CN1081108C - New usage of absolute optoelectronic encoder - Google Patents

Abstract

The present invention solves the problem that an absolute type photoelectric encoder automatically carry and borrow from a reversible counter when a rotary angle is greater than one circle, so that long-distance detection can be realized without connecting more than two encoders by a reduction gear, and gear clearance errors do not exist. If widely used for the position detection of numerical control machines, the method has obvious economic benefits. The method is carried out technically by a logic circuit.

Description

A kind of new using method of absolute optical encoder

The invention belongs to the method invention

The essential position detection with high accuracy element that relies on of high-precision numerically-controlled machine is as grating, inductosyn etc.But these high-precision test elements are subjected to detecting the restriction of length again, thus in the numerically-controlled machine of precision widespread use binary channels and even multichannel method for detecting position.As rotary transformer and the thick smart position detector of induction with the synchronizer composition, but this multicenter detecting method complex structure cost height.And incremental optical-electricity encoder is easy to generate cumulative errors, is difficult to realize long distance detecting.In sum, the various methods that are used for the numerically-controlled machine position probing all do not have to solve well the contradiction between high-precision requirement and the large scale processing.Absolute value formula photoelectric encoder is a kind of high-precision position angle detecting element, compares with the increment type grating detection component, and it does not have cumulative errors, can adapt to run up, can be because of not having a power failure and other reason generation coordinate figure removing.Shortcoming is need do special processing when revolution changes greater than one, with reduction gearing a plurality of scramblers is linked up usually.It is more that this mode is used for long distance detecting problem, except there is the gear clearance error again in complex structure cost height, so absolute value formula photoelectric encoder is not used widely.

The new using method of the absolute value formula photoelectric encoder of introduction of the present invention has solved when its revolution changes greater than one the problem to up-down counter automatic carry and borrow, thereby must not connect plural scrambler with reduction gearing again and just can realize that long distance detects, reduce the gear clearance error simultaneously and improved accuracy of detection, had fairly obvious good effect.Be the technical scheme that realizes this effect below.

From prior art as can be known absolute optical encoder generally adopt reflected code, by the direct reading of opto-electronic conversion, become binary code with logical circuit.If scrambler is 64 calibration, then the result after logical conversion is six binary codes, as the A among Fig. 1 ₅A ₀A among Fig. 1 ₅A ₀The up/down binary counter (rough schematic view) formed by 8 triggers of the left side.At A ₅A ₄Left upper end and what link with it is double figures sign indicating number register, and A ₃A ₂The switching of state logic decision register input gate, work as A ₃A ₂The input gate that is 10 o'clock registers is just opened, and is both-end input digital register owing to what select for use, so do not need reset in advance.When numerically-controlled machine was worked, the input gate of 16 calibration registers of scrambler revolution was just opened once, with A ₅A ₄Value be stored in the register.Use A ₅' A ₄' represent to be stored in the value in the register, analyze the A of lathe when work now ₅' A ₄The meaning that ' value is represented.

As A ₅' A ₄' value is 01 or 10 and shows that scrambler neither can overflow does not need borrow, because dyadic number A at this moment before the register input gate is opened next time yet ₅A ₀Be to add or deduct the problem that dyadic number 10000 can not produce borrow or carry.That analyze consideration is A ₅' A ₄' be 00 and 11 o'clock both of these cases.

A ₅' A ₄' value be 00, be out of question to worktable advancing, as worktable when retreating then the presentation code device be about to the up-down counter borrow and the moment of borrow A just ₅A ₄By 00 upset is that time of 11, therefore available A ₅', A ₄', A ₅, A ₄State form the borrow logic.If A ₅' A ₄' value be 11, be no problem to worktable retreating, if worktable advancing, then the presentation code device is about to the up-down counter carry, the time of carry is A ₅A ₄Become for that time of 00 by 11, be still this moment uses A ₅', A ₄', A ₅, A ₄State form carry logic.

Comprehensive above the analysis is by A ₅', A ₄', A ₅, A ₄State form borrow carry signal logical circuit such as Fig. 2.As can be seen from the figure:

Carry signal $E=A_5^{\′}{A}_4^{\′}\stackrel{-}{A_5}\stackrel{-}{A_4}$

The borrow signal $F=\stackrel{-}{A_5^{\′}}\stackrel{-}{A_4^{\′}}{A}_5{A}_4$

A here ₅, A ₄Be scrambler at the exact value that produces at once, and A ₅', A ₄' be A ₅, A ₄Reference point, logical circuit is that the two state of contrast is lent the carry judgement.

Be noble potential at the moment of carry E end, by or the door and with door G still be noble potential, but the not gate output valve that links to each other with the G output terminal becomes 0 by 1, sealed the input end of G through the RC time-delay, so the output terminal of G gets back to 0 again, so G output is a positive pulse, becomes the carry pulse of scrambler to up-down counter.Also complete class is same therewith in the formation of borrow pulse, and the carry status of borrowing of up-down counter is controlled by the discriminating direction circuit in the numerical control arithmetic unit, RC time constant decision pulse width.

Also have the problem that will note at last, if after carry or borrow, worktable has changed sense of displacement immediately, immediately borrow or carry, at this moment A again ₅' A ₄' be still carry or borrow value before, can't carry out borrow or carry again.Therefore must open A with carry (borrow) pulse of G output in that time of carry or borrow ₅' A ₄' input gate is with A ₅A ₄Value (11 or 00) be input to A ₅' A ₄In ' the register.As seen G must have bigger promotion power.But work as A ₅A ₄Be input to A ₅' A ₄Behind ' the register, because A ₅', A ₄' state change, borrow (carry) pulse returns 0 immediately, its pulsewidth is only several+ns about, this may be not enough to the up-down counter of being made up of the multidigit trigger, therefore be among Fig. 3 at total logical diagram, increased a tie line that plays positive feedback effect Fig. 1 and Fig. 2 merging.When E or F return still keep after 0 or the noble potential of gate output terminal N up to the input off level that C is discharged to G, borrow (advancing) digit pulse just to return 0.Whole DLC (digital logic circuit) shown in Figure 3 can be divided into three relatively independent parts, on the left side of borrowing carry signal E, F, be to borrow the carry signal logical circuit, by last angle is to borrow carry pulse to form and output circuit, and second figure is to borrowing the carry signal logical circuit that the digital register and the input gate control circuit thereof of reference point are provided.

When absolute optical encoder was used to measure cloth length or elevator and has the records of distance by the log, borrowing carry pulse to form with output circuit can be divided into two-way output from E, F.Each road is all mixed in the same old way or door, with door and interlock circuits such as RC time-delay, at this moment borrow, carry pulse just separated, the back connects the bidirectional reversible counter and get final product, but attention all will be opened A by means of carry pulse ₅', A ₄The input gate of ' register, that so need the number of winning the confidence remove to control up-down counter has borrowed carry status.

The up-down counter that 8 triggers among Fig. 3 are formed stores the high-value of tested length, and A ₅A ₀Show its low-value, if each calibration of scrambler is represented the displacement of one of worktable, then tested maximum range reaches 16.384cm.If run into power failure in the time of in this way, the value that up-down counter is deposited is eliminated, can take following method, in actionless track adjacent or the other length scales of inscribing of surface of contact with worktable, with scrambler one circle range is minimum scale, so just can observe with the naked eye the value of depositing in the up-down counter, use the method for manually importing to recover the length value that is eliminated then, and with A ₅A ₄Be input in the register, this will increase corresponding circuit and plate bond switching certainly.

The new using method of absolute optical encoder is compared with the multistage code-disc method that connects with reduction gearing, because improved accuracy of detection, has increased the detection range, and result of use obviously is better than the latter; Also cheap many from price, on electric utility, increased some parts and physical construction has been saved complicated reduction gearing and multistage code-disc, this is the developing direction of electromechanical integration just also.Because the use of numerically-controlled machine is very general, so the present invention has very wide application prospect.

Claims (3)

1. one kind can make the on-stream using method to up-down counter automatic carry and borrow of absolute optical encoder, adopt DLC (digital logic circuit) to realize technically, it comprises by means of carry signal logical circuit, digital register and input gate control circuit thereof, borrows carry pulse to form and output circuit, the invention is characterized in: all signals of controlling whole DLC (digital logic circuit) operation all are the number values of taking from the continuous variation of the on-stream generation of this scrambler, and do not take any signal in addition.

2. according to claim 1ly can make the on-stream using method of absolute optical encoder, form that to borrow the state of carry signal logical circuit be the number value A of the on-stream generation of scrambler to up-down counter automatic carry and borrow ₅, A ₄, A ₅', A ₄', it is characterized in that: as borrowing carry logic to judge the A of reference point ₅', A ₄' be respectively A ₅, A ₄Before be stored in the register value in the digital register.

3, according to claim 2ly can make the on-stream using method of absolute optical encoder, A to up-down counter automatic carry and borrow ₅', A ₄The input gate of ' digital register is the number value A by the on-stream generation of scrambler ₃, A ₂Under the logic state of setting, open, or by borrowing carry pulse to open, the former guarantees that scrambler revolution 1/4 encloses input gate and just opens once that the latter is in order to make whole DLC (digital logic circuit) by the requirement operation of borrowing carry.

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