JPS6148082B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a digital display measuring instrument, and in particular has a circuit for switching the displayed value to inches or millimeters when a length measurement pulse signal is supplied to a display device such as a length measuring instrument. This invention relates to digital display measuring instruments. [Prior Art] Electronic length measuring devices can be obtained by using electronic circuits and electronic detection means, and are applied to calipers, micrometers, three-dimensional length measuring devices, and the like. In these electronic length measuring devices, an optical conversion scale having a slit corresponding to a length measurement scale is moved relative to the object to be measured, and the electrical signal from the conversion scale is converted into pulses and counted. At the same time, this count value is counted and displayed. In this manner, the displayed value in the electronic length measuring device is shown as a digital value, and the value is determined by the slit scale formed on the conversion scale. Therefore, when the slit scale of the conversion scale is either inch specification or millimeter specification, it is not possible to know the unit scale of the other. [Problem to be solved by the invention] This problem occurs when a part whose drawing dimensions are expressed in millimeters and another part whose drawing dimensions are expressed in inches are alternately measured with the same digital measuring instrument. It was inconvenient in some cases. Furthermore, the above will be explained. In the conventional electronic length measuring device, in order to display both of the above-mentioned values, it was necessary to form slits for two specifications, inches and millimeters, on the conversion scale, as shown in FIG. In Figure 4, the optical conversion scale 1 has a pitch of 20 [micrometers].
Milli-inch 2a and pitch 1 [mm-inch]
(=25.4 [micrometers]) inch slit 2b is formed, and depending on the selection of the changeover switch 11, a substantially sine wave with a pitch of 20 [micrometers] or a pitch of 1 [milliinch] is input to the shaping circuit 12. Ru. Although the input wave has two phases, it is shown as one phase in the drawing. After this input wave is shaped, it is divided into, for example, 20 parts by the dividing circuit 14, and the pitch is 1.
A negative logic display signal pulse of [micrometer] or 0.05 [milliinch] is generated. These pulses pass through an inverting circuit 18 to a count display 20.
After inputting it into the , it is counted and displayed with a resolution of 1 [micrometer] in millimeter display and 0.05 [milliinch] in inch display. In the case of such a conventional electronic length measuring device, the conversion scale 1
Two types of slits in inches and millimeters 2
a, 2b had to be formed. Forming such a slit makes it difficult to process the conversion scale, increases the size of the conversion scale, and increases the price of the length measuring device. Further, as another means for obtaining the above two types of display, it is also possible to obtain other display values by multiplying the display value in units of inches or millimeters by a certain coefficient. However, in this case, even when switching from inches to millimeters, 1 [inch] is 25.4.
Since it is [millimeters], the number of digits displayed is 6 decimals.
When using digits, a multiplier for 6 decimal digits and 3 decimal digits is required to switch the display, which increases the size of the electrical equipment and makes it impractical due to price. In addition, as mentioned above, when displaying in millimeters by multiplying the displayed value in inches by a certain coefficient, the signal from the optical conversion scale with a slit for inches only is processed, and once the value can be displayed in inches, Since the calculation is performed by multiplying the signal by a coefficient and the calculation is completed, it is displayed in millimeters, so there is also the problem that the millimeter display is always delayed by the calculation time compared to the inch display. It was hot. If there is such a problem, for example, when using this digital display measuring instrument to detect and display the feed rate of cutting tools of machine tools,
When machining parts that are expressed in millimeters and parts that are expressed in inches alternately on a drawing, in millimeters, the count value is sampled at a certain period of time to make the count value that can be expressed in inches, and from this count value. Because of the conversion, the actual tool feed amount may differ from the displayed value. Therefore, when the machining accuracy is high, the tool may be erroneously fed too much. For this reason, it is desirable that the time from sampling to display be the same for both millimeters and inches. The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a digital display that can display both inch and millimeter units based on a signal obtained from a conversion scale having only one type of slit. The purpose is to provide display measuring instruments. [Means for Solving the Problems] In order to achieve the above object, the present invention includes an encoder that has a conversion scale engraved with an inch scale and outputs an electrical signal when moved relative to the object to be measured. , processing the electrical signal from the encoder to generate 5×10 ⁿ
(n is a negative integer. The same shall apply hereinafter.) A conversion gate circuit consisting of a dividing circuit that outputs inch-pitch pulses and an OR gate so that the pulse from the dividing circuit is supplied to one input terminal. and,
The conversion constant "27×10 ⁿ " is used during up counting only when the millimeter display signal is applied.
an addition circuit that integrates the conversion constant ``73 x 10 <sup>n</sup> '' at the time of down counting, and a carry signal generation circuit that detects when the integrated signal of the addition circuit exceeds ``100 x 10 ⁿ ''. and a millimeter conversion pulse generation circuit that supplies the output from the carry signal generation circuit as a millimeter conversion pulse to the other input terminal of the OR gate constituting the conversion gate circuit, and counts the output pulses from the conversion gate circuit. In the inch display state, the display has a resolution of 5×10 ⁿ inches, and in the millimeter display state, the display has a resolution of 100×10 ⁿ millimeters. [Function] The electrical signal from the encoder has a conversion scale engraved on an inch scale and outputs an electrical signal when it is moved relative to the object to be measured, and the split circuit processes the electrical signal.
×10 ⁿ (n is a negative integer. The same shall apply hereinafter.) Output pulses with an inch pitch. The pulse from the dividing circuit is supplied to one input of the OR gate of the conversion gate circuit. On the other hand, the addition circuit uses the conversion constant "27×
10 ⁿ '' and, at the time of down counting, a conversion constant of ``73×10 ⁿ ''. A signal detected by a carry signal generation circuit that detects that the integrated signal of the adder circuit has become 100×10 ⁿ or more is supplied as a millimeter conversion pulse to the other input terminal of the OR gate constituting the conversion gate circuit. do. The output pulses from the conversion gate circuit are counted and displayed by the counting display circuit at a resolution of 5×10 ⁿ inches in the inch display state and at a resolution of 100×10 ⁿ mm in the millimeter display state. [Embodiments] Preferred embodiments of the present invention will be described below based on the drawings. FIG. 1 shows the circuit block configuration of a digital display measuring instrument used in the present invention. The encoder 10 including the optical conversion scale 1 with inch slits 2b for extracting the detection signal from the object to be measured can be of various types, and of course it is also possible to use detectors other than optical detectors. . Detection signal waveform shaping circuit 1 of encoder 10
2, the input signal is divided into a predetermined number by the dividing circuit 14, and the input signal is divided into a predetermined number of inch signal pulses 14.
a, 14b are generated. Here, 14a indicates an up pulse, and 14b indicates a down pulse. This inch signal is converted into the inch-millimeter conversion circuit 1 according to the present invention.
6 selects the inch specification or millimeter specification, and passes through the inversion circuit 18 to the count display circuit 20.
sent to. A characteristic feature of the present invention is that the signal detected by the encoder 10 is in inch scale. Furthermore, the pitch of the inch signal pulses supplied from the dividing circuit 14 to the inch-millimeter conversion circuit 16 is set to 50 [microinches]. In this case, the display when converted into millimeters is 1 [micrometer]. In the following explanation, the pitch of the inch signal pulse is 5×10 ^-5 [inch]. In this way, in the present invention, since the detection signal from the encoder 10 uses inch signal pulses, when displaying inches, the inch-millimeter conversion circuit 16 simply converts the inch signal pulses from the dividing circuit 14 through a negative logic OR gate. It is sufficient to simply pass it through the inversion circuit 18. In this case, the outputs 17a and 17b of the millimeter conversion pulse supply circuit 17 are fixed at high level, and the display signal pulses 26a and 26
b is the same as the inch signal pulses 14a and 14b, so the count display 20 has a resolution of 5.
Can be displayed in ×10 ^-5 [inches]. Next, when millimeter display is required, an appropriate correction pulse may be supplied from the millimeter conversion pulse supply circuit 17 in addition to the inch signal pulses 14a and 14b. A circuit including two negative logic OR gates connected to the inversion circuit 18 is referred to as a conversion gate circuit 26. It is important that there is a relationship between inch and millimeter units, where 1 [inch] equals 25.4 [mm]. That is, this means that when the millimeter is used as a standard, the unit millimeter, that is, the inch amount corresponding to 1 [millimeter] is an indivisible value. Therefore, in the present invention, inch signal pulses are used as input signal pulses. If a pulse in units of inches is used as a reference, pulses in units of millimeters can be obtained by adding a correction pulse to the reference pulses. In the present invention, the inch signal pulse is 5×10 ⁿ
The inch pitch has the advantage of facilitating calculation processing when obtaining millipulses. This calculation process will be described below. Here, the table below shows the values when m×10 ^-5 [inch] (1≦m≦9) is converted into millimeter units. Let us consider a case where a signal with a pitch of 1×10 ⁻⁵ inches is used as the inch signal pulse 14a to display in millimeters. The inch signal pulse is shown in FIG. 5A. From the conversion table below, 1×10 ^-5
An inch pitch pulse is considered to be a pulse with a pitch of approximately 2 x 10 ^-4 millimeters.

【table】

〔Effect of the invention〕

As explained above, according to the present invention, the electrical signal from the encoder, which has a conversion scale engraved on an inch scale and outputs an electrical signal when it is moved relative to the object to be measured, is processed to 10 ⁿ (n is a negative integer)
In addition to outputting inch pitch pulses, only when the millimeter display signal is applied, the conversion constant ``27 x 10 <sup>n</sup> '' is integrated during up counting, and the conversion constant ``73 n'' is integrated during down counting.
×10 ⁿ ”, the accumulation signal of the adder circuit is
10 ⁿ '' or more is added to the 5 x 10 ⁿ inch pitch pulse, and one of these output pulses is counted to obtain a resolution of ``5 n'' in inch display mode.
× 10 ⁿ ” inches, and in the millimeter display state, it can be displayed with a resolution of 100 × 10 ⁿ ” millimeters, so the conversion between inches and millimeters requires a complicated calculation circuit that multiplies the conventional inch display by a coefficient. This can be easily done using a simple conversion circuit without requiring a 100% conversion circuit, and there is an advantage that the time required from measurement to display is the same whether it is displayed in inches or millimeters since the calculation time required in the conventional method is not required. Further, according to the present invention, since a conversion scale with only inch scales is sufficient, there is an advantage that a conversion scale with complicated processing steps as in the conventional case is not required. In addition, according to the present invention, inch signals are simply passed through as is, while inch pulses are used for millimeter signals, and additional millipulses are supplied at predetermined times, so the multiplication circuit is In addition to being unnecessary, the integration of fractional numbers can be done with a two-digit integration circuit, which has the advantage of simplifying the circuit configuration.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the digital display measuring instrument of the present invention, Fig. 2 is a circuit diagram showing the circuit configuration of the inch-millimeter conversion circuit which is the main part of the invention, and Fig. 3 is the inch-millimeter conversion circuit of Fig. 2. A time chart is shown to explain the conversion operation. Fig. 4 is a block diagram showing a conventional digital display measuring instrument. Fig. 5 is a diagram showing the case where the present invention is applied to a case where the inch signal pulse is 1 x 10 ⁿ pitch. This is a time chart showing the relationship with output pulses. 16...inch-millimeter conversion circuit, 26...conversion gate circuit, 48...number circuit, 50...arithmetic circuit, 52...buffer memory, 56...millipulse FF, 74...millipulse gate circuit, 76...
...Carry signal circuit.

Claims (1)

[Claims] An encoder has a conversion scale engraved on a 1-inch scale and outputs an electrical signal when it is moved relative to the object to be measured, and an encoder that processes the electrical signal from the encoder and converts it into a 5× ¹⁰ A conversion gate circuit consisting of a dividing circuit that outputs pulses with inch pitch (an integer of When counting up, the conversion constant ``27 x 10 <sup>n</sup> '' is accumulated, and when counting down, the conversion constant ``73 x
10 ⁿ '', a carry signal generation circuit that detects when the accumulated signal of the addition circuit exceeds 100 x 10 ⁿ , and converts the output from the carry signal generation circuit into the above-mentioned conversion. A milli-conversion pulse generation circuit supplies milli-conversion pulses to the other input terminal of the OR gate constituting the gate circuit, and the output pulses from the conversion gate circuit are counted and the resolution is "5 x 10 ⁿ " inches when displayed in inches. , a digital display measuring instrument having a counting display circuit capable of displaying each millimeter with a resolution of ``100 x 10 ⁿ '' in the millimeter display state.