, sends out alternately inverted confirmation outputs from the signal source, and inverts these confirmation outputs to connect the contacts. At the same time, the inverted confirmation output is given to the processor as a confirmation input, and the signal from the other pole of the contact is used as the information input to the processor. ,
The present invention provides an extremely effective contact input circuit that can immediately detect the occurrence of a failure in the input circuit by determining the validity of information input.

Hereinafter, details of the present invention will be explained with reference to figures showing embodiments.

In the block diagram of FIG. 1, an inverter IN is provided that provides an inverted output to one pole B of the switching contact rl, and also has an information input X, a confirmation input Y, and a confirmation output Z from an internally provided signal source. A processor CPU such as a microprocessor is provided, and the confirmation output Z of the output circuit OF sends out a signal that is alternately inverted as "H" (high level) and "L" (low level) at a fixed period. This is what is given to the input of the inverter IN.

Also, the inverted output of the inverter IN is the confirmation input Y
On the other hand, the other pole C of the contact rl is used as the information input X, and furthermore, the confirmation output Z is directly given to the closing pole F of the contact rl.

Therefore, depending on the operation and recovery of contact rl, the information input The signal is always given, and by determining the validity of information input It is possible to detect whether or not this has occurred.

Figure 2 shows the processor that makes the above decision.
This is a flowchart showing the operation of the CPU. First, it sends a confirmation output "L" to Z, checks each input "X, Y", and then determines whether "Y="H"?" If the result is YES, it is a normal state, the information input X is determined to be valid, and "process A according to the contents of X" is performed.

Next, send the confirmation output “Send “H” to Z”, check each input “X, Y”, and then “Y=
“L”? ”, and if the result is YES, it is a normal state, the information input X is determined to be valid, and “process B according to the contents of X” is performed.

In contrast, “Y=“H”?” and “Y=“H”?”
“L”? ” is NO, it is determined that a failure has occurred in the input circuit IF, and the process moves to “failure detection”.

However, when separately collating the results of processes A and B, there is no need to specifically perform "fault detection";
The main routine may be repeated as indicated by the dotted line.

In addition, Processes A and B indicate the respective processing contents, such as the case where the operation and recovery information of contact rl is sent twice as each individual code and transmitted to a remote point, and the same information is transmitted to two different types. Display by code,
This is suitable for checking and confirming this on the other party's side.

FIG. 3 is a block diagram showing another embodiment,
Each individual contact rl ₁ , rl ₂ with each pole B 1 , B ₂ , F ₁ , F ₂ , C ₁ , C ₂ is provided, and these other poles C ₁ , _{C 2 are} used as information inputs X ₁ , ₂ , and a flip-flop circuit (hereinafter referred to as
FFC) Uses FF and constant period control pulses
The CP alternately inverts FFC and FF, and sends out confirmation outputs Z of "H" and "L" from the output, and also feeds the CP to the start input S of the processor CPU, thereby starting the processor CPU. Other than that, it is the same as in Figure 1, and the processor
If the CPU counts the number of times the control pulse CP is applied and makes the same determination as shown in FIG. 2 for each input X ₁ , X ₂ , Y, the same result as described above can be obtained.

However, if oscillators with different frequencies are provided for each input X ₁ , X ₂ , Y, and their outputs are controlled according to the status of each input X ₁ , X ₂ , Y, 3
The configuration shown in FIG. 3 is suitable for this purpose because a decomposed frequency signal is obtained by wave combination.

In addition, the number _of contacts rl, rl ₁ , rl ₂ is determined depending _on the conditions, and information inputs X, The same effect can be achieved even if a modified version is used, and the present invention can be modified in various ways.

As is clear from the above explanation, according to the present invention, the presence or absence of a fault in the input circuit is immediately detected, the validity of information input is constantly determined, and processing according to the information input is performed only when this is valid. Therefore, the reliability of digital circuits that use contact outputs as input is greatly improved, and great effects can be obtained in various electronic devices.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the processor.
FIG. 3 is a block diagram showing another embodiment. rl, rl ₁ , rl ₂ ...Contact, B, _B1 , _B2 ...Single pole,
C, C ₁ , C ₂ ... other pole, F, F ₁ , F ₂ ... closed pole,
IN...Inverter, CPU...Processor,
X ₁ , X ₂ ... Information input, Y ... Confirmation input, Z ...
Confirmation output, FF...FFC (flip-flop circuit: signal source), CP...control pulse.

Claims (1)

[Scope of utility model registration request] an inverter that provides an inverted output to one pole of the contact;
a signal source that provides alternately inverted confirmation outputs to the input of the inverter; a signal source that uses the inverting output of the inverter and the signal from the other pole of the contact as a confirmation input and information input; A contact input circuit comprising a processor that determines the validity of the information input based on the situation.