Abstract: In a communication control apparatus in which the master station transmits a batch transmission frame to a plurality of slave stations and individual response frames are transmitted from the respective slave stations to the master station, the master station previously transmits the batch transmission frame containing the transmission order designation of the slave stations. When each of these slave stations responds to the slave station, the slave stations successively and continuously transmit the response frames to the master station based upon the transmission order designation transmitted from the master station every time the response frame transmission by the slave station prior to the own slave station is accomplished.

Abstract: There is disclosed a bus control device which reduces the data traffic amount of a parallel bus to enhance the performance of the bus control device. A local CPU (111) controls a serial bus transmission/reception controller (113) to give a transmission timing to a transmission interface (120). The bus transmission/reception controller (113) transmits to a serial bus a transmission frame formed by reading predetermined transmission data from a memory (112) storing addresses of a plurality of units (4) connected to the serial bus (51) and transmission/reception data to be transferred to the plurality of units. As a result, transmission/reception is performed with units connected to the serial bus (51) out of the plurality of units via the serial bus, the destination address and transmission data are read from the memory during transmission, and reception data is written to the memory during reception.

Abstract: A basic system of an NC unit and a distributed type remote I/O unit executes time division signal transaction through a half-duplex serial communication line, and in case where the distributed type remote I/O can not detect a receiving start state of a transmission frame from the basic system of the NC unit for a specified period of time, output is reset, and the basic system of the NC unit checks a type of and data setting in the distributed type remote I/O unit, and also checks a result for an input/output test and the current situation of communication according to a header pattern of a transmission frame.

Abstract: In a system that connects a numerical controller (NC) unit to an operation board and to a plurality of remote I/Os with serial communication lines, the control method of the serial communication line between the NC unit and the operation board is similar to the control method of the serial communication line between the NC unit and the remote I/Os, so that the operation board can at times use the same communication lines as the remote I/Os to improve the flexibility of the system. The frame length and communication interval of data transmitted/received between the NC unit and the operation board are the same as those of data transmitted/received between the NC unit and the remote I/O. The operation board and the remote I/O can thus be connected to a common communication controlling portion of the NC unit.

Abstract: A basic system of an NC unit and a distributed type remote I/O unit executes time division signal transaction through a half-duplex serial communication line, and in case where the distributed type remote I/O can not detect a receiving start state of a transmission frame from the basic system of the NC unit for a specified period of time, output is reset, and the basic system of the NC unit checks a type of and data setting in the distributed type remote I/O unit, and also checks a result for an input/output test and the current situation of communication according to a header pattern of a transmission frame.

Abstract: A communication control apparatus comprises a transmission control section for successively reading out words forming the transmission frame every once from a transmitting RAM in the case of transmission, a receiving control unit for writing the words forming the receiving frame every once in the case of receipt to a receiving RAM, an automatic transmitting timing setting section for repeating the above-described operation correspondingly to the number of frames every unit time in the case of transmission and receipt, and a plurality of transmission and receipt address base registers and transmission and receipt data base registers for storing therein a top address and a word length of the transmitting RAM and the receiving RAM every each transmitting and receiving frame.