JPH0216075A - Abnormality detection circuit - Google Patents

Abstract

PURPOSE:To ensure the detection of a clock pulse abnormality to inhibit the malfunction in outputting a power source remote signal by mounting a clock abnormality detection means for inputted a clock pulse therein to detect the abnormality and a control means for turning a power source remote signal OFF according to the output from the detection means. CONSTITUTION:In an abnormality detection circuit for detecting the abnormality of a motor or the like used for traveling a head pin or a carridge in a wire dot printer, a one-shot multivibrator 28 is used as a clock abnormality detection means. If the occurrence of abnormality in the clock pulse outputted from a clock pulse generation means 21 eliminates the waveform of the clock pulse, after a one-shot time constant elapses thereafter the output of the one-shot multivibrator 28 is reduced to make an AND circuit 27 stop the output of a power source remote signal. A counter 26 functions for detecting the abnormality caused by the failure and the like of a control circuit 22 or a transistor 23.

Description

[Detailed Description of the Invention] [Summary] Regarding the abnormality detection circuit provided in the head bin of a wire dot printer or the motor used to move the carriage, the circuit detects the stoppage of clock pulses and turns the power supply remote signal to ON.
The clock abnormality detection means detects an abnormality in the clock pulse by inputting the clock pulse from the clock pulse generation means that outputs the clock pulse to the control circuit and the counter; The apparatus is equipped with power remote signal control means for turning off the power remote signal in accordance with the output of the abnormality detection means.

(Industrial Application Field) The present invention relates to an abnormality detection circuit provided in a motor used for moving a head bin or a carriage of a wire dot printer.

[Conventional technology]

A conventional abnormality detection circuit consists of a circuit that detects that current is flowing through a load, and a circuit that detects that the output continues longer than in a normal case.

For example, as shown in FIG. 4, a control circuit 2 that inputs clock pulses from a pulse generator 1 is connected to the base B side of a transistor 3, its emitter E side is grounded, and its collector C side is connected to a coil 4. Connected. The ends of the coils 4 are each connected in parallel to an energization detection circuit 5, and the end of the coil 4 on the side opposite to the transistor connection side is connected to a power input line 6. A clock pulse is input from the pulse generator 1 to the output side of the energization detection circuit 5, and a counter 7 for inputting the energization detection result is connected, and the output side of the counter 7 is connected to the input side of the AND circuit 8. Connect the output side of the power supply 1 to the power supply 1 via the power supply remote signal output line 9z.
Connect to the 0 side.

This circuit detects the potential difference between each terminal on the power supply side and the transistor side of the coil 4, converts it to a TTL (transistor transistor logic) level for the counter 7, and outputs it.

The counter 7 monitors whether the power is being energized for longer than the normal energization time.

Through this monitoring, an abnormality can be detected in case of destruction of the control circuit 2 or transistor 3, and the power supply remote signal can be turned off.
It can be F.

(Problems to be Solved by the Invention) In the conventional abnormality detection circuit described above, when the clock pulse input to the control circuit 2 or the counter 7 stops, the control circuit 2 may malfunction or the transistor 3 may turn off.
Even if it becomes N, the counter 7 cannot measure the energization time and cannot detect an abnormality, so the power supply remote signal cannot be turned OFF, and in the worst case, the load will burn out. There was a problem.

The present invention has been made in view of the above problems, and the technical problem set to solve the problem is to detect the stop of the clock pulse and turn off the power remote signal. An object of the present invention is to provide an abnormality detection circuit that provides a

[Means to solve the problem]

As a specific means for solving the above problems, the present invention provides a control circuit 12 for inputting clock pulses from a clock pulse generation means 11, and a control circuit 12 for configuring an abnormality detection circuit, as shown in FIG. A transistor 13 which connects the circuit 12 to the base B side and connects the emitter E side to the ground G, a coil 14 which is connected between the collector C side of the transistor 13 and the power supply 10, and which is connected to both ends of the coil 14. , a energization detection circuit 15 connected to the ground G by VC, a counter 16 to which the output of the energization detection circuit 15 is input and a clock pulse from the clock pulse generation means 11, and a control circuit 12 or A: Preventing the power supply remote signal from being output when an abnormality in the transistor 13 is detected
an ND circuit 17; a clock abnormality detection means 18 that receives clock pulses from the clock pulse generation means 11 which outputs clock pulses to the control circuit 12 and the counter 16 and detects an abnormality in the clock pulses; It is equipped with a power remote signal control means 19 that turns off the power remote signal by outputting it.

(Function) With the above configuration, the present invention has the clock pulse generating means 11
When an abnormality occurs such as the clock pulses to be output from the clock stop, the clock abnormality detection means 18 detects the abnormality, and the power remote signal control means 19 forcibly turns off the power remote signal. Prevent malfunction.

(Embodiment) Hereinafter, as an embodiment of the present invention, a case where a one-shot multivibrator is used as the clock abnormality detection means and an AND circuit is used as the power supply remote signal control means will be illustrated and explained.

As shown in FIG. 2, a control circuit 22 receives clock pulses from a clock pulse generating means 21,
2 connected to the base B side and the ground G connected to the emitter E side, a coil 24 connected between the collector C side of the transistor 23 and the power supply 10, and both ends of the coil 24 connected, An energization detection circuit 25 connected to ground G, a counter 26 to which the output of the energization detection circuit 25 is input and a clock pulse from the clock pulse generation means 21 is input;
control circuit 22 or transistor 2 by inputting the output of
Clock pulses are input from the AND circuit 27 which prevents the power supply remote signal from being output when an abnormality in step 3 is detected, and the clock pulse generating means 21 which outputs clock pulses to the control circuit 22 and the counter 26. a retriggerable one-shot multivibrator 28 as a clock abnormality detection means for detecting;
The output side of the one-shot multivibrator 28 is A
It is connected to the input side of the ND circuit 27 so that the AND circuit 27 can also be used as power remote signal control means and can turn off the power remote signal when an abnormality in the clock pulse is detected.

The energization detection circuit 25 connects the base B side of the transistor 32 to the connection point between the collector C side of the transistor 23 and the coil 24 via the resistor 31, and connects the emitter E of the transistor 32 to the connection point on the power supply side of the coil 24. The collector C side of the transistor 32 is connected to the ground G through a resistor 33 and a Zener diode 34 in series.

The input side of the counter 26 is connected to the connection point between the resistor 33 and the Zener diode 34.

On the input side of the AND circuit 27, the output of the counter 26 and
The output of the one-shot multivibrator 28 is connected to a control line 29 through which a control signal is input.

Using the embodiment configured in this way, if an abnormality occurs in the clock pulse output from the clock pulse generating means 21, the one-shot After the time determined by the time constant has elapsed, the output of the one-shot multivibrator 28 drops, and the output of the AND circuit 27, ie, the power supply remote signal, ceases to be output.

In such an embodiment, when an abnormality is detected due to damage to the control circuit 22 or the transistor 23, the counter 2
6 functions, and the one-shot multivibrator 28 is activated for abnormality detection caused by the clock pulse generating means 21.
functions, and the power supply remote signal can be turned off via the AND circuit 27.

〔Effect of the invention〕

As described above, the present invention includes a clock abnormality detecting means 18 which detects an abnormality by inputting the clock pulses of the clock pulse generating means 11 which are outputted to the control circuit 12 and the counter 16, and a power source using the output of the clock abnormality detecting means 18. By including the power supply remote signal control means 19 for turning off the remote signal, an abnormality in the clock pulse can be reliably detected and the control circuit 12 or counter 16
It is possible to prevent the output of unnecessary power supply remote signals due to malfunction of the system, and it is possible to realize an inexpensive circuit that can reliably detect abnormalities.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an abnormality detection circuit according to the present invention. FIG. 2 is a block diagram showing an abnormality detection circuit according to an embodiment. FIG. Timing Chart FIG. 4 is a configuration diagram showing a conventional abnormality detection circuit. 11... Clock pulse generation means 12... Control circuit 13... Transistor 14... Coil 15... Energization detection circuit 16... Counter 17... AND circuit 18... Clock abnormality detection means 19...Power supply remote signal control means

Claims (1)

[Scope of Claims] Clock abnormality detection means (18) that detects abnormalities in clock pulses by inputting clock pulses from the clock pulse generation means (11) that outputs clock pulses to the control circuit (12) and the counter (16). and power remote signal control means (1) which turns off the power remote signal by the output of the clock abnormality detection means (18).
9) An abnormality detection circuit comprising: