JP2004015153A - Counter and counter system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a counter capable of acquiring an accurate value of the number of pulse trains externally received in a short time and to provide a counter system. <P>SOLUTION: The counter 1 for receiving pulse trains from the outside of the counter to count the number of pulse trains wherein a controller 2 for using the count for its control reads the count, is configured to include: a means 8 for latching the count indicating the number of pulse trains when the counter 1 receives a trigger signal from the outside of the counter 1 during the count processing of the pulse trains; a means 11 for issuing interrupt to the controller 2 when receiving the trigger signal; and a means 12 for clearing the latched pulse count when reading of the latched pulse count is completed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a counting device and a counting system used for measurement control and the like, in particular, a counting device and a counting device for counting the number of pulses of a pulse signal in combination with a photoelectric encoder device and the like used for length measurement, angle measurement, and surveying. The present invention relates to a counting system that performs a predetermined control using the count value counted by the counter.
[0002]
[Prior art]
Devices used for length measurement, angle measurement, and surveying include encoders. Briefly describing an encoder, it can be called a kind of converter that encodes various information. One type of encoder is a rotary encoder. A rotary encoder is a kind of rotation angle sensor that converts a rotation angle displacement of a rotation shaft into a digital amount. The sensor measures the length, angle, amount, etc.
In recent years, rotary encoders are exclusively photoelectric. The photoelectric encoder is configured such that a plurality of radial slits are annularly arranged on a rotating disk fixed to a rotating shaft, and a fixed slit is provided on a part of the fixed disk provided in parallel with the rotating disk. The light-emitting element and the light-receiving element are arranged so as to sandwich both the fixed disk and the fixed disk, and the amount of rotation of the rotating shaft is detected by using light passing through both slits of the rotating disk and the fixed disk as a signal.
[0003]
Since the photoelectric signal output in this manner is a pulse signal, that is, a digital signal, it is possible to obtain a physical quantity to be measured by counting this signal with an appropriate digital counter and performing an operation on the number of pulses. .
Specifically, "number of pulses" x "movement amount per pulse" = total movement amount "" number of pulses "x" weight per pulse "= total weight ・" number of pulses "x" angle per pulse " “Amount” = total displacement angle / “number of pulses” × “length per pulse” = length of measured object.
[0004]
Next, a conventional pulse train measurement control system (counting system) will be described with reference to FIGS.
FIG. 6 is a diagram showing the appearance of the pulse train measurement control system, and FIG. 7 is an operation timing chart of the count circuit of the pulse counting unit (counting device).
In FIG. 6, reference numeral 1001 denotes a pulse counting unit for realizing a function of counting a pulse train input from the outside. As shown in FIG. 7, the pulse counting unit counts at the rising edge of the pulse train, and increments the pulse count value (+1 processing).
Reference numeral 1002 denotes a controller that controls the system using the counted number of pulse trains, and reference numeral 1003 denotes a power supply unit that supplies power for operating the controller 1002 and the pulse counting unit 1001.
[0005]
FIG. 8 is a flowchart of a pulse train counting (pulse count) start processing procedure of the pulse counting unit 1001 executed by the controller 1002.
First, before starting the count processing, a pulse count set value is set in step 1021.
Next, in step 1022, a pulse count start command is issued.
At this time, if the pulse from the outside is simply counted, step 1021 is unnecessary.
[0006]
Incidentally, one of the functions of the pulse counting unit 1001 is to simply count an external pulse train input and store the counted value inside the unit. By reading the stored count value at an arbitrary timing, the controller 1002 can know the number of pulses input from the outside.
[0007]
However, the controller 1002 only needs to read the pulse train count value, but does not have to perform the processing content, and needs to perform other control processing. Therefore, normally, the target pulse input number is set to the pulse counting unit 1001, and at the timing when the pulse input number reaches the set value, an interrupt signal is issued from the pulse counting unit 1001 to the controller 1002, and the pulse input number is set. Is notified that the set value has been reached, or by asserting a control signal for handshake (active state, that is, a state of operating as a signal).
[0008]
FIG. 9 is an example of a system control user program stored in the controller 1002.
1031 is an instruction for permitting an interrupt, 1032 is a main program, 1033 is an instruction for ending the main program, 1034 is an interrupt pointer for starting an interrupt program, 1035 is an interrupt program main body, and 1036 is an end for the interrupt program. It is an instruction to do.
[0009]
In the main program 1032, a program of control contents to be performed as the controller 1002 is described. The interrupt program 1035 describes a program having contents specialized for an external interrupt. In the case of this conventional example, a program in response to an interrupt from the pulse counting unit 1001 is described.
[0010]
FIG. 10 shows a processing flow of the interrupt processing of the controller 1002.
Normally, the controller 1002 executes a program by repeating the input processing from the outside → the execution of the program → the output processing to the outside as one cycle. This one cycle time is called a scan time. Therefore, a signal shorter than the scan time cannot be input. Therefore, a pulse counting unit 1001 is required to input and count a signal shorter than the scan time, that is, a pulse.
Also, if the interrupt processing is used, the processing can be performed at the time when the interrupt occurs without depending on the scan time. When an interrupt occurs, the execution of the main program 1032 is temporarily interrupted on the spot, and the interrupt program 1035 according to the interrupt factor is executed. When the interrupt program 1035 ends, the process returns to the next instruction at the time of occurrence of the interrupt, and resumes the interrupted processing of the main program 1032.
[0011]
FIG. 11 shows a processing flow of the pulse counting unit 1001.
Reference numeral 1050 denotes a pulse generation source, which specifically corresponds to the photoelectric encoder described above.
The pulse counting unit 1001 reads out the pulse count set value in step 1051, and counts an external pulse input in step 1052. Next, in step 1053, it is compared whether the pulse count set value matches the counted pulse count value. If they do not match, the process returns to step 1052 again to perform the pulse counting process. If it is determined in step 1053 that the pulse count set value matches the counted pulse count value, an interrupt is issued to the controller 1002 in step 1054.
[0012]
The pulse train input to the pulse counting unit 1001 from the outside as described above is processed according to the procedure shown in FIG. 11, and when the count value reaches the pulse count set value set by the user, an interrupt is issued to the controller 1002. The controller 1002 normally executes the main program 1032, but executes the interrupt program 1035 when receiving an interrupt from the pulse counting unit 1001.
[0013]
[Problems to be solved by the invention]
In the case of the conventional example, since the number of pulse trains has reached the preset pulse count set value, an interrupt is input to the controller 1002 and the corresponding interrupt program 1035 is executed. This function cannot be used unless the user knows in advance the number of pulses at which to issue an interrupt. In addition, even if an interrupt is generated, the pulse count operation is not stopped, and the external pulse signal is not stopped, so that the interrupt generation timing and the count value are not uniquely determined.
[0014]
Note that, even if an interrupt is generated and the pulse count value is obtained in the interrupt program 1035, the problem is not solved.
Hereinafter, the reason will be described with reference to FIG.
FIG. 12 shows the relationship between the counting process of the conventional pulse counting unit 1001 and the interrupt process of the controller 1002.
[0015]
As shown in FIG. 9, unless an interrupt permission instruction 1031 is executed during the execution of the main program 1032, an external interrupt cannot be recognized. If interrupts are not allowed, that is, if interrupts are disabled, external interrupts will not be accepted and, of course, the interrupt program 1035 cannot be executed. Therefore, even if the pulse count value is obtained in the interrupt program 1035, the pulse count value cannot be obtained after all. Even if the interrupt is permitted, as shown in FIG. 12, if the timing of permitting the interrupt is shifted, the pulse count value that can be actually input and the pulse count value that is desired to be input depend on the pulse count value and the execution timing of the interrupt enable command. Values shift.
[0016]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a counting device and a counting system capable of obtaining an accurate value of the number of pulse trains input from the outside in the shortest time.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the counting device according to the present invention inputs a pulse train from the outside of the device, counts the pulse train, and reads the counted value by a controller that performs control using the counted value. A counting device that latches a count value of the number of pulse trains when a trigger signal is applied from outside the device during the counting process of the pulse train, and issues an interrupt to the controller when the trigger signal is applied And means for clearing the latched pulse count value when the latched pulse count value has been read out.
[0018]
Further, in the counting device according to the present invention, when the reading of the latched pulse count value is completed, a predetermined preset value is given to a count current value storage register that performs the pulse train counting process.
[0019]
Further, a counting system according to the present invention includes a counting device that inputs a pulse train from the outside of the device and counts the pulse train, and a controller that reads a count value counted by the counting device and performs control using the read count value. In the counting system, the counting device latches a count value of the number of pulse trains when a trigger signal is applied from outside the device during the counting process of the pulse train, and the trigger signal is applied. Means for issuing an interrupt to the controller when the counter has been read, and means for clearing the latched pulse count when the read of the latched pulse count has been completed. Means for executing an interrupt program when receiving the count value and reading the count value latched by the counting device. It is intended.
[0020]
Further, in the counting system according to the present invention, when the reading of the latched pulse count value is completed, a predetermined preset value is given to a count current value storage register for performing the pulse train counting process.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, a first embodiment of a pulse counting unit (counting device) and a pulse train measurement control system (counting system) according to the present invention will be described with reference to FIGS.
FIG. 1 shows a circuit block of a pulse train measurement control system according to the present invention.
In FIG. 1, 1 is a pulse counting unit, 2 is a controller, 3 is an MPU in the controller 2, 4 is a program storage unit for storing a program executed by the MPU 3 by the controller 2, and 5 is an output from the pulse counting unit 1. This is an interrupt detection unit for detecting an interrupt that has occurred.
[0022]
Reference numeral 6 denotes a pulse train counting unit that counts a pulse train input from the outside, 7 denotes a count present value storage register that stores the count present value of the number of pulses counted by the pulse train counting unit 6, and 8 denotes a latch that latches the count present value. The count current value latch unit 9 is a bus switch that connects the count current value storage register 7 and the count current value latch unit 8. Reference numeral 10 denotes a trigger detecting unit for detecting a trigger from outside the unit during counting of the pulse train, and 11 denotes an interrupt generating unit for receiving an external trigger from the trigger detecting unit 10 and issuing an interrupt to the controller 2.
[0023]
Reference numeral 12 denotes a preset request detection unit for detecting a preset request from outside the unit and transmitting it to the current count latch unit 8, and 13 sets a preset value in the current count value storage register 7 in response to a command from the preset request detection unit 12. In the preset value storage unit, preset values are stored in advance so that a preset operation can be performed at a timing when a preset request is received from outside the unit. A read request detection unit 14 detects a read request from outside the unit.
[0024]
The trigger detection unit 10 outputs a signal to the bus switch 9 and the interrupt generation unit 11 at the same time as receiving a trigger signal from outside the unit.
The bus switch 9 receives the output and switches the connection between the terminals A and C of the internal circuit to the connection between the terminals B and C. That is, the connection of the bus switch is changed from the connection from the terminal A to the terminal C to the terminal B to the terminal C for one pulse time when a trigger is input from the outside.
Therefore, the current value of the pulse count value stored in the count value current value storage register 7 enters the count current value latch unit 8 only once, and as a result, the current value of the pulse count value is latched. While the count current value latch unit 8 is latching, even if a new trigger is received while the latch data is valid, the trigger detection unit 10 interlocks so as not to recognize the trigger. Outputs a signal to the trigger detection unit 10 to notify that "the latch operation is currently in progress". (Terminal A is not connected anywhere. To connect terminal B to terminal C for one pulse time when an external trigger is applied, there is a terminal A to keep the terminal A to terminal C in a steady state. )
[0025]
The interrupt generation unit 11 receives the signal output from the trigger detection unit 10 and issues an interrupt to the controller 2.
As described in the conventional example, the controller 2 executes the interrupt program 1035 starting from the interrupt pointer Ixxx1034 at the timing when the interrupt is received from the pulse counting unit 1 because the program in FIG. .
[0026]
FIG. 2 is a flowchart showing a specific processing procedure of the pulse counting unit 1.
During the input of the pulse train from the outside of the unit, the trigger detection unit 10 checks the presence or absence of an external trigger in step 20. If there is no external trigger, the terminal A-terminal C of the bus switch 9 is connected to the terminal B-terminal. Since it is not necessary to change the connection to C, the pulse count is continued by the pulse train counting unit 6 in step 23, and the current count value is stored in the current count value register 7 in step 24.
[0027]
If it is determined in step 20 that there is an external trigger, it is necessary to change the terminal A-terminal C of the bus switch 9 to the terminal B-terminal C in step 21. In response, the bus switch 9 connects the current count value storage register 7 and the current count value latch unit 8, and issues an interrupt to the controller 2 in step 22. This interrupt has a trigger from the outside, and also serves as a read command that “the pulse count value at the timing when the trigger is entered is latched and can be read”.
[0028]
After receiving the interrupt, the controller 2 temporarily suspends the execution of the main program 1032 and executes the interrupt program 1035. Normally, the pulse count unit 1 is accessed within the interrupt program 1035, and the count value latched by the current count latch 8 is read.
At this time, at the same time as a preset request, it is determined whether to preset the current count value storage register 7 at the timing when the read signal is deasserted or to set a free counter (continue count processing).
[0029]
Next, the processing procedure of the pulse counting unit 1 immediately after the controller 2 reads the latched pulse count value shown in FIG. 3 will be described with reference to FIGS.
[0030]
After it is determined in step 31 that the reading of the latch count has been completed, in step 32, the preset request detector 12 determines ON / OFF of the preset request signal. If it is OFF, it is determined that there is no preset request, and the current count value latch section 8 is cleared in step 34, and the content of the current count value storage register 7 is left as it is. That is, the current count value storage register 7 is used as a free counter without presetting.
If the preset request detector 12 determines in step 32 that the preset request is ON, the preset value specified in the preset value storage 13 is set in the current count value register 7 (step 33). After the preset value is set, the pulse train counting operation starts from that value. Also in this case, the current count value latch section 8 is cleared in step 34.
[0031]
FIG. 4 is an operation timing chart of the count circuit of the pulse counting unit 1 when the preset operation is not performed.
FIG. 5 is an operation timing chart when the preset operation of the count circuit of the pulse counting unit 1 is performed.
The count value continuously updated in the count current value storage register 7 is transferred to the count current value latch unit 8 by applying an external trigger signal. During this time, the count current value storage register 7 continues counting.
[0032]
Since the count value is transferred to the current count latch unit 8 only once at the timing of the application of the external trigger signal, the transferred count value is in the latch state. When the read signal is asserted (active state, that is, a state of operating as a signal), it is read from the current count value latch unit 8. When the read signal becomes deasserted (inactive state), the current count value latch section 8 is cleared to "0". For the purpose of mere latching, it is not necessary to clear “0”. However, depending on the user, the processing may be distinguished depending on the counter value = 0 and ≠ 0. 8 is cleared to "0".
[0033]
The count circuit of the first embodiment latches the count value for reading, and is cleared to "0" after the reading of the count value ends. The count current value storage register 7 is set to a preset value set in advance.
In FIG. 4, since the preset request is not asserted after the reading of the count value is completed, even if the count current value latch unit 8 is cleared to "0", the count current value storage register 7 has counted up to that time. Continue counting from the value.
In FIG. 5, since the preset request is asserted after the reading of the count value is completed, when the count current value latch section 8 is cleared to “0”, the count current value storage register is stored in the preset value storage section 13. 7 is preset and counts continuously from the preset value.
[0034]
As described above, according to the first embodiment, since the count value of the number of pulse trains is latched at the timing when the trigger signal is applied from the outside of the unit, the measurement result can be accurately obtained at the timing when the measurement of the physical quantity to be measured is completed. Can be taken into the unit.
[0035]
In addition, immediately after the count value of the number of pulse trains is latched at the timing when a trigger signal is applied from the outside of the unit, an interrupt is issued to the controller 2 and the interrupted controller 2 can execute the interrupt program 1035. The number of latched pulse trains can be calculated independently. That is, the delay time can be minimized with respect to the control of the number of pulse trains.
[0036]
Also, since the latched pulse count value is automatically cleared at the timing when the reading of the latched pulse train numerical value is completed, unnecessary labor for clearing by the user program can be omitted. No extra processing is required for the user, and the fact that the count current value latch section 8 is cleared to 0 guarantees that the reading has been completed normally, so that the user can calculate the number of pulse trains with ease.
[0037]
Further, by using the preset request, the value of the current count value storage register 7 can be automatically rewritten to an arbitrary value, so that an initial value can be given to the pulse train counting operation.
[0038]
Specific examples include the following two points.
(1) Immediately after a trigger is applied from the outside and the current count value of the number of pulse trains is read out, the count operation always starts from the initial value desired by the user. The value fluctuation range becomes easier to read.
{Circle around (2)} If the current value of the number of pulse trains overflows immediately after the external trigger is input, the counter will operate as a free counter (continue count processing) unless a preset request is issued. The count current value storage register 7 is overwritten with the value desired by the user according to the request, and the pulse train counting operation is started from that value, so that the counting operation can be continued as it is.
[0039]
【The invention's effect】
As described above, according to the present invention, the count value of the number of pulse trains is latched at the timing when the trigger signal is applied from the outside of the unit, so that the measurement result is accurately taken into the unit at the timing of completing the measurement of the physical quantity to be measured. be able to.
Also, immediately after latching the count value of the number of pulse trains at the timing when a trigger signal is applied from the outside of the unit, an interrupt is issued to the controller, and the interrupted controller can execute the interrupt program, regardless of the scan time of the controller. The number of latched pulse trains can be calculated.
In addition, since the latched pulse count value is automatically cleared at the timing when the reading of the latched pulse train numerical value is completed, unnecessary work of clearing the pulse count value by the user program can be omitted.
[0040]
Further, since the value of the count current value storage register can be automatically rewritten to an arbitrary value, an initial value can be given to the pulse train counting operation.
[Brief description of the drawings]
FIG. 1 is a diagram showing circuit blocks of a pulse train measurement control system (counting system) according to Embodiment 1 of the present invention.
FIG. 2 is a flowchart showing a processing procedure of a pulse counting unit (counting device) according to the first embodiment of the present invention.
FIG. 3 is a flowchart illustrating a processing procedure of the pulse counting unit immediately after the controller according to the first embodiment of the present invention reads out the latched pulse count value.
FIG. 4 is an operation timing chart of the count circuit of the pulse counting unit according to the first embodiment of the present invention when a preset operation is not performed.
FIG. 5 is an operation timing chart of the count circuit of the pulse counting unit according to the first embodiment of the present invention when performing a preset operation.
FIG. 6 is an external view of a conventional pulse train measurement control system.
FIG. 7 is an operation timing chart of a count circuit of a pulse counting unit in a conventional example.
FIG. 8 is a flowchart showing a pulse train counting start processing procedure of a pulse counting unit executed by a controller in a conventional example.
FIG. 9 is a diagram showing an example of a user program for system control stored in a controller in a conventional example.
FIG. 10 is a processing flowchart of interrupt processing of a controller in a conventional example.
FIG. 11 is a processing flowchart of a pulse counting unit in a conventional example.
FIG. 12 is a diagram showing a relationship between a counting process of a conventional pulse counting unit and an interrupt process of a controller.
[Explanation of symbols]
1 pulse counting unit, 2 controller, 3 MPU, 4 program storage unit, 5 interrupt detection unit, 6 pulse train counting unit, 7 count current value storage register, 8 count current value latch unit, 9 bus switch, 10 external trigger detection unit, 11 interrupt generator, 12 interrupt generator, 13 preset value storage, 14 read request detector.

Claims (4)

A pulse train is input from the outside of the device, the pulse train is counted, and the counted value is read by a controller that performs control using the counted value. Means for latching the count value of the number of pulse trains when the trigger signal is applied, means for issuing an interrupt to the controller when the trigger signal is applied, and reading of the latched pulse count value is completed. Means for clearing the latched pulse count value. 2. The counting device according to claim 1, wherein when the reading of the latched pulse count value is completed, a predetermined preset value is given to a count current value storage register that performs the pulse train counting process. In a counting system comprising a counting device that inputs a pulse train from the outside of the device and counts the pulse train, and a controller that reads a count value counted by the counting device and performs control using the read count value, The counting device latches a count value of the number of pulse trains when a trigger signal is applied from outside the device during the counting process of the pulse train, and interrupts the controller when the trigger signal is applied. Means for issuing, and means for clearing the latched pulse count value when the latched pulse count value has been read, and wherein the controller executes an interrupt program when interrupted by the counting device. A counting system for reading the count value latched by the counting device. 4. The counting system according to claim 3, wherein when the reading of the latched pulse count value is completed, a predetermined preset value is given to a count current value storage register that performs a counting process of the pulse train. 5.

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