Allen-Bradley SLC 500 DeviceNet, User Manual, Page: 105 / 139

Publication 1747-6.5.5 - August 2000
Data Map Example A-5
The processor writes output data for each scanned device in the scanner’s
discrete output data table. The scanner then maps each bit into a strobe
message that is sent to all scanned devices. The bit number, where a particular
device’s data is mapped, directly corresponds to that device’s MAC ID. This is
true for mapping into the scanner’s data table as well as the scanner’s strobe
message. For example, node # 11’s output bit is mapped in bit number 11 of
the scanner’s output data table. In addition, this same output bit is mapped
from bit 11 of the data table to bit number
11 in the strobe message.
In this example, nothing is mapped from the DeviceNet output
data area of the processor’s M0 file. All output data is mapped
from the processor’s output image table to the scanner’s
discrete input data table.
1747-SDN Output Strobe Message
The strobe message contains one bit for
each scanned device on the network.
1747-SDN Scanner Discrete
Output Data Table
15
31
47
63
11 0
16
32
48
word 1
word 2
word 3
word 4
15 0 word 0
word 0 Command (1 word)
words 1-31 Device Output Data (31 words)
words 0-223 DeviceNet Output Data (224 words)
words 224-255 Client Server Table (32 words)
SLC Processor M0 File
SLC Processor Output Image Table
bit number
63 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 0 11