JPS61265918A - Logic circuit - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution while attaining contactless configuration and fail safe by deciding whether or not the frequency of output signal of a multiplier circuit is a prescribed frequency and generating a logical output based on the decided result. CONSTITUTION:An output is given from a decision circuit 18 with the input condition of logical output '1' and logical output '1' is obtained. No output is supplied from the decision circuit 18 with the input condition corresponding to logical output '0' or circuit fault and logical output '0' is outputted. That is, the frequency f1 of the signal inputted from a frequency division circuit 12 is multiplied by a ratio L being a constant write signal fW inputted to a multiplier circuit 17 to a multiple rate signal fR, a signal having the multiplied frequency f1 is outputted from the multiplication circuit 17 is outputted and compared with a prescribed frequency f0 at the circuit 18. When the relation of f1=f0 exists, the logical output of the circuit 18 goes to '1', a relay 19 is excited and when f1not equal to f0, the logical output goes to '0' and the relay 19 is not excited.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a non-contact logic circuit that does not use relays.

(Prior Art) When a large amount of input information is obtained and a load is controlled by combining the input information, it is common to control the load by outputting a logical value according to the conditions of a group of input information using a logic circuit.

For example, new transportation systems use rubber-tired vehicles, so conventional track circuit methods cannot be used for train detection. Therefore, in the case of such a new transportation system, conventionally, a logic circuit for train detection is constructed using a large number of relays, and a group of these relays is operated based on train position information to detect the presence or absence of a train. There is.

An example of such a train detection method is shown in FIGS. 2 and 3.

In the figure, reference numeral 1 indicates a train, which oscillates a signal r from its front head and a signal f2 from its back head. IT, 3T, 5T...
is the induction loop provided for each section of the train track.

2 is a signal source that transmits the reference signal rcn, 3 is a guidance route 1
f, which receives the reference signal rc11 via 3T; 1. Receivers 4 and 5 each send signals f, ,f, through induction loops 3T
f, receiver, and f2 receiver, respectively. FCHR, F+R, FzR are each receiver 3
Relay F t is a relay operated by a signal from ~5.
R.

F and R are energized when train 1 enters the area of induction loop 3T and signals f,, f2 are received via loop 3T, and relay FcHR is normally energized by reference signal fCM, but When signal f or f2 is received via the induction loop 3T due to the entry of signal fcH, the reference signal fcH is suppressed and becomes non-excited. Note that although the receivers 3 to 5 and the relays FCNR, FtR, and FzR are not shown, they are provided for each induction loop. Train detection in each section is carried out by each relay Fc, R, FAR operating as described above.
, FzR are used to configure a logic circuit as shown in Figure 2, and each contact is opened or closed depending on the presence or absence of train 1 in each section, and the train detection relay is energized or de-energized. is established to detect the presence or absence of a train in each section. Furthermore, Figure 2 shows guidance route 1.
3TFzr, 3TF+r, 3TFc, , r are the contacts of the relays FCHR, F+R, FtR connected to the induction loop 13T, and 5TFzr is the relay F connected to the induction loop 5T.
, R contacts, I T F Ir are the contacts of the relay FIR which connects to the inductive loop IT. In addition, 3TR indicates a train detection relay in the area of the induction loop 3T, and 3TR
is a contact point of the relay 3TR. Furthermore, 17r.

5Tr indicates the contact point of the train detection relay in the area of the induction loop IT and 5T, respectively. B indicates the positive side of the power supply, and C indicates a grounding example.

<Problems to be solved by the invention> However, when configuring a logic circuit using relays as in the past, as the number of input information increases, the number of relays increases, resulting in extremely multiple circuit configurations, and the durability is poor. There are also problems with sexuality. To solve this problem, it would be possible to use a non-contact type logic circuit such as TTL, but in this case, fail-safe performance, which is most important for railway signals that require a high degree of safety, cannot be ensured. There's a problem.

Therefore, the present invention was made in view of the above-mentioned circumstances.
The purpose is to provide a fail-safe logic circuit that is non-contact type and has a simple circuit configuration.

Means for Solving the Problems> For this reason, the present invention includes a ROM that stores a frequency division ratio corresponding to input information, a frequency division circuit that divides an input signal according to the frequency division ratio output from the ROM, and A multiplier circuit that multiplies and outputs the frequency of the output signal of the frequency divider circuit, and a multiplier signal generator that receives the same information as the manual information of the ROM and outputs a multiplier signal of the multiplier circuit in accordance with the input information. The present invention includes a circuit and a determination circuit that determines whether the frequency of the output signal of the multiplier circuit is a predetermined frequency or not and generates a logical output based on the determination result.

As a result, when the input condition is such that the logic output is "1", when the output signal frequency of the frequency divider circuit is multiplied by the multiplication rate signal of the multiplication rate signal forming circuit, the predetermined frequency is reached, and the output from the determination circuit is A logic output of "1" is obtained. In addition, when the input condition corresponds to the logic output "0" or in the event of a circuit failure, the output signal from the multiplier circuit when multiplied becomes a frequency other than the predetermined frequency, and there is no output from the judgment circuit, and a logic output "0" is output. be done.

<Example> An example of the present invention will be described in detail below with reference to FIG.

In FIG. 1, 11 is a ROM that stores a frequency division ratio according to human input information, and 12 is a frequency divider that divides the frequency of the signal input from the signal source 13 by the frequency division ratio output from the ROMLL and outputs the frequency. It is a circuit. 14 is a multiplication rate signal forming circuit which receives the same input information as the ROM 11 and outputs a multiplication rate signal according to this input information. The multiplication rate signal forming circuit 14 specifically includes a ROM 15 and a frequency division circuit 16. The ROM 15 stores a frequency division rate according to input information, and the frequency division circuit 16 is configured to perform the aforementioned frequency division. circuit 1
2 is frequency-divided by the frequency division ratio output from the ROM 15 and outputted, and this output is output as a multiplication ratio signal.

17 is a multiplier circuit that multiplies the frequency of the output signal from the frequency divider circuit 12 based on a multiplier signal from the multiplier signal forming circuit 14.

This multiplier circuit 17 has a configuration similar to that disclosed in Japanese Patent Laid-Open No. 58-143605, in which an input signal is written into the RAM using a write signal, and then the input signal stored in the RAM is read using a read signal. At this time, the input signal is multiplied by the ratio of the periods of the write signal and the read signal.

Reference numeral 18 denotes a determination circuit that determines whether the frequency of the output signal of the multiplier circuit 17 is a predetermined frequency set in advance or not, and issues a logical output based on the determination result. Specifically, for example, only a signal of a predetermined frequency is passed through. It is composed of a filter and a Schmitt trigger circuit, and only when the output signal of the multiplier circuit 18 has a predetermined frequency, the Schmitt trigger circuit is triggered and a logic output of "1" is output. Reference numeral 19 designates, for example, a train detection relay as a load whose drive is controlled based on the output of the determination circuit 18.

Next, the operation will be explained.

When input information, for example, information corresponding to the opening/closing conditions of each contact shown in FIG. 2, is given to the ROMII, the frequency division ratio N corresponding to this information is retrieved and output to the frequency division circuit. Then, the frequency f of the signal input to the frequency dividing circuit 12 is divided by the frequency division ratio N, (=f.

/N) is input from the frequency divider circuit 12 to the multiplier circuit 17.

At the same time, ROM1 of the multiplication rate signal forming circuit 14
5 is also given the same input information, and the frequency division ratio M is determined accordingly. Then, a multiplication factor signal, that is, a signal of frequency f* (=fs/M) is input from the frequency dividing circuit 16 to the multiplication circuit 17.

On the other hand, a constant write signal f1 is manually input to the multiplier circuit 17, and this write signal f8 and the multiplication rate signal fll
The frequency f of the signal input from the frequency dividing circuit 12 is multiplied by the ratio L (= f * / f w), and the frequency f of the signal input from the frequency dividing circuit 12 is multiplied by
This multiplied frequency f L (= f tX L)
A signal is output and compared with a predetermined frequency f0 in the determination circuit 18. Then, if fL=f, the logic output of the determination circuit 18 becomes "1", and the relay 19 is energized so that f, ≠
If it is f0, the logic output is "0" and the relay 19 is not excited.

That is, only when the condition for exciting the relay 19 is input,
The output signal frequency f of the multiplier circuit 17 based on f, and fR,
The relay 19 is excited by setting the relationship between f and fl so that f,=f.

Furthermore, when a condition for not energizing the relay 19 is input, the relay 19 is not energized by setting the relationship between fi and fR so that f,≠fo. Furthermore, ROM
If II, 15 fails, then fL in the relationship between fR and fR.
Since =f0 does not hold and the logical output becomes 0'', it can be made fail-safe.

In this way, the circuit configuration is extremely simple compared to a logic circuit composed of relays, and since there is no contact, the durability can be made semi-permanent. Moreover, in the event of a failure, the output will be “O”.
”As it is fail-safe, it is extremely effective in terms of safety measures.

<Effects of the Invention> As described above, according to the present invention, a logic circuit can be made contactless and can be configured in a fail-safe manner.
This has the effect that the circuit configuration can be significantly simplified, and durability and safety can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
Figure 3 shows an example of application of a conventional logic circuit using relays.
The figure shows a circuit diagram of the same relay logic circuit. 11... ROM 12... Frequency divider circuit 13.
... Signal source 14 ... Multiplication rate signal forming circuit 17 ...
・Multiplier circuit 18...judgment circuit

Claims (1)

[Claims] A ROM that stores a frequency division ratio corresponding to input information, and the RO
A frequency divider circuit that divides the input signal according to the frequency division ratio output by M, a multiplier circuit that multiplies and outputs the frequency of the output signal of the frequency divider circuit, and the same information as the input information of the ROM is input. A multiplication factor signal forming circuit that outputs a multiplication factor signal of the multiplier circuit in accordance with the input information, and a determination device that determines whether the frequency of the output signal of the multiplier circuit is a predetermined frequency or not and generates a logical output based on this determination result. A logic circuit characterized by comprising a circuit.