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 drum-type sequencer operable in a ladder logic program and capable of being selectively stepped in various modes; that is, in forward stepped sequence, non-sequentially, and backwardly.
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 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.