JPS63111409A - Deciding method for origin signal - Google Patents

Abstract

PURPOSE:To decide an origin signal correctly by deciding a level signal which is generated after a signal right before a moving body in reciprocal motion reaches its stroke end as the origin signal. CONSTITUTION:A scale signal (a) which is inputted to a pulse counter 9 through a scale sensor is branched and inputted to a signal discriminator 21 to judge and store whether the last signal (a) is on a up-pulse side or down-pulse side. A signal (g) sent out of the signal discriminator 21 goes up to 'H' level at the point of time when a cylinder head 1 begins to move from a forward movement side end stroke position to a backward movement side end stroke position. Even when an origin signal (b) contains noises, the output signal (g) of the signal discriminator 21 never goes up to the 'H' level, so an origin position signal (h) sent out of an AND gate 22 never rises to the 'H' level and data is not rewritten in a pulse counter 9.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an incremental method installed in processing machines such as die-casting machines and injection molding machines to measure the position and speed of the cylinder rod of the operating cylinder. The present invention relates to an origin signal determination method suitable for use in determining an origin signal sent out by a magnetic scale.

[Conventional technology]

2. Description of the Related Art Conventionally, die-casting machines and the like have used a movement position detection device using a magnetic scale to determine the movement position of a cylinder rod of an operating cylinder thereof. FIG. 4 is a block configuration diagram thereof. That is, the striker 3 is fixed to the cylinder rod 1 by the fixing fitting 2, and the movement of the cylinder rod 1 is transmitted to the striker 3. A magnetic scale 6 and an origin magnet 4 are fixed to the striker 3. The magnetic scale 6 is magnetized for each unit distance, and is designed to be able to transmit an electric signal for each unit distance when combined with the scale sensor 7. Further, the origin magnet 4 is designed to be combined with the origin sensor 5 to transmit an rHJ level electrical signal. That is, the scale sensor 7 and the origin sensor 5 are fixed to a machine base (not shown) so as to always maintain equal intervals with respect to the movement of the striker 3, and the scale sensor 7 and the origin sensor 5 are fixed to a machine base (not shown) so as to always maintain equal intervals with respect to the movement of the striker 3. 7 transmits a pulsed electric signal (hereinafter, this electric signal is referred to as scale signal a), and the origin sensor 5 transmits an "H" level origin signal at the point where it coincides with the origin magnet 4. There is.

The scale signal a generally needs to be in the form of a signal representing the moving direction and unit distance of the striker 3, and for example, an up-down pulse signal system is adopted. In other words, the up-down pulse signal system has two signal output series and has a function of transmitting a pulse signal every unit distance movement, and the transmitted pulses are divided into the two signal output series according to the direction of movement and sent to the outside. The signal output series is divided into two series, an up pulse signal and a down pulse signal, depending on the direction of increase/decrease of the count value in the pulse counter that inputs the signal output. That is, the fourth
In the figure, when the striker 3 moves from the right side to the left side in the figure, the scale signal a sent from the scale sensor 7 is used as an up pulse signal, and the count value in the pulse counter 9 is added by the number of input pulses by this up pulse signal. It is now possible to do so. In addition, when the striker 3 moves from the left side to the right side, the scale signal a sent from the scale sensor 7 is used as a down pulse signal, and the count value in the pulse counter 9 is subtracted by the number of input pulses by this down pulse (). In addition, the pulse counter 9 inputs the origin signal S via the origin sensor 5, receives the data C set in the origin data setter 8 by inputting the origin signal S, and inputs the data C set in the origin data setter 8. The internal data is corrected. That is, at the time when the origin signal of rHJ level is generated, the count value of the pulse counter 9 is equal to the data C.
It can now be rewritten as .

Further, the pulse counter 9 always uses the internal count value as the data signal d to the comparators 111, 112, . . .
・Comparators 111 and 112 are configured to send to IIN.
...IIN is the comparison data setter 101.102...
・e1+e set in ION! ...The comparison standard data eN is input, and these comparison standard data 61+e!
. . . eH and the data signal d from the pulse counter 9 are compared and calculated. That is, comparator 11
1゜112・--11N, e1≧d, e2≧d
. . . A comparison operation of eH≧d is performed, and output signals f, , f, . . . fs are output as logical value data.

[Problem that the invention seeks to solve]

However, the factory environment where processing machines such as die-casting machines and injection molding machines are installed is not necessarily good.
Electric welding is performed near a processing machine that is in operation, and noise is often generated by turning on and off the power of auxiliary equipment.

When the above-mentioned moving position detection device is installed in such an environment, it goes without saying that sufficient noise countermeasures are required, but there are limits to this, and if external environmental conditions worsen, the origin sensor 5 Noise corresponding to the origin signal sent out by the pulse counter 9 may be input to the pulse counter 9.

In other words, if such noise is input to the pulse counter 9, the count data in the pulse counter 9 will be rewritten to the data C set in the origin data setter 8 at the time the noise is input, and from then on There was a risk that an error would occur in detecting the moving position of the cylinder rod 1, leading to a serious accident.

[Means for solving problems]

The present invention has been made in view of these problems, and includes a means for transmitting a last-minute signal before reaching the stroke end from the forward side to the backward side of a moving body that performs reciprocating motion, and a last-minute signal sending means for sending the last-minute signal. an origin signal transmitting means for transmitting an origin signal after the immediately preceding signal is transmitted by the transmitting means until the moving body reaches its stroke end, and the origin signal is generated after the immediately preceding signal is transmitted by the immediately preceding signal transmitting means. A signal with a level corresponding to , is determined to be the origin signal.

[Effect]

Therefore, according to the present invention, even if a noise signal of a level equivalent to the origin signal is generated until the moving object reaches the end of its stroke from the forward side to the backward side, the signal is mistakenly recognized as the origin signal. There is no judgment.

〔Example〕

Hereinafter, the origin signal determination method according to the present invention will be explained in detail. FIG. 1 is a block diagram showing an embodiment of a cylinder loft movement position detection device to which the origin signal determination method according to the present invention is applied. In this figure, the same reference numerals as in FIG. 4 indicate the same constituent elements, and the explanation thereof will be omitted. In the figure, 21 is a signal discriminator, and 22 is a three-man power AND gate. The signal discriminator 21 is configured such that the scale signal a, which is input to the pulse counter 9 via the scale sensor 7 shown in FIG. ) is on the up-pulse signal side or the down-pulse signal side is judged and stored in the signal discriminator 21. In this embodiment, the immediately preceding scale signal a is on the down-pulse signal side. The output signal g at the rHJ level is sent out only when this is the case. Further, the comparator 111 is configured to send out an output signal f at the "H" level when e1≧d is established within the comparator 111, and the output signal r sent out by the comparator 111 is The output signal g sent out by the device 21 and the origin signal g sent out by the origin sensor 5 in FIG. 4 are respectively input to the AND gate 22. The output of the AND gate 22 is input to the pulse counter 9 as the origin position signal, and the pulse counter 9 sets the origin data when the origin position signal of the "H" level is input. The data C set in the device 8 is taken in and the internal data is rewritten.

Next, the operation of the cylinder loft movement position detecting device configured as described above will be explained using FIG. 2. That is,
FIG. 2(a) shows the cylinder loft 1 in FIG. This is a diagram showing the relationship between stroke position and time when reciprocating between the stroke positions (referred to as stroke positions), with time t on the horizontal axis and stroke position S on the vertical axis.
It shows t. The zero point of the stroke position shown in the figure is the backward end stroke position, and the max point is the forward end stroke position. In other words, the cylinder rod 1 is moved forward at a constant speed from the backward end stroke position to the forward end stroke position, and after stopping Δ for a time, it is moved back at a constant speed from the forward end stroke position to the backward end stroke position. represents the state. The relationship diagram of the stroke position of the cylinder loft 1 with respect to time is equivalent to the increase/decrease characteristic of the data signal d input to the pulse counter 9 with respect to time. That is, elm and s written together on the vertical axis of FIG. 2 (al) indicate the stroke position and
This shows the stroke position at which the origin signal at HJ level is sent.

2(G)) and (C) show the scale signal a manually input to the signal discriminator 21 and the pulse counter 9,
When the cylinder rod 1 is in a state of movement from the backward end stroke position to the forward end stroke position, the second
Up pulse signal a shown in figure (b).

is in a state of movement from the forward end stroke position to the backward end stroke position, a down pulse signal a2 shown in FIG. 2(C) is input to the signal discriminator 21 and the pulse counter 9. Figure 2(d) shows the signal discriminator 2.
This is the output signal g sent out by No. 1, and reaches the rHJ level from the time the cylinder rod 1 begins to move from the forward end stroke position to the backward end stroke position. In addition, in FIG. 2 (el is the output signal f sent out from the comparator 111
, and when e, ≧d holds, the rHJ level is reached.

FIG. 2(f) shows the origin signal sent by the origin sensor 5, which is at the rHJ level while the origin sensor 5 and the origin magnet 4 are in agreement.

Now, it is assumed that the origin signal shown in FIG. 2 (fl) is superimposed with noise of 2. to 26 as shown in FIG. , noise Z l ” Z &, the pulse counter 9 rewrites its count data to the data C set in the origin data setter 8, and thereafter the up pulse signal a
, and down pulse signal a2 are counted. That is, the data signal d sent out by the pulse counter 9 is as shown by the solid line in FIG. 2 (hl).However, in the apparatus shown in this embodiment, as shown in FIG. 7%, no longer affected by 24.

In other words, in order to correctly stop the cylinder loft 1 at its backward end stroke position, it is necessary to cut off the hydraulic pressure in advance due to a delay in the hydraulic circuit or the inertia of the cylinder, and this hydraulic cutoff signal is usually used to determine the backward end stroke position. The output signal f sent out from the comparator 111 immediately before reaching . In other words, even if the origin signal shown in Fig. 2 (g) with superimposed noise occurs while the cylinder loft 1 is moving, the movement of the cylinder loft 1 from the backward end stroke position to the forward end stroke position When the signal discriminator 21 is moving, the output signal g sent out by the signal discriminator 21 cannot be at the rHJ level, so the AND gate 2
2, the origin position signal sent out does not reach the rHJ level,
Data in the pulse counter 9 is not rewritten. Furthermore, when the cylinder rod 1 moves from the forward end stroke position to the backward end stroke position, the output signal g sent out by the signal discriminator 21 is at the "H" level, but the output signal g sent out by the comparator 111 is output signal f,
However, as mentioned above, it does not reach the "H" level until just before the cylinder loft 1 reaches the backward end stroke position, so even during this time, the home position signal sent by the AND gate 22 does not reach the rHJ level, and the pulse Data in the counter 9 is not rewritten. After the output signal f sent out by the comparator 111 reaches the rHJ level, the noise superimposed on the origin signal is at the "H" level origin. ! (The output signal f1 sent from the comparator 111 is manually input to the pulse counter 9 as No. 8, but the output signal f1 sent from the comparator 111 is rHJ
Since the stroke from when the cylinder loft 1 reaches the level until it stops is very small, there is no actual damage. Furthermore, after the output signal f of the comparator 111 reaches the "H" level, noise that occurs before the generation of the "H" level origin signal, such as noise Zs, will be affected by the rHJ level origin signal. When the signal is input, the pulse counter 9
Data C is set to , and eventually its influence on noise disappears. Also, like the noise shown in z6,
For noise that occurs later than the origin signal at the "H" level, noise 2. Since the data C is entered into the pulse counter 9 at the time when the data C is input, the detected stroke position will be slightly larger than the actual stroke.

In other words, it is better to bring the origin signal originating position from the origin sensor 5 as close as possible to the backward end stroke position, thereby reducing actual damage and improving reliability.

In this embodiment, the output signal f, which is a hydraulic cutoff signal for the cylinder rod 1, is input to the AND gate 22, but it does not necessarily have to be a hydraulic cutoff signal for the cylinder loft 1; Any other signal may be used as long as it is sent immediately before reaching the backward end stroke position. In other words, it is desirable that the immediately preceding signal that is sent out immediately before reaching the backward end stroke position is obtained at a position as close to the backward end stroke position as possible, and the interval between the generating position of the immediately preceding signal and the backward end stroke position is By narrowing the
The influence of noise superimposed on the origin signal can be further reduced, making it possible to detect the moving position of the cylinder loft with higher reliability.

Furthermore, with the configuration shown in FIG. 3, the influence of noise that occurs after the origin signal is generated, such as the noise z6 shown in FIG. 2(g), can be canceled during the next forward movement of the cylinder rod 1. can. That is, in FIG. 3, 21a is a signal discriminator that discriminates down pulses of the input scale signal a and sends out an rHJ level output signal g, and also discriminates up pulses and outputs an rHJ level output signal g1. It is set to be sent. Also, 20
Reference numeral 1 denotes a data discriminator, which uses the data signal d sent out by the pulse counter 9 in FIG. y
is now entered. That is, data discriminator 2
01 determines and stores whether or not the value of the input data signal d is zero based on the input of the determination signal y, and when it is determined that the value is not zero, outputs the rHJ level output signal j to one end of the AND gate 203. The other end of the AND gate 203 receives an rHJ-level forward command X that urges the cylinder loft to move forward. With this rHJ level forward command X,
It goes without saying that the cylinder loft begins to advance from the backward end stroke position to the forward end stroke position. Then, the rHJ level logic output k sent out by the AND gate 203 is input to the switch circuit 202 as a switching signal, and the switch circuit 202
The J-level switching signal k switches the input of the output signal g to the AND gate 22 to the output signal g.

With such a circuit configuration, it is determined whether the count data in the pulse counter 9 is zero at the backward end stroke position, and if it is not zero, the next forward end stroke position is determined as an exception. When the cylinder loft is moved to the stroke position, the rHJ level origin signal passes through the AND gate 22 and is input to the pulse counter 9 as the origin position signal.
The count data at is rewritten to a normal value (data C). The data discriminator 201 and the switch circuit 202 are configured so that the origin position signal sent from the AND gate 22 is input as a reset signal.
The output signal j and switching signal k are reset.

〔Effect of the invention〕

As explained above, according to the origin signal determination method according to the present invention, there is provided a last-minute signal sending means for sending a last-minute signal before a moving body that performs reciprocating motion reaches the stroke end from the forward side to the backward side; an origin signal transmitting means for transmitting an origin signal after the immediately preceding signal is transmitted in the means and before the moving body reaches its stroke end; Since a signal at a level equivalent to the origin signal is determined to be the origin signal, even if a noise signal at a level equivalent to the origin signal occurs, it is ignored until the moving object reaches the end of its stroke from the forward side to the backward side. A signal is not erroneously determined to be an origin signal, and the influence of noise superimposed on the origin signal can be significantly suppressed.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing an embodiment of a cylinder loft movement position detection device to which the origin signal determination method according to the present invention is applied, and FIG. 2 is an operation of this movement position detection device. FIG. 3 is a block diagram showing another embodiment of this moving position detecting device, and FIG. 4 is a block diagram showing a conventional moving position detecting device. 1...Cylinder loft, 4...Origin magnet, 5
... Origin sensor, 6... Magnetic scale, 7... Scale sensor, 8... Origin data setter, 9... Valscaventa, 101-1ON... Comparison data setter, 111-11N. ... Comparator, 21... Signal discriminator, 22... AND gate.

Claims (1)

[Claims] Immediately before a moving body that performs reciprocating motion reaches a stroke end from a forward side to a backward side, an immediately preceding signal sending means sends an immediately preceding signal; and after the immediately preceding signal sending means sends an immediately preceding signal, the moving object reaches its stroke end. and an origin signal sending means for sending out an origin signal until the origin signal is reached, and a signal of a level corresponding to the origin signal generated after the immediately preceding signal is sent by the immediately preceding signal sending means is determined to be the origin signal. An origin signal determination method characterized by the following.