Series 90-70 Genius Bus Controller Manual, GFK-2017

1Input Data from Devices on the BusThe Bus Controller receives input data from each input block, I/O block, and remotedrop each time the block or Remote I/O Scanner has the communications token.(Because this data is broadcast, it may be received by any other bus interface moduleoperating on the bus).BusControllerInputs from Block 41 2 3 4TokenThe Bus Controller stores all the input data it receives. Once per CPU sweep, the CPUreads all discrete and analog inputs from the Bus Controller. (Analog data is notmultiplexed).Output Data from the CPUAs the application program executes, the CPU sends outputs and any commands tothe Bus Controller. The Bus Controller stores this data, transmitting it on the bus eachtime it has the communications token. Unlike inputs, which are broadcast, outputs aredirected to the specific device that should receive them.PLC CPUReads Stored InputsStores New OutputsBusControllerOUTPUTSTokenBusControllerhas token1 2 3 4Outputs for 4 Input/2 Output Analog BlocksFour words of %AQ memory are assigned to a 4 Input/2 Output block by theconfiguration software. The CPU stores the output data as shown below. Locations“n+2” and “n+3” are not used by the block.n+3 n+2 n+1 n %AQnot used not used channel 2 channel 1GFK-2017 Chapter 1 Introduction 1-7