Abstract: An address associated with a failure in a programmable controller is provided, for reading out an operating state of each element of a sequence circuit. The address and a logic level thereof are stored in an address setting table (TA). The logic level is compared with a logic level of an actual signal stored in a signal update storage table (TB), and a difference therebetween is detected by a signal update detecting means (2). Every time a difference is detected, a signal update writing means (3) writes the address and the logic level of the actual signal into the signal update storage table (TB). The storage contents of the signal update storage table (TB) are displayed on a display means, thereby allowing an operator to check for the cause of the failure.

Abstract: A programmable controller having a memory for storing a sequence program in which messages are programmed with a processor for performing sequence control by successively executing the sequence program stored in the memory, and a display unit for displaying a ladder diagram corresponding to the sequence program of the memory as well as messages. The processor executes the sequence program and, when an alarm is sensed, causes the display unit to display a portion of a ladder associated with the alarm in accordance with alarm message data contained in the sequence program, thereby executing a rapid retrieval operation without relying upon the operator.

Abstract: A control device for indexing a stepping rotatable member, such as a turret of an NC lathe, comprising a means for generating code signals which generates different code signals at every stop position of the stepping rotatable member (TR), a means for generating strobe signals which generates the strobe signals used for reading said code signals at every stop position of the stepping rotatable member, a first comparator circuit which compares an indexing command value and the code signal, a counter which is preset by the code signal and which counts the strobe signal, and a second comparator circuit which compares a count value of the counter and the code signal value, the control device for indexing a stepping rotatable member outputs an end of indexing signal when both the comparator circuits detect coincidences.

Abstract: A programmable sequence controller which enables display of the contents of a storage means for storing input and output data to and from a machine, and which permits numerical values to be set in the storage device from an external unit. The programmable sequence controller utilizes a sending and receiving unit for an exchange of commands and other data with a numerical control device in order to transfer display content and numerical values which have been set. This allows the contents to be displayed on display means provided in the numerical control device, and permits the setting of numerical values which are entered from a data setting means provided in the numerical control device.

Abstract: A programmable sequence controller which need not be equipped with a tape reader for reading a paper tape bearing a punched sequence program or the like. A prepared sequence program or the like is punched in a paper tape in accordance with the standards of a paper tape reader which is provided in a numerical control device, and then is transferred from the numerical control device to a random access memory in the programmable sequence controller. The sequence program is read from the random access memory to permit the execution of sequential operations by processing the program.

Abstract: A method of preparing and executing a sequence program for effecting the sequence control of a sequence controller for a machine tool by executing a subroutine program. A sequence diagram is prepared, which diagram expresses a function command for a subroutine as data divided into control conditions and parameters. From the sequence diagram a sequence program is prepared, which program includes a command for reading data indicative of a control condition, and parameter data of which a subroutine is informed. The sequence program so prepared is then executed.

Abstract: A numerically controlled machine tool is equipped with a programmable sequence controller having a first storage area capable of storing operation commands, and a second storage area capable of storing a duplicate of the data planted in the first storage area without erasing the planted data. An operation command, when sent from a numerical control device to the machine tool, is stored in the first storage area and then, when the machine tool has completed the instructed operation, is read out from the first storage area and stored in the second storage area, this operation being repeated as each new command is issued. When electric power is connected to the machine tool, the data stored in the first and second storage areas is compared, an alarm being generated when the two sets of data do not agree.