JPH064263Y2 - Electromagnetic induction type detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Use) The present invention relates to an improvement of an electromagnetic induction detector adopting a DSCG system.

(Prior Art) In recent years, for example, for detecting the position of a movable object of a numerical control device, a DSCG type electromagnetic induction type detector is often used. In this DSCG electromagnetic induction type detector, a digital triangular wave signal indicating the position of a movable object, that is, a digital sin signal or cos signal is input to each of the two windings on the primary side, so that the windings on the secondary side An analog signal corresponding to the relative position of the movable object is output. FIG. 4 shows a schematic structure of a position detecting device using this type of detector. This device generates a sin signal and a cos signal from a digital triangular wave generator 2 and supplies them to the detector 1, The error voltage E output from the detector 1 is passed through the low-pass filter 3, rectified and smoothed by the synchronous rectification circuit 4 and the smoothing circuit 5, and then converted into a pulse signal by the voltage frequency conversion circuit (V / F) 7. The lever signal is output as a detection pulse. Further, the DC voltage output from the smoothing circuit 6 is encoded and output by the code detector 8, and this code is fed back to the digital triangular wave generator 2 together with the detection pulse output from the V / F 7.

Reference numeral 5 is a synchronous rectification signal generator that generates a signal for synchronous rectification based on the triangular wave signal generated from the digital triangular wave generator 2.

With such a configuration, for example, when a signal sinα · sinωt is generated as a sin signal and a signal −cosα · sinωt is generated as a cos signal and supplied to the detector 1, the detector 1 outputs the following signal. Error voltage E is output.

E = sin α · cos θ · sin ωt −cos α · cos θ · sin ωt = sin (α−θ) sin ωt where θ is the angle or displacement of the movable object.

The error voltage E is rectified and smoothed, converted into a pulse signal having a frequency corresponding to the voltage level, and fed back to the digital triangular wave generator 2. As a result, in the digital triangular wave generator 2, the error voltage E becomes E = Vary α so that it becomes zero. That is, as shown in FIG.
The pulse widths of the n signal and the cos signal are changed so that the error voltage E becomes E = 0. The value of α when E = 0 is output as a signal indicating the position of the movable object. Thus, for example, the position of the manipulator of the numerical control device is detected.

However, in these various conventional devices, when the winding of the electromagnetic induction type detector 1 is broken for some reason, an abnormal detection pulse is generated and the device runs out of control, which causes damage to the mechanism such as the movable part. May invite you. Therefore, conventionally, a control unit of a device that receives the above-mentioned detection pulse and performs various controls, for example, a numerical control device, is provided with a function of counting up the detection pulse and detecting disconnection from the number, for example. We try to prevent runaways. However, in such a conventional configuration, the control content is complicated because the dedicated program for the wire breakage detection must be created and prepared in the numerical controller, and the wire breakage occurs because the detection pulse does not occur depending on the wire breakage location. In some cases, it could not be detected, and it was not possible to reliably detect the occurrence of disconnection.

(Problems to be solved by the invention) As described above, since the conventional electromagnetic induction type detector does not have the function of detecting the disconnection of the winding wire, the detection of the disconnection can be performed by, for example, the control unit of the numerical controller. This has the problem that the control section is complicated and the disconnection cannot be detected with certainty.Therefore, the present invention pays attention to this point and detects the disconnection of the winding wire with confidence in the detector. All can be detected reliably and with a simple configuration, which reduces the burden on the side that uses the detection results of the detector and contributes to improved reliability,
Moreover, even when the output error voltage of the secondary winding is controlled to be zero, an electromagnetic induction type detector capable of reliably detecting disconnection of the secondary winding with high sensitivity is provided. It is a thing.

[Structure of the Invention] (Means for Solving Problems) The present invention focuses on the fact that when the windings of both the primary side and the secondary side are disconnected, the circuit resistance increases and the voltage across the primary side increases. First for each winding on the secondary side and each winding on the secondary side
And a second disconnection alarm circuit, the first disconnection alarm circuit monitors the voltage level of the digital triangular wave signal applied to the two windings on the primary side, and this voltage level is preset to a predetermined threshold. A disconnection alarm signal is output when the value exceeds the value, and a DC voltage for disconnection detection is applied to the secondary winding by the second disconnection alarm circuit to monitor the applied voltage level. The disconnection alarm signal is output when the voltage level exceeds a preset threshold value.

(Operation) As a result, the electromagnetic induction type detector itself can detect the disconnection of each winding, which eliminates the need for a detection function on the side using the detection result, which simplifies the configuration.
In addition, since any disconnection will be detected without exception,
The measure against disconnection can always be surely executed, and thereby the reliability of the device can be improved. Furthermore, in the present invention, a DC voltage for disconnection detection is applied to the secondary winding,
By monitoring the DC voltage level, disconnection of the secondary winding is detected. Therefore, even if the secondary side winding is used in a device that variably controls the digital triangular wave signal supplied to the primary side winding so that the analog error voltage level output from the secondary side becomes zero, The disconnection of the secondary winding can be reliably detected with high sensitivity regardless of the analog error voltage level output from the line.

(Embodiment) FIG. 1 shows the structure of an electromagnetic induction type detector according to an embodiment of the present invention. Reference numerals 11 and 12 denote two primary windings, and 13 denotes a secondary winding. The winding is shown.

First, the respective windings 11 and 12 on the primary side are provided with comparators 14 and 16, respectively. These co-operators 1
4 and 16 are sin applied to the windings 11 and 12, respectively.
The voltages V1 and V2 of the signal and cos signal are introduced to the non-inverting input terminal (+), and the voltages V1 and V2 are supplied to the power sources 15 and 17,
Compared to the threshold voltage _{V B1, V B2} which is set by said applied voltage V1, V2 is the threshold voltage _V B1, V
_The alarm signals D1 and D2 are output when _B2 or more. On the other hand, the secondary side winding 13 is provided with a voltage supply circuit 23 and a comparator 20 for detecting disconnection. The voltage supply circuit 22 includes a DC power supply 18, a current limiting resistor 19 and a capacitor 22, and applies a DC voltage for detecting disconnection to the winding 13. The capacitor 22 prevents the DC voltage V3 for detecting the disconnection from being output to the output terminal of the error voltage E. The comparator 20 is
The voltage V3 applied to the winding 13 by the voltage supply circuit 23 is introduced to the non-inverting input terminal (+), and this voltage V3 is compared with a threshold voltage V _B3 preset by the power supply 21 and The warning signal D3 is generated when the applied voltage V3 is equal to or higher than the threshold voltage _VB3 .

With such a configuration, it is assumed that the sin signal and c
If the winding 11 on the primary side is disconnected during the application of the os signal, the voltage V1 of the sin signal applied to the winding 11 increases and the threshold voltage V _{B1 of the} power supply 15 as shown in FIG.
As a result, the alarm signal D is output from the comparator 14 as a result.
1 is output. If the winding 12 is broken,
As shown in FIG. 2, the voltage of the cos signal becomes equal to or higher than the threshold value V _B2, and the comparator 16 outputs the alarm signal D2. Two-dot chain lines a and b in FIG. 2 are applied voltages V1 and V2 in a normal state where no disconnection occurs. On the other hand, when the winding 13 on the secondary side is broken, the line resistance of the winding 13 increases, and accordingly, the power supply circuit 23
The DC voltage V3 applied to the winding 13 from the above increases to a threshold value V _B3 or more as shown in FIGS. 3C to 3D, which causes the comparator 20 to output the alarm signal D3.
Is output.

Therefore, for example, in a numerical controller operating based on the detection result of the electromagnetic induction type detector, the drive control of the movable part such as the manipulator is stopped at the time when any one of the alarm signals D1 to D3 is generated. If the movable part is set to be locked, runaway of the movable part can be surely prevented.

As described above, according to the present embodiment, the electromagnetic induction type detector is provided with a circuit for detecting a disconnection and generating an alarm by monitoring the applied voltage to the windings 11, 12, 13 and, therefore, this detector A numerical controller or the like utilizing the detection output can surely prevent runaway of the movable part without providing a wire breakage detecting means, thereby simplifying the configuration of the controller and improving reliability. Further, according to the present embodiment, in order to detect the disconnection of the secondary winding 13, the secondary winding 13
Of the secondary winding 13 instead of detecting the output error voltage of
A disconnection detection is performed by applying a DC voltage for disconnection detection to and monitoring the DC voltage level. Therefore, as in the position detecting device of the present embodiment, the error voltage E output from the secondary winding 13 is set to 0 so that the error voltage E becomes zero.
Even when feedback control is performed on the pulse width of the signal and the cos signal, the disconnection of the secondary winding is always detected with high sensitivity regardless of the output error voltage level of the secondary winding 13. You can

The present invention is not limited to the above embodiment. For example, in the above embodiment, the applied voltages V1 and V2 of the primary windings 11 and 12 are individually compared with the threshold values V _B1 and V _B2 by the comparators 14 and 16, respectively. V2 may be wired-or and its output voltage may be compared with a threshold value. In addition, the configurations of the first and second alarm circuits can be variously modified and implemented without departing from the scope of the present invention.

[Effects of the Invention] As described above in detail, according to the present invention, the first and second disconnection alarm circuits are provided in each of the primary winding and the secondary winding, and the first disconnection alarm circuit is provided. , Monitoring the voltage level of the digital triangular wave signal applied to the two windings on the primary side, and outputting a disconnection alarm signal when this voltage level exceeds a preset threshold value,
Further, the second disconnection alarm circuit applies a DC voltage for detecting disconnection to the secondary winding to monitor the applied voltage level, and the voltage level becomes equal to or higher than a predetermined threshold value set in advance. If a disconnection alarm signal is output in the event of a failure, the detector itself can detect the disconnection of the winding wire reliably and with a simple configuration, thereby reducing the burden on the side using the detection results of the detector. In addition, it contributes to the improvement of reliability, and even when the output error voltage of the secondary winding is controlled to be zero, the disconnection of the secondary winding can be reliably detected with high sensitivity. An inductive detector can be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an electromagnetic induction type detector according to an embodiment of the present invention, FIGS. 2 and 3 are signal waveform diagrams used for explaining the operation of the detector, and FIG. 4 is a conventional electromagnetic wave type. Circuit block diagram of position detection device using inductive type detector,
FIG. 5 is a signal waveform diagram used for explaining the operation of the apparatus. 1 ... Electromagnetic induction type detector, 2 ... Digital triangular wave generator, 3 ... Low-pass filter, 4 ... Synchronous rectification circuit, 5
...... Synchronous rectification signal generator, 6 …… Smoothing circuit, 7 …… Voltage frequency converter (V / F), 8 …… Sign detector, 11,1
2 ... Primary side winding, 13 ... Secondary side winding, 14, 1
6, 20 ... Comparator, 15, 17, 21 ... Power supply for generating threshold voltage, 18 ... DC power supply, 19 ... Current limiting resistor, 22 ... Capacitor, 23 ... Voltage supply for detecting disconnection Circuit, V1, V2, V3 ... Applied voltage to windings, V _B1 , V _B2 , V _B3 ... Threshold voltage, D1,
D2, D3 ... Alarm signal.

Claims (1)

[Scope of utility model registration request] 1. A digital triangular wave signal representing the positions of two movable objects is applied to each of the two windings on the primary side of the electromagnetic induction type detector, and output from the winding on the secondary side of the electromagnetic induction type detector. The electromagnetic induction type detector used in the position detecting device for monitoring the voltage level of the analog error signal of each digital triangular wave signal and variably controlling the digital triangular wave signal so that the voltage level becomes zero. In the above, the voltage level of the digital triangular wave signal applied to the two windings on the primary side is monitored, and when the voltage level becomes equal to or higher than a predetermined threshold value set in advance, disconnection of the primary side winding is performed. A first disconnection alarm circuit that outputs an alarm signal, and a DC voltage for detecting disconnection is applied to the secondary winding to monitor the applied voltage level, and the voltage level is preset to a predetermined threshold. Less than value Inductive detector characterized by comprising a second break alarm circuit for outputting a disconnection alarm signal of the secondary winding if it becomes.