JP3153593B2 - Safety device for numerical control machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a numerical control machine having a positioning loop which is numerically controlled, and alarm detecting means which can output an alarm when a power source of the positioning loop is cut off. .

[0002]

2. Description of the Related Art In Europe, in order to ensure the safety of operators, it is required by law to shut down the machine safely when stepping on the safety mat or stepping on the safety mat to approach the machine. It is common to install a safety device in such a machine. Therefore, conventionally, it has been general to install the above-described safety device, detect that a person has approached the machine, and stop the machine by software.

However, if the safety is reconsidered, 100% stoppage is not always ensured due to software bugs, semiconductor failures, and the like. That is, in the numerical control device, even when the numerical control system indicates the stop state, the positioning system, the servo amplifier, and the like may fail and the motor may run away.

Therefore, in order to improve safety, it is necessary to shut off the power source by a relay having mechanical contacts and detect a failure of the relay.

On the other hand, if the power source is cut off by a positioning device constituting a speed loop such as the X and Y axes of a punch press, the balance of the loop is lost, an alarm is generated, and the power is cut off. Was impossible. Further, when the power line is cut off, a disconnection detection error occurs, so that an error is generated in the servo amplifier and an alarm is generated. When an alarm is generated, operations such as resetting and returning to the origin must be performed again from the beginning, and subsequent processing is difficult.

Therefore, conventionally, the servo system has been stopped by software, and the power source of an open-loop motor such as a normal induction motor or solenoid has been cut off.

[0007]

As described above, in the conventional safety device for a numerical control machine, an alarm is generated when the power source of the servo system is shut off. Only output a stop command, and there was a problem with safety. Further, if the power source is forcibly shut off, an alarm is generated, so that the subsequent processing is difficult, and there is a problem in that a part being processed becomes defective.

Accordingly, an object of the present invention is to provide a safety device for a numerical control machine which is excellent in safety, operability and productivity.

[0009]

According to the present invention, there is provided a safety device for a numerical control machine according to the present invention.

[0010]

With the safety device for a numerical control machine of the present invention having the above-described configuration, an alarm is not generated even if the power source is cut off by the positioning system forming the servo loop, and the troublesome operation of restoring is performed. Even without it, it can be stopped reliably.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a safety device for a numerical control machine according to one embodiment of the present invention, and FIGS. 2 to 5 are circuit diagrams showing details of each part.

In FIG. 1, a condition input section 1 is a section for inputting a detection signal (danger state detection signal) of a light ware or a safety mat. The signal input to the condition input unit 1 is output to the input distribution unit 2. The input distribution unit 2 receives a dangerous state detection signal and simultaneously outputs the signal to the hardware processing unit 3 and the high-speed processing unit 4.

The hardware processing unit 3 generates a power-off condition using hardware such as a relay, and outputs the power-off condition to the error detection unit 5. The error detection unit 5 performs error detection while feeding back the signal of the output unit 6. When an error occurs, a power cutoff signal is output to the output unit 6. The output unit 6 outputs a power cutoff signal to the power cutoff unit 7. The time required so far is defined as T1. An alarm detector 9 is provided in the servo amplifier 8, and normally detects that the power is interrupted by the power interrupter 7 and outputs an alarm.

On the other hand, the high-speed processing unit 4 processes logic similar to that of the hardware processing unit 3 at a higher speed than the signal output from the input distribution unit 2, and a time T2 shorter than the processing time T1 (T2 <T1). Informs the alarm detecting section 9 of the servo amplifier 8 that the power is cut off, and instructs in advance to reset the detection signal for the power cut off. Thus, the alarm detection unit 9 can reset the power supply so that an alarm is not generated even when the power is cut off, by watching the signal output from the high-speed processing unit 4.

In FIG. 2, a terminal A is connected to a hardware processing unit 3. Terminal B is connected to high-speed processing unit 4. In FIG. 4, R1 to R3 indicate safety relays. In FIG. 5, a terminal C is connected to the high-speed processing unit 4.
As described above, each unit shown in FIG. 1 can be appropriately configured by an electric circuit. However, the present invention is not limited to the circuits shown in FIG. 2 to FIG. Time T2,
What is necessary is just to be comprised so that T2 <T1. For example, the power cutoff unit 7 may be arranged on the input side of the servo amplifier 8 instead of being arranged on the output side.

As described above, in this embodiment, various input signals are divided into a relay process and a software process, and the information is transmitted to the alarm detecting unit 9 before the power line is finally cut off by the hardware process. Does not occur, no alarm is generated even if the power line of the servomotor M is cut off, and it is not necessary to reset or return to origin after safety stop.

The present invention is not limited to the above-described embodiment, but can be implemented in an appropriate mode by making appropriate design changes.

[0018]

As described above, the present invention is a safety device for a numerical control machine as described in the claims. Therefore, even if the power source is cut off by the positioning system constituting the servo loop, an alarm will be generated. In addition, it is possible to surely stop the apparatus without performing a troublesome operation for returning again.

[Brief description of the drawings]

FIG. 1 is a block diagram of a safety device of a numerical control machine according to one embodiment of the present invention.

FIG. 2 is a circuit diagram showing details of a condition input unit and an input distribution unit.

FIG. 3 is a circuit diagram showing details of a hardware processing unit and a high-speed processing unit.

FIG. 4 is a circuit diagram showing details of an output unit.

FIG. 5 is a circuit diagram showing details of a power cutoff unit.

[Description of Signs] 1 Condition input unit 2 Input distribution unit 3 Hardware processing unit 4 High-speed processing unit 5 Error detection unit 6 Output unit 7 Power cutoff unit 8 Servo amplifier 9 Alarm detection unit

Claims (1)

(57) [Claims] 1. A danger state is detected in a safety device for a numerical control machine, comprising: a positioning loop to be numerically controlled; and alarm detection means for outputting an alarm by detecting that a power source of the positioning loop has been cut off. And a power cutoff means for inputting a detection signal of the sensor and shutting off a power source of the positioning loop; and inputting a detection signal of the sensor and acting on the alarm detection means before the operation of the power cutoff means. And a signal reset means for ignoring a detection signal indicating that the power source has been cut off, and a safety device for a numerical control machine.