Step 6. Defining And Mapping Cyclic Links; Cyclic Link - Control Techniques UD77 DeviceNet Startup Manual

Upload is done and the network is displayed. No UD77 / Unidrive is assigned to the
Scanner yet.

Step 6. Defining and Mapping Cyclic Links

Now that all devices connected to the network are known, the next step is to assign each
slave device to a master device. For this project, the UD77(s) are assigned as Slaves to
the Scanner. Dragging the icon for the node to the scanner performs the assignment.
The act of assigning a Slave to a Master declares an "empty" cyclic link that is later
mapped from the 1747-SDN Scanner to the particular parameters in the Unidrive.
Three cyclic links into and three cyclic links out from the 1747-SDN Scanner to
the two UD77 / Unidrive(s) have been created and mapped using the default
mapping defined in the Control Techniques generic *.EDS files for the Unidrive.
Cyclic links from each Unidrive / UD77 have been "mapped" into the SLC
address space via the "I.slot.x" direct input and "O.slot.x" direct output files, not
the scanner "M0" and "M1" files. The scanner's "M0" and "M1" files can handle
larger blocks of I/O, but require multiple PLC scans to deliver all information.
The simple default cyclic links that are described in this guide can be extended
from two Unidrive / UD77 3 word sections to a maximum of ten 3 word sections
using the I/O data tables: SLC Input image table is limited to 31 words in plus 1
word status; and
SLC Output image table is limited to 31 words out plus 1 word command.
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