摘要:
The present invention is directed to a programmable logical controller (PLC) system incorporating a universal input controller card, a universal output controller card, and a symmetrical current mirror fuse blown detector circuit. The universal input controller card is capable of tracking input voltages from 12 to 240 volts, AC or DC. The universal output controller card is capable of outputting output voltages ranging from 12 to 120 volts, AC or DC with no significant leakage current and no load resistors. The current mirror fuse blown detector circuit detects blown fuses in each output channel of the output controller card.
摘要:
A communication network for programmable logic controllers (PLCs) wherein selected memory means of each PLC have at least two ports directly accessible by other PLCs and certain registers of the PLCs are identical to enable efficient, high-speed transfer of blocks of data between the PLCs.
摘要:
An intelligent compiler particularly useful for evaluating Boolean expressions such as those associated with ladder structures. True/false paths are defined through the expressions. In a first pass for the code generation, the start code for examining each element is set out. In a second pass the relative offsets for branching from one element to the next element along both the true and false paths are filled in. In practice, execution time for evaluating ladder structures is reduced by an order of magnitude over prior techniques which use source code and an interpreter.
摘要:
A programmable logic controller system having the capability of controlling up to 64 clusters of peripheral controllers, wherein each cluster has up to seven racks of peripheral controllers, each rack having up to 16 individual peripheral controllers. Excepting for the cluster containing the programmable logic controller, each cluster is coupled to the programmable logic controller through an ethernet cable to a cluster controller. Each of the seven racks of peripheral controller cards is connected to its respective programmable logic controller or cluster controller directly (for the first rack) or through a local rack adaptor (for the other six racks). The programmable logic controller generates data, address and control signals which are used by the peripheral controllers to operate machines and equipment on an assembly line. The data, address and control signals are generated by a ladder diagram created and modified in a separate personal computer, which may be coupled to the programmable logic controller through an ethernet cable. The code representing the ladder diagram created in the personal computer is downloaded through the ethernet cable to the programmable logic controller. The ladder diagram is created and edited using a ladder editor program having the following features: scrolling, zoom in/out, free format line drawing, real time incremental compiler/linker, dynamic reconfiguration.
摘要:
A communication network for programmable logic controllers (PLCs) wherein selected memory means of each PLC have at least two ports directly accessible by other PLCs and certain registers of the PLCs are identical to enable efficient, high-speed transfer of blocks of data between the PLCs.
摘要:
A network adapter configured to functionally connect a local area network cable to a personal computer bus via the computer's standard parallel port. The adapter includes a substantially fully enclosed housing having first and second external connectors respectively configured to mate with a computer's parallel port connector and with a network cable. The adapter is primarily comprised of (1) network interface circuitry for transmitting data packets to and receiving data packets from a local area network and (2) input/output circuitry for bidirectionally transferring data bytes between the network interface circuitry and a computer's parallel port.
摘要:
A communication network for programmable logic controllers (PLC) wherein selected memory means of each PLC has at least two ports directly accessible by other PLC and certain registers of the PLC are identical. Each PLC further has an interblock gap timer to signal the PLC when its transmit time slice is to occur. The time slice consists of a block transmit time and an interblock gap time. The total update time has been optimized to engable efficient, high-speed transfer of blocks of data between the PLCs.