Abstract: A control system for a programmable control device (10) executing a user program cyclically, wherein a data bit is provided in a memory space which can be accessed by a user program, the data bit is made "ON" in an operation mode and made "OFF" in a stop mode. The data bit is programmed with an AND condition for an output signal (Q1) to be made "OFF" in the stop mode, and the operation mode is shifted to the stop mode only after having made the data bit "OFF" and having executed the user program for one or more scans.

Abstract: A numerical control device adapted to control a plurality of transfer machines mounted on a transfer line. The numerical control device is composed of an NC section (13) for controlling the axes of the transfer machines and a PMC section (14) for executing sequence control. The PMC section (14) reads current position data from a current position register (16) of the NC section (13) through a window, and compares the read data with previously set zone data (19). A function instruction (18a) delivers the result of the comparison as a zone signal, and executes a modification control of an execution sequence by using the zone signal. Therefor, a high-accuracy region signal can be set.

Abstract: A simulation method for a programmable controller (PC) is provided in which a ladder program (22) of a PC is simulated. A cursor (1) is set at a relay contact on a screen (42a) displaying the ladder program (22) to directly change the input signal. A logical process is performed on the input signal (5) and an input signal (6) from a machine to simulate the ladder program (22). By setting the cursor at a contact to be changed on the ladder program and operating the software keys, a simulation of the ladder program corresponding to actual machine movements can be executed. Since the input can be changed directly on the ladder program, the simulation can be efficiently performed.

Abstract: A programmable controller according to the present invention has memory means (P) for registering any functional instruction. On the basis of a functional instruction stored in the memory means, an individual functional instruction (Func) is repeatedly output to a machine tool. When the format of a functional instruction changes due to a difference in input conditions, input condition (B, C) data are created as a ladder and, by executing a single fixed input condition (A), the lead address of an area storing the parameter of the individual functional instruction is called and output, whereby a functional instruction of a unified format is executed.

Abstract: An output torque of a servomotor is controlled to prevent overrun of an injection mechanism in an injection molding machine. The injection mechanism is driven by the servomotor to perform an injection operation of the injection mechanism. The injection molding machine includes a torque limit circuit which limits a value of a torque instruction output from a servo circuit of the injection mechanism operating in an injection direction to a value of a torque limit instruction from a numerical control apparatus and does not perform a torque limit operation of a drive instruction in a direction opposite to the injection direction. Therefore, the servomotor for driving the injection mechanism can be rapidly decelerated to prevent overrun of the injection mechanism.

Abstract: There is provided an initializing method for a programmable machine controller, whereby various control parameters of the programmable machine controller can be initialized quickly. The initial values of the various parameters, stored in a random access memory for initial-value setting of the controller, are transferred to a blank region of another random access memory for storage therein (S1.about.S4), and then transferred to a read-only memory (ROM) cassette for storage therein (S5). When a command for parameter initialization is delivered with the controller loaded with the ROM cassette, the various parameters are initialized using the initial values stored in the cassette.

Abstract: A numerical control method is provided which is capable of forming a circular are on a cylindrical surface of a cylindrical workpiece with high accuracy by the use of a simplified program. At first, a circumferential distance interval between the start and end points of a circular arc to be machined is calculated on the basis of a moving command value for a rotation axis indicative of an angular interval in the circumferential direction of the workpiece (S3). Then, a circular are interpolation processing is executed on the thus calculated distance interval and a moving command value for a linear axis indicative of an interval between the start and end points in the axial direction of the workpiece, to thereby calculate distribution amounts for the rotation and linear axes, respectively (S4).

Abstract: An injection molding machine wherein the values of variables for the current and several preceding molding cycles are displayed simultaneously, so as to perform process monitoring. Detection values of the variables in the current molding cycle are stored in a current value memory section of a memory (14). Every time a molding cycle ends, a CPU (11) transfers data from the current value memory section and past variable memory sections (which store the detection values of the respective variables of several preceding steps), to the past variable memory sections for the next preceding cycles. As a result the stored data of the memory sections is sequentially updated. The updated data and the current data are read out and displayed on a display unit (18).

Abstract: A signal tracing control system provided in a programmable machine controller (PMC) which controls a machine in response to a signal from a numerical control apparatus. A signal of a monitored RAM (1) is monitored for a change by a monitoring circuit (21). When a signal change is detected by the signal monitoring circuit (21), it applies a signal to a writing control circuit (22) which then writes the data of the monitored RAM (1) into a tracing buffer (2). This cycle of operation is repeated. Thus, only when a data item in the monitored RAM (1) is changed, is the signal traced. Effective signal tracing can therefore be effected with a small memory capacity.

Abstract: In a numerical control system for a machine tool using a general-purpose motor (11) in place of at least one of servo motors, a current position of a spindle (10) driven by the general-purpose motor (11) is detected (14, 9) and is compared with a position designated by a numerical control program. When the current position approaches the position designated by the numerical control program, brake signals (MBR, BR) are generated to brake the general-purpose motor (11) or the like, and a rotation signal (MCW, MCCW) of the general-purpose motor (11) is disabled, thereby stopping the general-purpose motor (11) so as to cause the spindle (10) to stop at the position designated by the numerical control program.

Abstract: A numerical control method of a numerical control unit according to the present invention includes automatically accessing external memory means 2--2 in a case where a desired NC program does not exist in an internal memory (2--2), reading the desired NC program, which is stored in the external memory means (4), into the internal memory (4), and executing the desired NC program. Accordingly, the operator need not go to the trouble of manually searching for a desired NC program and manually storing the program in the internal memory.

Abstract: The present invention relates to a method of restoring a rotary axis to a reference point. A workpiece coordinate system serving as a programming reference with respect to a machine coordinate system is decided, numerical control (NC) program data are created including at least NC data specifying an angle r between an origin (WR) of the workpiece coordinate system and a reference point (MR) in the machine coordinate system, and rotational direction positioning data based on the workpiece coordinate system, and a rotary axis is positionally controlled based on the NC program data. The method includes updating present positions Pm, Pw of a fixed point Q on a rotary axis (11) in the machine coordinate system and workpiece coordinate system in dependence upon rotation of the rotary axis, obtaining an angle a that satisfies the equationsPm=360.multidot.n+a, Pw=360.multidot.n+a-rin response to a reference point restoration command, then rotating the rotary axis by .vertline.a.vertline..sup.

Abstract: A numerical control apparatus (10) having an overtravel check function, includes a central processing unit (11), periodically performs pulse distribution, adds an amount of distribution to a present machine position stored in a present machine position register (R2), and checks whether the sum value falls within a preset moving range of a machine. If the value falls within the moving range, the amount of distribution is output and added to the present machine position register (R2) to update the machine position. On the other hand, if the value falls outside the moving range, a corrected amount of distribution obtained by subtracting the present machine position from the overtravel preset value is output and added to the present machine position register (R2) to update the present machine position.

Abstract: A numerical control system has a tool holder which supports tools . . . attached to at least two intersecting sides, preferably three sides of a rectangular shape. The tool holder is movable along plural axes, e.g., X and Y-axis directions. A memory circuit is provided for storing the positional data regarding the tips of the tools and a workpiece diameter when the tool holder is predetermined reference points. When a workpiece is to be machined by a selected tool, the data regarding the selected tool and the workpiece diameter are called from the memory circuit, the distance from the tool tip to the outer periphery of the workpiece is computed, and the tip of the tool is moved to the outer periphery of the workpiece. With this arrangement, tools can be changed quickly.

Abstract: The present invention provides a data transmission method for sending parallel data from a transmitting side to a receiving side. After transmitting an i-th item of data (DT.sub.i), the transmitting side sends a high-level data transmission signal (DS) to the receiving side at the expiration of a predetermined period of time (t.sub.1). In response to receipt of the high-level data transmission signal (DS), the receiving side reads the i-th item of data (DT.sub.i) and sends a high-level data reception signal (DR) to the transmitting side. The transmitting side ends the transmission cycle for the i-th item of data upon receiving the high-level data reception signal (DR). After transmitting the next or (i+1)th item of data (DT.sub.i+1), the transmitting side sends a low-level data transmission signal (DS) at the expiration of the predetermined period of time (t.sub.1). In response to receipt of the low-level data transmission signal (DS), the receiving side reads the (i+1)th item of data (DT.sub.

Abstract: A velocity control system for the injection shaft of an injection molding machine is adapted to drive an injection shaft (2") by an electric motor (20) and to control the electric motor (20) by a numerical control unit (30). The final position of the injection shaft (2") and the reference velocity of the injection shaft are commanded by data of a single block, and the velocity of the injection shaft (2") at each commanded position is obtained by correcting the reference velocity by means of a feedrate override value using an override table. Accordingly, an instruction of a single block suffices as an instruction for a single injection operation, thus simplifying CNC data processing.

Abstract: A machining end detecting device detects whether each hole or the like has completely been drilled to its bottom or not, and the latest drilling information is stored in a nonvolatile memory. In the nonvolatile memory are also stored modal data sequence numbers assigned to drilling start position determining blocks and the latest information on a drilling restart position. Upon inputting a drilling restart command from key input means such as a cycle start button, a restart block indexing device indexes, from a numerical control machining program, a restart block necessary for resuming drilling of an unfinished hole or the like on the basis of the sequence numbers and the machining end detection information stored in the nonvolatile memory. A restart positioning device positions a drilling machine at the drilling start position stored in the nonvolatile memory, and a control device causes the drilling machine to restart with the indexed restart block from the specified position.

Abstract: A dwell control system of an injection molding machine is adapted to drive an injection shaft by an electric motor (20) and to control the electric motor (20) by a numerical control unit (30). At the time of a dwell operation, the numerical control unit (30) operates the electric motor (20) under the application of a torque limit to apply a predetermined pressure to a molten material in a mold (4).

Abstract: A rotation control system for a screw of an injection molding machine is so arranged that an injection shaft 2" and a screw (2) are driven by electric motors (20) and (22). An output signal from an injection shaft position sensor (21), which provides information indicative of rotation of the electric motor (22) driving the injection shaft 2", is applied to an error register (35-1). The position of the injection shaft is sensed by monitoring the error register (35-1), and the rotational speed of the screw (2) corresponding to the position of the injection shaft 2" is obtained by utilizing an override function.

Abstract: A numerical control method for a numerical control system having a numerical control unit (NC) for numerically controlling a machine tool or the like, as well as a programmable controller unit (PC), wherein when machining is suspended and then resumed, the NC unit (1) runs the machining program from the beginning of the machining program up to a prescribed block at which machining is to be resumed, without peforming a distribution operation. During running of the program, data regarding M-, S- and T-functions in the machining program are successively delivered to and stored in the PC unit (2). At this time the PC unit (2) does not send these data to the machine side. Machining is resumed at the conclusion of a search operation up to the prescribed block.