1771-6.5.132, PLC-5 DeviceNet Scanner User Manual

Data Map Example D-7Output Data Table FormatsThe following illustrates an output data mapping scheme example fora scanner in 2-slot addressing mode.Note: 1 word = 2 bytes1 byte = 8 bits16N1bit numbernode numberN1 = node #1Bit numbering in the data table isright to left, beginning with zero.15 0Module Statusword 0In 2-slot addressing mode, the output bitsfor channel A and channel B devices arewritten to the scanner’s output data table.The bits are stored in ascending numericorder, according to node address. Themapping begins with channel A devices atbit 16 of the table.There are 64 possible node addresses pernetwork. Channel A devices fill the firstfour words (after the module status word).Channel B devices fill the last four wordsof the table.Channel AChannel B31799539N2316N180N1word 1word 2word 3word 4word 5word 6125N45word 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 node63; 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