CN209928002U - Encoder broken line detection circuit - Google Patents
Encoder broken line detection circuit Download PDFInfo
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- CN209928002U CN209928002U CN201920258608.2U CN201920258608U CN209928002U CN 209928002 U CN209928002 U CN 209928002U CN 201920258608 U CN201920258608 U CN 201920258608U CN 209928002 U CN209928002 U CN 209928002U
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Abstract
The utility model discloses an encoder broken string detection circuitry, including voltage conversion circuit, comparison circuit and decision circuit. The voltage conversion circuit is connected with the differential signal output by the encoder, performs bias voltage and offset compensation on the differential signal, converts the differential signal into a single-ended signal and outputs the single-ended signal; the comparison circuit is connected with the voltage conversion circuit, and compares the single-ended signal output by the comparison circuit with the disconnection detection reference voltage and outputs a comparison result; the judging circuit is connected with the comparing circuit, carries out logic judgment on the output comparison result and outputs a detection result. The utility model adopts the resistor, the capacitor and the comparator to complete the detection of the broken line of the encoder; the disconnection detection can be carried out when the encoder is static and in standby; the condition of any one of three phases of the encoder is broken can be detected; the method can detect the error of the differential voltage bias and the phase deviation of the encoder as usual.
Description
Technical Field
The utility model belongs to encoder detection circuitry field especially relates to an encoder broken string detection circuitry.
Background
An Encoder (Encoder) is a device for converting an angle signal into a digital signal, and the Encoder is divided into an absolute Encoder and an incremental Encoder, and the incremental Encoder is widely applied by the characteristics of reliability, precision, simplicity, easiness in use and the like. The incremental encoder transmits medium signals to differential voltage, and relies on the anti-interference transmission information of the differential voltage, and the absolute encoder uses one phase or two phases to detect. In the actual use process, the situations of disconnection of a connector of the encoder, poor contact, unreliable cables (such as disconnection of partial cables, short circuit of partial cables and the like) and the like exist, and when the situations occur in industrial production, the working electric appliances, equipment and even local power grids are damaged, dangerous accidents occur, and the life and property safety of users is seriously threatened.
In the prior art, two modes of software detection and hardware detection are generally used for detecting the disconnection of an encoder. The software detection needs to finish the wire break detection by means of the movement of the encoder carrier, when the motor is in a static state or a standby state or the motor moves slowly, the wire break detection of the encoder cannot be finished, but in the actual use process, the wire break detection mostly needs to finish the detection in the static state of the motor. When any + or-signal in the encoder A, B, C phase is disconnected (broken), the software can still acquire the pulse signal of the encoder, and the software cannot or is difficult to judge whether a certain path of the encoder is broken.
The hardware detection uses a comparator or an operational amplifier to convert the A, B, C differential signal into a single-ended signal, and when the encoder is abnormal, the A, B, C differential signal output by the encoder may have a bias or phase deviation condition. As shown in fig. 1, the normal differential signal is shown on the left side, and the bias differential signal V1 is shown on the upper right side, a bias voltage may occur in a certain phase from the encoder, that is, a certain level is low, at which time the encoder may still be able to operate due to aging or interference; while the value of A + -minus A-represents when 1 and when 0, different criteria (typically 200mV or 4.5V) exist; if the situation happens, the comparator or the operational amplifier cannot complete the disconnection detection or false alarm at the moment. Or for the normal differential signal on the left side, the lower part on the right side shows a phase deviation differential signal V2, a certain phase sent by the encoder may have a phase deviation, that is, a certain path of high level is delayed, the motor position is abnormal, and the motor is shaken or idled, so that the detection cannot be well completed at this time, and the false alarm phenomenon occurs.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model is to provide an encoder broken string detection circuitry for overcome among the prior art encoder can't carry out the broken string when static and standby and detect out A, B, C looks arbitrary some looks broken string, difference signal appear bias voltage easily or the defect that leads to the false retrieval partially mutually.
The utility model discloses an above-mentioned technical problem is solved through following technical scheme:
a kind of encoder broken string detection circuit, including voltage conversion circuit, comparator circuit and decision circuit;
the voltage conversion circuit comprises N voltage conversion sub-circuits, and each voltage conversion sub-circuit is respectively connected with a phase difference division signal output by the encoder and used for converting the differential signal into a single-ended signal and outputting the single-ended signal;
the comparison circuit comprises N first comparison sub-circuits, each first comparison sub-circuit is connected with one voltage conversion sub-circuit and used for comparing the voltage of the single-ended signal output by the connected voltage conversion sub-circuit with the reference voltage for detecting disconnection and outputting a comparison result;
the judgment circuit is respectively connected with the N first comparison sub-circuits and is used for carrying out logic judgment according to comparison results output by the N first comparison sub-circuits and outputting detection results;
wherein N is 1, 2 or 3.
Preferably, the voltage conversion sub-circuit comprises a first resistor, a second resistor, a third resistor and a first capacitor;
one end of the first resistor is used as a positive input end of the voltage conversion sub-circuit and is used for connecting a positive voltage output end of the connected differential signal, and one end of the second resistor is used as a negative input end of the voltage conversion sub-circuit and is used for connecting a negative voltage output end of the connected differential signal;
the other end of the first resistor is connected with the other end of the second resistor, one end of the third resistor and one end of the first capacitor are connected and used as output ends of the voltage conversion sub-circuit for outputting single-ended signals, and the other end of the third resistor and the other end of the first capacitor are grounded.
Preferably, the voltage converting sub-circuit is further configured to bias and offset the connected differential signal to generate a standard differential signal having a high level symmetrical to a low level and a positive voltage aligned with a negative voltage.
Preferably, the voltage conversion sub-circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor;
one end of the fourth resistor is used as the positive input end of the voltage conversion sub-circuit and is used for connecting the positive voltage output ends of the connected differential signals, and one end of the fifth resistor is used as the negative input end of the voltage conversion sub-circuit and is used for connecting the negative voltage output ends of the connected differential signals;
the other end of the fourth resistor is connected with one end of the sixth resistor, one end of the second capacitor and one end of the fourth capacitor, the other end of the second capacitor is grounded, the other end of the fifth resistor is connected with one end of the seventh resistor, one end of the third capacitor and the other end of the fourth capacitor, the other end of the third capacitor is grounded, the other end of the sixth resistor and the other end of the seventh resistor are electrically connected with one end of the eighth resistor and one end of the fifth capacitor to serve as the output end of the voltage conversion sub-circuit and used for outputting a single-ended signal, and the other end of the eighth resistor and the other end of the fifth capacitor are grounded.
Preferably, the first comparison sub-circuit comprises a first comparator; the positive input end of the first comparator is connected with a voltage conversion sub-circuit, the negative input end of the first comparator inputs a disconnection detection reference voltage, and the output end of the first comparator outputs a comparison result;
the judging circuit comprises a microprocessor, and the input end of the microprocessor is connected with the output ends of the N first comparison sub-circuits.
Preferably, the disconnection detection reference voltages in the N first comparison sub-circuits are all equal.
Preferably, the judgment circuit comprises a microprocessor, and an analog-to-digital conversion unit of the microprocessor is respectively connected with the N first comparison sub-circuits and used for outputting the reference voltage for detecting the disconnection;
or, the comparison circuit further comprises a reference voltage circuit, and the reference voltage circuit comprises a first resistance voltage division circuit or a first analog-to-digital conversion circuit:
the first resistance voltage division circuit comprises a power supply, a ninth resistor and a tenth resistor; one end of the ninth resistor is connected with the power supply, the other end of the ninth resistor is connected with one end of the tenth resistor, the disconnection detection reference voltage is output to the N first comparison sub-circuits, and the other end of the tenth resistor is grounded;
the first analog-to-digital conversion circuit comprises a first digital-to-analog converter, the input end of the first digital-to-analog converter is connected with the output end of the microprocessor which is included in the judging circuit, and the output end of the first digital-to-analog converter outputs the disconnection detection reference voltage to the N first comparison sub-circuits.
Preferably, the disconnection detection reference voltages in the N first comparison sub-circuits are not all equal.
Preferably, the comparison circuit further includes N reference voltage sub-circuits, and the reference voltage sub-circuit includes a second resistance voltage dividing circuit or a second analog-to-digital conversion circuit:
the second resistance voltage division circuit comprises a power supply, an eleventh resistor and a twelfth resistor; one end of the eleventh resistor is connected with the power supply, the other end of the eleventh resistor is connected with one end of the twelfth resistor, the disconnection detection reference voltage is output to one of the N first comparison sub-circuits, and the other end of the twelfth resistor is grounded;
the second analog-to-digital conversion circuit comprises a second digital-to-analog converter, the input end of the second digital-to-analog converter is connected with the output end of the microprocessor of the judging circuit, and the output end of the second digital-to-analog converter outputs the disconnection detection reference voltage to one of the N first comparison sub-circuits.
Preferably, the comparison circuit further comprises N second comparison sub-circuits;
the second comparator sub-circuit comprises a second comparator, the positive input end of the second comparator is connected with the positive input end of the first comparator, the negative input end of the second comparator is connected with the disconnection detection reference voltage, and the output end of the second comparator is connected with the alarm device or the input end of the microprocessor included in the judgment circuit.
The utility model discloses an actively advance the effect and lie in: the encoder disconnection detection circuit comprises a voltage conversion circuit, a comparison circuit and a judgment circuit, adopts simple resistors, capacitors and comparators to complete detection of encoder disconnection, and is high in reliability; the disconnection detection can be carried out when the encoder is static and in standby; any one of the encoder A, B, C phases can be detected to be broken; the method can detect the bias voltage and the phase deviation of the differential voltage when the encoder has the problems of the bias voltage and the phase deviation of the differential voltage as usual, adapt to the bias voltage degree of the differential voltage by adjusting the resistance value of the resistor and the reference voltage value of the broken line detection, and adapt to the bias phase degree of the differential voltage by adjusting the resistance value of the resistor and the capacitance value of the capacitor.
Drawings
FIG. 1 is a schematic diagram of differential voltage signal biasing and phase deviation.
Fig. 2 is a circuit configuration diagram of an encoder disconnection detection circuit according to embodiment 1 of the present invention.
Fig. 3 is a circuit configuration diagram of an encoder disconnection detection circuit according to embodiment 2 of the present invention.
Fig. 4 is a circuit configuration diagram of the disconnection detection reference voltage according to embodiment 3 of the present invention.
Fig. 5 is a circuit configuration diagram of the disconnection detection reference voltage according to embodiment 4 of the present invention.
Fig. 6 is a circuit configuration diagram of the disconnection detection reference voltage according to embodiment 5 of the present invention.
Fig. 7 is a circuit configuration diagram of the disconnection detection reference voltage according to embodiment 6 of the present invention.
Fig. 8 is a circuit configuration diagram of the disconnection detection reference voltage according to embodiment 7 of the present invention.
Fig. 9 is a circuit configuration diagram of an output access determination circuit of a second comparator according to embodiment 8 of the present invention.
Fig. 10 is a circuit configuration diagram of an output connection alarm device of a second comparator according to embodiment 8 of the present invention.
Detailed Description
The present invention is further illustrated by way of the following examples, which are not intended to limit the scope of the invention.
Example 1
As shown in fig. 2, the present embodiment provides an encoder disconnection detection circuit, which is mainly for an encoder that outputs in a differential manner, and includes a voltage conversion circuit 1, a comparison circuit 2, and a determination circuit 3.
The voltage conversion circuit 1 comprises N voltage conversion sub-circuits, each voltage conversion sub-circuit is respectively connected with a phase difference signal output by the encoder and is used for converting the differential signal into a single-ended signal and outputting the single-ended signal; the comparison circuit 2 comprises N first comparison sub-circuits, each first comparison sub-circuit is respectively connected with one voltage conversion sub-circuit and is used for comparing the voltage of the single-ended signal output by the connected voltage conversion sub-circuit with the reference voltage for detecting disconnection and outputting a comparison result; the judgment circuit 3 is respectively connected with the N first comparison sub-circuits and is used for carrying out logic judgment according to comparison results output by the N first comparison sub-circuits and outputting detection results;
wherein N is 1, 2 or 3.
The encoder disconnection detection circuit can be adapted to an incremental encoder having A, B, C three-phase differential signal outputs for which N is 3, i.e. the encoder disconnection detection circuit adapted to an incremental encoder includes A, B, C three-phase voltage conversion sub-circuits and A, B, C three-phase comparison sub-circuits. The circuit configuration of the present embodiment will be described in detail below by taking an a-phase circuit as an example, which is applied to an encoder disconnection detection circuit of an incremental encoder.
The A-phase voltage converting sub-circuit comprises a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1. The a-phase first comparison sub-circuit includes a first comparator U1.
One end of the first resistor R1 is used as the positive input end of the A phase difference converting sub-circuit and is used for connecting the positive voltage output end of the connected A phase difference signal, and one end of the second resistor R2 is used as the negative input end of the A phase difference converting sub-circuit and is used for connecting the negative voltage output end of the connected A phase difference signal; the other end of the first resistor R1 is connected with the other end of the second resistor R2, and one end of the third resistor R3 and one end of the first capacitor C1 are connected asAn output terminal of the voltage conversion sub-circuit for outputting the single-ended signal VAThe other end of the third resistor R3 and the other end of the first capacitor C1 are grounded.
The first resistor R1, the second resistor R2 and the third resistor R3 form a resistor star-shaped circuit which is connected with differential voltage and converts the differential voltage into single-ended voltage VAThe resistance values of the three resistors can be freely adjusted to finish the proportion adjustment of converting the differential voltage into the single-ended voltage. The first capacitor C1 is connected to the single-end voltage VAAnd the ground, and is used for smoothing and removing signal burrs.
The single-ended signal VAThe positive input end of the first comparator U1 is connected, and the negative input end of the first comparator U1 is connected with an A-phase disconnection detection reference voltage VRefThe two are compared by a comparator when the single-ended signal V isAGreater than A phase disconnection detection reference voltage VRefAnd outputting a high level when the current is high, and otherwise, outputting a low level. The output of the first comparator U1 outputs the result of the comparison.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1 is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase a is disconnected. For example, if the comparator is positive, when the comparison result is high, it is determined that phase a is not disconnected; otherwise, when the comparison result is low level, the A phase is judged to have broken line. For another example, if the comparator is negative, when the comparison result is high, it is determined that phase a is disconnected; otherwise, when the comparison result is low level, the phase A is judged not to be broken.
B. The C-phase circuit is similar in circuit configuration to the a-phase circuit, and for distinction from the a-phase circuit, the components of the B-phase circuit are labeled with a suffix', and the components of the C-phase circuit are labeled with a suffix ". As shown in fig. 2, the B-phase voltage converting sub-circuit includes a first resistor R1 ', a second resistor R2', a third resistor R3 'and a first capacitor C1'. The B-phase first comparison sub-circuit includes a first comparator U1'.
One end of the first resistor R1' is used as the positive input end of the B-phase voltage converting sub-circuit, and is used for connecting the positive voltage output end of the connected B-phase differential signal,one end of a second resistor R2' is used as the negative input end of the B-phase voltage conversion sub-circuit and is used for connecting the negative voltage output end of the connected B-phase differential signal; the other end of the first resistor R1 'is connected with the other end of the second resistor R2', one end of the third resistor R3 'and one end of the first capacitor C1' are connected as the output end of the voltage conversion sub-circuit, and the output end is used for outputting a single-ended signal VBThe other end of the third resistor R3 'and the other end of the first capacitor C1' are grounded.
The first resistor R1 ', the second resistor R2 ' and the third resistor R3 ' form a resistor star circuit which is connected with differential voltage and converts the differential voltage into single-ended voltage VBThe resistance values of the three resistors can be freely adjusted to finish the proportion adjustment of converting the differential voltage into the single-ended voltage. The first capacitor C1' is connected to the single-end voltage VBAnd the ground, and is used for smoothing and removing signal burrs.
The single-ended signal VBThe positive input end of the first comparator U1 'is connected, and the negative input end of the first comparator U1' is connected with a B-phase disconnection detection reference voltage VRef', the two are compared by a comparator when the single-ended signal V isBGreater than B phase disconnection detection reference voltage VRefWhen outputting high level, otherwise, outputting low level. The output of the first comparator U1' outputs the comparison result.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1' is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase B is disconnected.
As shown in fig. 2, the C-phase voltage converting sub-circuit includes a first resistor R1 ", a second resistor R2", a third resistor R3 ", and a first capacitor C1". The C-phase first comparator sub-circuit includes a first comparator U1 ".
One end of the first resistor R1 'is used as the positive input end of the C phase difference converting sub-circuit and is used for connecting the positive voltage output end of the connected C phase difference signal, and one end of the second resistor R2' is used as the negative input end of the C phase difference converting sub-circuit and is used for connecting the negative voltage output end of the connected C phase difference signal; the other end of the first resistor R1' and a second resistorThe other end of the R2 ' is connected with one end of a third resistor R3 ' and one end of a first capacitor C1 ' to serve as an output end of the C-phase voltage conversion sub-circuit, and the output end of the C-phase voltage conversion sub-circuit is used for outputting a single-ended signal VCThe other end of the third resistor R3 'and the other end of the first capacitor C1' are grounded.
The first resistor R1 ', the second resistor R2 ' and the third resistor R3 ' form a resistor star-shaped circuit which is connected with differential voltage and converts the differential voltage into single-ended voltage VCThe resistance values of the three resistors can be freely adjusted to finish the proportion adjustment of converting the differential voltage into the single-ended voltage. The first capacitor C1' is connected to the single-end voltage VCAnd the ground, and is used for smoothing and removing signal burrs.
The single-ended signal VCThe positive input end of a first comparator U1 'is connected, and the negative input end of the first comparator U1' is connected with a C-phase disconnection detection reference voltage VRefComparing the two signals by a comparator when the single end signal V is single end signalCGreater than C phase disconnection detection reference voltage VRefAnd outputting high level when the voltage is high, and outputting low level when the voltage is low. The output of the first comparator U1 "outputs the result of the comparison.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1' is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase C is disconnected.
The encoder disconnection detection circuit may also be adapted to an absolute encoder, which has one or two differential signal outputs, for which N is 1 or 2, i.e. the encoder disconnection detection circuit adapted to an absolute encoder comprises one or two voltage conversion sub-circuits, one or two first comparison sub-circuits. The circuit structure of the encoder disconnection detection circuit applicable to the absolute encoder and the circuit structure of the encoder disconnection detection circuit applicable to the incremental encoder are basically the same except that the number of the voltage conversion sub-circuits and the number of the first comparison sub-circuits are different, and the description is omitted here. When the absolute encoder is subjected to disconnection detection, the voltage conversion sub-circuit and the first comparison sub-circuit which are not used in the encoder disconnection detection circuit suitable for the incremental encoder are not used, or the microprocessor shields the result output by the corresponding comparison circuit, and any one phase or two phases in the shield A, B, C can be selected, so that the absolute encoder can be used for disconnection detection.
Example 2
This embodiment is a further improvement on embodiment 1, in which the voltage compensation sub-circuit is further configured to perform bias and phase offset compensation on the connected differential signals to generate a standard differential signal with a high level symmetrical to a low level and a positive voltage aligned with a negative voltage, and convert the standard differential signal into a single-ended signal and output the single-ended signal.
The encoder disconnection detection circuit can be adapted to an incremental encoder having A, B, C three-phase differential signal outputs for which N is 3, i.e. the encoder disconnection detection circuit adapted to an incremental encoder includes A, B, C three-phase voltage conversion sub-circuits and A, B, C three-phase comparison sub-circuits. The circuit configuration of the present embodiment will be described in detail below by taking an a-phase circuit as an example, which is applied to an encoder disconnection detection circuit of an incremental encoder.
As shown in fig. 3, the a-phase voltage converting sub-circuit includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5. The a-phase first comparison sub-circuit includes a first comparator U1. One end of a fourth resistor R4 is used as the positive input end of the A phase difference signal conversion sub-circuit and is used for connecting the positive voltage output end of the connected A phase difference signal, and one end of a fifth resistor R5 is used as the negative input end of the A phase difference signal conversion sub-circuit and is used for connecting the negative voltage output end of the connected A phase difference signal; the other end of the fourth resistor R4 is connected with one end of a sixth resistor R6, one end of a second capacitor C2 and one end of a fourth capacitor C4, the other end of the second capacitor C2 is grounded, the other end of the fifth resistor R5 is connected with one end of a seventh resistor R7, one end of a third capacitor C3 and the other end of the fourth capacitor C4, the other end of the third capacitor C3 is grounded, the other end of the sixth resistor R6 and the other end of the seventh resistor R7 are electrically connected with one end of an eighth resistor R8 and one end of a fifth capacitor C5 together to serve as an A-phase voltage converterOutput terminal of circuit for outputting single-ended signal VAThe other end of the eighth resistor R8 and the other end of the fifth capacitor C5 are grounded.
The fourth resistor R4 and the second capacitor C2 form a low pass filter circuit to delay the voltage rise time and synchronize the high level time for completing the phase offset compensation of the a phase difference divided signal positive voltage. The specific phase deviation time is determined by the parameters of the fourth resistor R4 and the second capacitor C2, the utility model relates to a parameter, the maximum compensation of the phase deviation time is 500 uS.
The fifth resistor R5 and the third capacitor C3 also form a low pass filter circuit to delay the voltage rise time and synchronize the high level time for phase offset compensation of the negative voltage of the a phase difference divided signal.
One end of a sixth resistor R6 is connected with the other end of the fourth resistor R4, one end of a seventh resistor R7 is connected with the other end of the fifth resistor R5, the other end of the sixth resistor R6 is connected with the other end of the seventh resistor R7, and single-ended voltage V is outputA. The fourth resistor R4, the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 form a series resistor together, and one end of the eighth resistor R8 is connected with the single-ended voltage VAThe other end of the resistor is grounded, and an eighth resistor R8 is used as a parallel resistor; the voltage division function of the series resistor and the parallel resistor and the A-phase disconnection detection reference voltage value input by the negative end of the first comparator U1 together complete the bias compensation of the A-phase differential voltage. The bias ratio (i.e. the ratio of the voltage value of the voltage difference relative to the normal voltage) can be adjusted by adjusting the above parameters, and the parameter ratio range can be as follows: 0.01 x 2 (1-0.01 x 2), wherein 0.01 is a resistance error value.
The fourth capacitor C4 is connected across the positive and negative voltages of the a-phase differential signal to form a differential mode filter for filtering noise of the differential signal. The fifth capacitor C5 is connected to the single-ended voltage VAAnd the ground, and is used for smoothing and removing signal burrs.
The processed single-ended signal VAThe positive input end of the first comparator U1 is connected, and the negative input end of the first comparator U1 is connected with an A-phase disconnection detection reference voltage VRefThe two are compared by a comparator when the single-ended signal V isAGreater than phase AReference voltage V for wire break detectionRefAnd outputting a high level when the current is high, and otherwise, outputting a low level. The output of the first comparator U1 outputs the result of the comparison.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1 is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase a is disconnected. For example, if the comparator is positive, when the comparison result is high, it is determined that phase a is not disconnected; otherwise, when the comparison result is low level, the A phase is judged to have broken line. For another example, if the comparator is negative, when the comparison result is high, it is determined that phase a is disconnected; otherwise, when the comparison result is low level, the phase A is judged not to be broken.
B. The C-phase circuit is similar in circuit configuration to the a-phase circuit, and for distinction from the a-phase circuit, the components of the B-phase circuit are labeled with a suffix', and the components of the C-phase circuit are labeled with a suffix ". As shown in fig. 3, the B-phase voltage converting sub-circuit includes a fourth resistor R4 ', a fifth resistor R5', a sixth resistor R6 ', a seventh resistor R7', an eighth resistor R8 ', a second capacitor C2', a third capacitor C3 ', a fourth capacitor C4', and a fifth capacitor C5 ', and the B-phase first comparing sub-circuit includes a first comparator U1'.
One end of a fourth resistor R4 'is used as the positive input end of the B phase difference signal conversion sub-circuit and is used for connecting the positive voltage output end of the connected B phase difference signal, and one end of a fifth resistor R5' is used as the negative input end of the B phase voltage conversion sub-circuit and is used for connecting the negative voltage output end of the connected B phase difference signal; the other end of the fourth resistor R4 'is connected to one end of the sixth resistor R6', one end of the second capacitor C2 'and one end of the fourth capacitor C4', the other end of the second capacitor C2 'is grounded, the other end of the fifth resistor R5' is connected to one end of the seventh resistor R7 ', one end of the third capacitor C3' and the other end of the fourth capacitor C4 ', the other end of the third capacitor C3' is grounded, the other end of the sixth resistor R6 'and the other end of the seventh resistor R7' are electrically connected to one end of the fifth resistor R5 'and one end of the fifth capacitor C5', and serve as output ends of the B-phase voltage converter circuits for outputting the single-ended signal V6BThe other end of the eighth resistor R8 'and the other end of the fifth capacitor C5' are grounded.
The fourth resistor R4 'and the second capacitor C2' form a low pass filter circuit for performing phase offset compensation of the positive voltage of the phase difference signal B. The fifth resistor R5 'and the third capacitor C3' also form a low pass filter circuit for performing phase offset compensation of the negative voltage of the phase difference divided signal B.
The fourth resistor R4 ', the fifth resistor R5 ', the sixth resistor R6 ' and the seventh resistor R7 ' jointly form a series resistor, and one end of the eighth resistor R8 ' is connected with the single-ended voltage VBThe other end of the resistor is grounded, and an eighth resistor R8' forms a parallel resistor; the voltage division function of the series resistor and the parallel resistor and the B-phase disconnection detection reference voltage value input by the negative end of the first comparator U1' jointly complete bias compensation of the B-phase difference divided voltage.
The fourth capacitor C4' is connected across the positive and negative voltages of the phase difference differential signal B to form a differential mode filter for filtering out noise waves of the differential signal. The fifth capacitor C5' is connected to the single-ended voltage VBAnd the ground, and is used for smoothing and removing signal burrs.
The processed single-ended signal VBThe positive input end of the first comparator U1 'is connected, and the negative input end of the first comparator U1' is connected with a B-phase disconnection detection reference voltage VRef', the two are compared by a comparator when the single-ended signal V isBGreater than B phase disconnection detection reference voltage VRefWhen outputting high level, otherwise, outputting low level. The output of the first comparator U1' outputs the comparison result.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1' is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase B is disconnected.
As shown in fig. 3, the C-phase voltage converting sub-circuit includes a fourth resistor R4 ", a fifth resistor R5", a sixth resistor R6 ", a seventh resistor R7", an eighth resistor R8 ", a second capacitor C2", a third capacitor C3 ", a fourth capacitor C4", and a fifth capacitor C5 ", and the C-phase first comparing sub-circuit includes a first comparator U1".
One end of a fourth resistor R4 'is used as the positive input end of the C phase difference converting sub-circuit and is used for connecting the positive voltage output end of the connected C phase difference signal, and one end of a fifth resistor R5' is used as the negative input end of the C phase difference converting sub-circuit and is used for connecting the negative voltage output end of the connected C phase difference signal; the other end of the fourth resistor R4 ' is connected with one end of a sixth resistor R6 ', one end of a second capacitor C2 ' and one end of a fourth capacitor C4 ', the other end of the second capacitor C2 ' is grounded, the other end of the fifth resistor R5 ' is connected with one end of a seventh resistor R7 ', one end of a third capacitor C3 ' and the other end of the fourth capacitor C4 ', the other end of the third capacitor C3 ' is grounded, the other end of the sixth resistor R6 ' and the other end of the seventh resistor R7 ' are electrically connected with one end of an eighth resistor R8 ' and one end of the fifth capacitor C5 ' to serve as output ends of the C-phase voltage conversion sub-circuit, and the output ends of the single-end signal V6 ' and the single-end signal V5CThe other end of the eighth resistor R8 'and the other end of the fifth capacitor C5' are grounded.
The fourth resistor R4 'and the second capacitor C2' form a low pass filter circuit for performing phase offset compensation of the positive voltage of the phase difference signal C. The fifth resistor R5 'and the third capacitor C3' also form a low pass filter circuit for performing phase offset compensation of the negative voltage of the phase difference C divided signal.
The fourth resistor R4 ', the fifth resistor R5 ', the sixth resistor R6 ' and the seventh resistor R7 ' jointly form a series resistor, and one end of the eighth resistor R8 ' is connected with the single-end voltage VCThe other end of the resistor is grounded, and an eighth resistor R8' forms a parallel resistor; the voltage division function of the series resistor and the parallel resistor and the C-phase disconnection detection reference voltage value input by the negative end of the first comparator U1' jointly complete the bias compensation of the C-phase difference divided voltage.
The fourth capacitor C4' is connected across the positive and negative voltages of the C phase difference signal to form a differential mode filter for filtering noise wave of the difference signal. The fifth capacitor C5' is connected to the single-end voltage VCAnd the ground, and is used for smoothing and removing signal burrs.
The processed single-ended signal VCConnected to the positive input of a first comparator U1 ″, a firstThe negative input end of the comparator U1' is connected with a C-phase disconnection detection reference voltage VRefComparing the two signals by a comparator when the single end signal V is single end signalCGreater than C phase disconnection detection reference voltage VRefAnd outputting high level when the voltage is high, and outputting low level when the voltage is low. The output of the first comparator U1 "outputs the result of the comparison.
Further, the judgment circuit 3 comprises a microprocessor, the comparison result output by the output end of the first comparator U1' is connected to the microprocessor, and the microprocessor performs logic judgment on the comparison result to judge whether the phase C is disconnected.
The encoder disconnection detection circuit may also be adapted to an absolute encoder, which has one or two differential signal outputs, for which N is 1 or 2, i.e. the encoder disconnection detection circuit adapted to an absolute encoder comprises one or two voltage conversion sub-circuits, one or two first comparison sub-circuits. The circuit structure of the encoder disconnection detection circuit applicable to the absolute encoder and the circuit structure of the encoder disconnection detection circuit applicable to the incremental encoder are basically the same except that the number of the voltage conversion sub-circuits and the number of the first comparison sub-circuits are different, and the description is omitted here. When the absolute encoder is subjected to disconnection detection, the voltage conversion sub-circuit and the first comparison sub-circuit which are not used in the encoder disconnection detection circuit suitable for the incremental encoder are not used, or the microprocessor shields the result output by the corresponding comparison circuit, and any one phase or two phases in the shield A, B, C can be selected, so that the absolute encoder can be used for disconnection detection.
Example 3
This embodiment is a further improvement on embodiment 1 or 2, and specifically shows a first setting manner of the disconnection detection reference voltage of the first comparators U1, U1', U1 ″ of the comparison circuit 2 in this embodiment. As shown in fig. 4, the disconnection detection reference voltages of the first comparators U1, U1', U1 "of the present embodiment are equal and are uniformly supplied from the analog-to-digital conversion units (DACs) of the microprocessor in the determination circuit 3. An analog-to-digital conversion unit (DAC) of the microprocessor is respectively connected with the first comparators of the three first comparison sub-circuitsThe negative input ends of U1, U1 'and U1' are connected for outputting a reference voltage V for detecting disconnectionRef。
Example 4
This embodiment is a further improvement on embodiment 1 or 2, and specifically shows a second setting manner of the disconnection detection reference voltage of the first comparators U1, U1', U1 ″ of the comparison circuit 2 in this embodiment. As shown in fig. 5, the reference voltages for detecting the disconnection of the first comparators U1, U1' and U1 "are equal and are provided by the resistor voltage divider circuit. The resistance voltage-dividing circuit comprises a power supply VCCA ninth resistor R9 and a tenth resistor R10, wherein one end of the ninth resistor R9 is connected with a power supply VCCThe other end of the resistor is connected with one end of a tenth resistor R10 to output a reference voltage V for detecting disconnectionRefThe other end of the tenth resistor R10 is grounded, and the output disconnection detection reference voltage VRefTo the negative inputs of the first comparators U1, U1', U1 "of the three first comparison sub-circuits.
Example 5
This embodiment is a further improvement on embodiment 1 or 2, and specifically shows a third setting manner of the disconnection detection reference voltage of the first comparators U1, U1', U1 ″ of the comparison circuit 2 in this embodiment. As shown in fig. 6, the disconnection detection reference voltages of the first comparators U1, U1' and U1 "of the present embodiment are equal and are provided uniformly by an independent analog-to-digital conversion unit (DAC) -the first analog-to-digital converter D1. The input end of the first analog-to-digital converter D1 is connected with the output end of the microprocessor of the decision circuit 3, the output end of the first analog-to-digital converter D1 is connected with the negative input ends of the first comparators U1, U1 'and U1' of the three first comparison sub-circuits, and the output ends are used for outputting the reference voltage V for detecting the disconnectionRef。
Example 6
This embodiment is a further improvement on embodiment 1 or 2, and specifically shows a fourth setting manner of the disconnection detection reference voltage of the first comparators U1, U1', U1 ″ of the comparison circuit 2 in this embodiment. As shown in FIG. 7, the reference voltage V for detecting the disconnection of the first comparators U1, U1', U1 ″ of the present embodimentRef、VRef′、VRefIncompleteEqual, are provided by three resistance bleeder circuits respectively.
The A-phase resistance voltage-dividing circuit comprises a power supply VCCAn eleventh resistor R11 and a twelfth resistor R12, wherein one end of the eleventh resistor R11 is connected with a power supply VCCThe other end of the resistor is connected with one end of a twelfth resistor R12 to output an A-phase disconnection detection reference voltage VRefAnd the other end of the twelfth resistor R12 is grounded.
The B-phase resistance voltage-dividing circuit comprises a power supply VCCAn eleventh resistor R11 ' and a twelfth resistor R12 ', one end of the eleventh resistor R11 ' being connected to the power supply VCCThe other end of the fourth resistor is connected with one end of a twelfth resistor R12' and outputs a reference voltage V for detecting the disconnection of the phase BRef', the other end of the twelfth resistor R12' is grounded.
The C-phase resistance voltage-dividing circuit comprises a power supply VCCOne end of an eleventh resistor R11 ' and a twelfth resistor R12 ', an eleventh resistor R11 ' is connected with a power supply VCCThe other end of the resistor is connected with one end of a twelfth resistor R12' and outputs a reference voltage V for detecting the disconnection of the phase BRefThe other end of the twelfth resistor R12' is connected to ground.
Example 7
This embodiment is a further improvement on embodiment 1 or 2, and specifically shows a fifth arrangement of the disconnection detection reference voltage of the first comparators U1, U1', U1 ″ of the comparison circuit 2 in this embodiment. As shown in FIG. 8, the reference voltage V for detecting the disconnection of the first comparators U1, U1', U1 ″ of the present embodimentRef、VRef′、VRef"not exactly equal, provided by the three analog-to-digital conversion units (DACs) -the second analog-to-digital converters D2, D2', D2", respectively. The input ends of the second analog-to-digital converters D2, D2 'and D2' are connected with the output end of the microprocessor of the judging circuit 3, the output ends of the second analog-to-digital converters D2, D2 'and D2' are connected with the negative input ends of the first comparators U1, U1 'and U1' of the three first comparison sub-circuits, and are used for outputting the reference voltage V for detecting disconnectionRef、VRef′、VRef″。
Example 8
The A, B, C three-phase detection results of embodiments 1-7 are directly sent to the judgment circuit 3 for logic judgment, and the three-phase detection results can be processed into wired-phase detection results, so that fault alarm can be performed conveniently.
As shown in fig. 9 and 10, the comparison circuit 2 of the present embodiment further includes three second comparison sub-circuits, which are respectively connected to the positive input terminals of the three first comparison sub-circuits. The A-phase second comparator sub-circuit comprises a second comparator U2, the positive input end of which is connected with the positive input end of the first comparator U1, and the negative input end of which is connected with an A-phase disconnection detection reference voltage VRef(ii) a The B-phase second comparator sub-circuit comprises a second comparator U2 'with a positive input terminal connected with the positive input terminal of the first comparator U1' and a negative input terminal connected with a B-phase disconnection detection reference voltage VRef'; the C-phase second comparator sub-circuit comprises a second comparator U2 'with a positive input terminal connected with the positive input terminal of the first comparator U1' and a negative input terminal connected with the C-phase disconnection detection reference voltage VRef". The output ends of the second comparators U2, U2 'and U2' are connected, and are connected to the judgment circuit 3 for logic judgment or are directly connected with a sounding or luminous alarm device for fault alarm.
Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that this is by way of example only and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (10)
1. A kind of encoder broken string detection circuit, characterized by, including voltage switching circuit, comparator circuit and decision circuit;
the voltage conversion circuit comprises N voltage conversion sub-circuits, and each voltage conversion sub-circuit is respectively connected with a phase difference signal output by the encoder and used for converting the differential signal into a single-ended signal and outputting the single-ended signal;
the comparison circuit comprises N first comparison sub-circuits, and each first comparison sub-circuit is connected with one voltage conversion sub-circuit and used for comparing the single-ended signal output by the connected voltage conversion sub-circuit with a line break detection reference voltage and outputting a comparison result;
the judgment circuit is respectively connected with the N first comparison sub-circuits and is used for carrying out logic judgment according to comparison results output by the N first comparison sub-circuits and outputting detection results;
wherein N is 1, 2 or 3.
2. The encoder disconnection detection circuit of claim 1, wherein the voltage conversion sub-circuit comprises a first resistor, a second resistor, a third resistor, and a first capacitor;
one end of the first resistor is used as a positive input end of the voltage conversion sub-circuit and is used for connecting a positive voltage output end of the connected differential signal, and one end of the second resistor is used as a negative input end of the voltage conversion sub-circuit and is used for connecting a negative voltage output end of the connected differential signal;
the other end of the first resistor is connected with the other end of the second resistor, one end of the third resistor and one end of the first capacitor are connected and used as output ends of the voltage conversion sub-circuit to output the single-ended signal, and the other end of the third resistor and the other end of the first capacitor are grounded.
3. The encoder outage detection circuit of claim 1, wherein the voltage translation sub-circuit is further configured to bias and offset compensate connected differential signals to produce a standard differential signal with high levels symmetrical to low levels and positive voltages aligned with negative voltages.
4. The encoder disconnection detection circuit of claim 3, wherein the voltage conversion sub-circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a second capacitor, a third capacitor, a fourth capacitor, and a fifth capacitor;
one end of the fourth resistor is used as a positive input end of the voltage conversion sub-circuit and is used for connecting a positive voltage output end of the connected differential signal, and one end of the fifth resistor is used as a negative input end of the voltage conversion sub-circuit and is used for connecting a negative voltage output end of the connected differential signal;
the other end of the fourth resistor is connected with one end of the sixth resistor, one end of the second capacitor and one end of the fourth capacitor, the other end of the second capacitor is grounded, the other end of the fifth resistor is connected with one end of the seventh resistor, one end of the third capacitor and the other end of the fourth capacitor, the other end of the third capacitor is grounded, the other end of the sixth resistor, the other end of the seventh resistor, one end of the eighth resistor and one end of the fifth capacitor are electrically connected together to serve as an output end of the voltage conversion sub-circuit and used for outputting the single-ended signal, and the other end of the eighth resistor and the other end of the fifth capacitor are grounded.
5. The encoder outage detection circuit of claim 1, wherein the first comparison sub-circuit comprises a first comparator; the positive input end of the first comparator is connected with one of the voltage conversion sub-circuits, the negative input end of the first comparator inputs the disconnection detection reference voltage, and the output end of the first comparator outputs the comparison result;
the judging circuit comprises a microprocessor, and the input end of the microprocessor is connected with the output ends of the N first comparison sub-circuits.
6. The encoder disconnection detection circuit of any of claims 1-4, wherein the disconnection detection reference voltages in the N first comparison sub-circuits are all equal.
7. The circuit for detecting the disconnection of the encoder according to claim 6, wherein the determining circuit comprises a microprocessor, and analog-to-digital conversion units of the microprocessor are respectively connected with the N first comparing sub-circuits and used for outputting the reference voltage for detecting the disconnection;
or, the comparison circuit further includes a reference voltage circuit, and the reference voltage circuit includes a first resistance voltage-dividing circuit or a first analog-to-digital conversion circuit:
the first resistance voltage division circuit comprises a power supply, a ninth resistor and a tenth resistor; one end of the ninth resistor is connected with the power supply, the other end of the ninth resistor is connected with one end of the tenth resistor, the disconnection detection reference voltage is output to the N first comparator circuits, and the other end of the tenth resistor is grounded;
the first analog-to-digital conversion circuit comprises a first digital-to-analog converter, the input end of the first digital-to-analog converter is connected with the output end of the microprocessor which is included in the judging circuit, and the output end of the first digital-to-analog converter outputs the disconnection detection reference voltage to the N first comparison sub-circuits.
8. The encoder disconnection detection circuit of any of claims 1-4, wherein the disconnection detection reference voltages in the N first comparison sub-circuits are not all equal.
9. The encoder disconnection detection circuit of claim 8, wherein the comparison circuit further comprises N reference voltage sub-circuits, the reference voltage sub-circuits comprising a second resistive voltage divider circuit or a second analog-to-digital conversion circuit:
the second resistance voltage division circuit comprises a power supply, an eleventh resistor and a twelfth resistor; one end of the eleventh resistor is connected with the power supply, the other end of the eleventh resistor is connected with one end of the twelfth resistor, the disconnection detection reference voltage is output to one of the N first comparator circuits, and the other end of the twelfth resistor is grounded;
the second analog-to-digital conversion circuit comprises a second digital-to-analog converter, the input end of the second digital-to-analog converter is connected with the output end of the microprocessor of the judging circuit, and the output end of the second digital-to-analog converter outputs the disconnection detection reference voltage to one of the N first comparison sub-circuits.
10. The encoder outage detection circuit of claim 5, wherein the comparison circuit further comprises N second comparison sub-circuits;
the second comparator sub-circuit comprises a second comparator, a positive input end of the second comparator is connected with a positive input end of the first comparator, a negative input end of the second comparator is connected with the disconnection detection reference voltage, and an output end of the second comparator is connected with an alarm device or an input end of a microprocessor included in the judgment circuit.
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| CN201920258608.2U CN209928002U (en) | 2019-02-28 | 2019-02-28 | Encoder broken line detection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111189482A (en) * | 2020-01-13 | 2020-05-22 | 珠海格力电器股份有限公司 | Broken line detection device, encoder and broken line detection method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111189482A (en) * | 2020-01-13 | 2020-05-22 | 珠海格力电器股份有限公司 | Broken line detection device, encoder and broken line detection method thereof |
| CN111189482B (en) * | 2020-01-13 | 2021-07-20 | 珠海格力电器股份有限公司 | Broken line detection device, encoder and broken line detection method thereof |
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Address after: Room 5124, building C, 555 Dongchuan Road, Minhang District, Shanghai 200241 Patentee after: SHANGHAI LYNUC NUMERICAL CONTROL TECHNOLOGY CO.,LTD. Address before: 279 Pingfu Road, Xuhui District, Shanghai, 200231 Patentee before: SHANGHAI LYNUC CNC TECHNOLOGY Co.,Ltd. |