1771-6.5.132, PLC-5 DeviceNet Scanner User Manual

D-8 Data Map ExampleThe following is an output data mapping scheme example for ascanner in 1-slot addressing mode.Note: 1 word = 2 bytes1 byte = 8 bits16N1Output Image Table23 22 21 20 19 18 17 16N1(for discrete output data bits)bit numbernode numberN1 = node #115 0Module Status39Bit numbering in the data table isright to left, beginning with zero.24N9word 0word 1In 1-slot addressing mode, eight bits of theoutput data table are used for the outputimage table. The image table is fordiscrete output bits. In the default mode,the processor writes the output bits of thefirst eight nodes to the output image tablevia DIO. The output bits from the remainingnodes are written to the output data table.Channel A79word 2word 3word 4Note that the output image table beginswith bit #16, where the output bit for node#1 (MAC ID 1) is written. The output datatable now begins with bit #40, where theoutput bit for node #25 (MAC ID 25) iswritten.Channel B95125N4580N1word 5word 6word 7143word 8The scanner takes the output bits from itsoutput data table and organizes them into astrobe message. The strobe messagecontains one bit for each node address,0-63. In default mode, the scanner is node0; therefore, this bit is empty. The scannersends a separate strobe message to eachnetwork, via channel A and channel B.Output Data Strobe Message channel AEach node’s output bit is mapped to a bit number in thestrobe message that directly corresponds to thatparticular node’s MAC ID. For example, the output bitfor node #23 is mapped to strobe bit #23.Bit numbering in the data table isright to left, beginning with zero.63 - - - - - - - - - - - - - - - - - - - - - - - - - 23 - - - - - - - - - - - - - - - 1 0N23N1Output Data Strobe Message channel B63 - - - - - - - - - - - 45 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 0N45N1Publication 1771-6.5.132 - June 2000