摘要:
A multiplex transmission system according to this invention includes a plurality of multiplex nodes connected to one another via a common multiplex bus, for effecting data transfer between the nodes. When reception nodes correctly receive data transmitted from one of the nodes for each frame, each of the reception nodes returns an ACK signal to the multiplex bus, registers all of the nodes connected to the multiplex bus into the ACK table in response to the ACK signal, and effects the ACK management. In this case, for example, if a door FR multiplex node causes an interruption to transmit a frame while an air-conditioning unit multiplex node is retransmitting a frame, the air-conditioning unit multiplex node effects the ACK management without regarding the ACK signal for the interruption frame as an object of the updating logic of its own ACK table.
摘要:
A multiplex transmission apparatus, having a communication control circuit for carrying out transmit-receive control of a frame of data transmitted through a bus, and an output port for outputting data in frame received by the communication control circuit. The multiplex transmission apparatus is operated by a power supply voltage supplied from a power supply circuit to perform data communication with another multiplex transmission apparatus via a bus. First and second low voltage detection circuits, when detecting preset voltage values V.sub.L and V.sub.R of a power supply voltage, reset the communication control circuit and the output port. This multiplex transmission apparatus keeps the output of the output port in a normal condition despite relatively small variations in the power supply voltage (i,e., where V.sub.L .gtoreq.power supply voltage>V.sub.R).
摘要:
When a message is transmitted, frame by frame, from any one (10) of a plurality of multiplex nodes to a common multiplex bus (MB) to which the multiplex nodes are connected, each of the multiplex nodes (20 and 30) determines that transmission of a frame therefrom is allowed when it detects a transmission permission signal (b, b') added to the frame after detection of and idle state of the multiplex bus, and starts transmitting a message data frame. This makes it possible to properly implement priority-based control according to the priority levels of the data frames irrespectively of variations in the reference clocks of the multiplex nodes. Further, receiving multiplex nodes perform frame synchronization at the rise of a special code (a) of a start code (SOM) of a message data frame, and then perform re-synchronization at the rise of a special bit pattern (b") which includes a passive bit and a dominant bit. This prevents synchronization from being deviated and bit errors resulting from deviated synchronization, thus leading to higher reliability of multiplex transmission.
摘要:
A multiplex transmission system of this invention includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. A frame of data is transmitted among the multiplex nodes through the multiplex transmission line. When a data frame transmitted from an air conditioner switch multiplex node (subnode) is received, an air conditioner unit multiplex node (main node), which is predetermined as a destination node, detects the contents of each data from an ID-a of the received data, performs a calculation on SOM to DATA 4 received, generates collation data (CRC) in accordance with the result of the calculation and transmits same. The subnode generates collation data (CRC), which is an error check code, through a calculation on the transmitted SOM to DATA 4, and compares the thus-generated CRC with the CRC received from the main node, to determine whether or not the data transmission was properly carried out. When the data transmission was carried out properly, the subnode returns a signal ACK3, and when the data transmission failed, the data frame is retransmitted, whereby the subnode need not have an ACK management function.
摘要:
A multiplex transmission system of this invention includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. A plurality of groups of different combinations of the multiplex nodes are predetermined, and a frame of data is transmitted among the multiplex nodes through the multiplex transmission line. The data frame includes a group specifying area specifying a group of nodes from which an acknowledge signal is to be returned. When a data frame transmitted from a sending node is received, each multiplex node determines whether or not it belongs to the group specified by bits in the group specifying area of the transmitted frame. When the data frame is properly received, only those multiplex nodes which belong to the specified group return the acknowledge signals to an acknowledge signal area in the data frame in accordance with the bits in the group specifying area, whereby the transmission efficiency is improved.
摘要:
A receipt acknowledgement method which is applied to a multiplex transmission system provided with a plurality of multiple nodes (11 to 17) connected to one another through a multiplex bus (18), and is capable of conducting efficient data transmission, and in which a transmitting multiplex node (13) sends out a frame and, after entry into an ACK signal area of the frame, sends out a delimiter sign consisting of passive and active two bits with a four-bit interval, thereby dividing the acknowledgement signal area. The receiving multiplex nodes (11, 12, 14 to 17) are synchronized according to an active bit sent out from the transmitting multiplex node (13), and returns ACK signals to the ACK signal area in the predetermined order when data transfer on the transmission request frame has been normally performed, whereby data transmission can be conducted at high speed with improved efficiency.
摘要:
The data storing system according to the present invention is used for a communication control circuit. The communication control circuit is equipped with a communication sequencer, which takes in a message to be transmitted to a multiplex bus, an ID table which registers data IDs of messages necessary for the station, and the first and second memory circuits which have memory areas keyed to the data IDs. When the communication sequencer takes in a message, it determines whether its data ID exists in the ID table. If the data ID exists and the frequency of occurrence is high, then data following the data ID is temporarily stored in a memory area keyed to a data ID of the first memory circuit. If the data ID exists and the frequency of occurrence is low, then the data following the data ID is temporarily stored in a memory area of the second memory circuit. When a CPU reads the aforementioned stored data, it sets the status area of the storage area, in which the data was stored, for a state that enables a data storage change.
摘要:
A multiplex transmission apparatus includes a communication control circuit connected to a bus for successively receiving data from the bus, and the received data is output from an output port to a load via an output circuit. The successively received data is once stored in a receiving buffer and is then transferred to the output port. A port control circuit, which is connected to the output port, monitors the data transferred to the output port. When at least part of the data does not change in a predetermined manner in response to the data received immediately before, the port control circuit controls data outputted from the output port so that loads controlled according to the data from the output port are held in a safe state.
摘要:
A plurality of gateway nodes for connecting high- and low-speed networks as multiplex transmission lines include buffers for signal transmission and reception, communication ICs, and control units. A priority order in signal processing is set for these gateway nodes. Only a gateway node which operates normally and has the highest priority executes signal transmission between the high- and low-speed networks.
摘要:
Communication nodes which respectively transmit periodic information and non-periodic information in multiplex fashion are provided separately. These communication nodes selectively transmit periodic information to a multiplex transmission line which is originally for transmitting the non-periodic information or non-periodic information to a multiplex transmission line which is originally for transmitting the periodic information in accordance with the state of transmission/reception of the periodic information and non-periodic information.