Rockwell Automation 1787-GEN2SKIT, -2, -3, -4, -5, -6, -7 DeviceNet Starter Kit User Manual - Manual (Page 98)

Publication DNET-UM003A-EN-P - August 2000
4-2 Build the Scanlist
What is a Scanlist? Before a scanner can successfully communicate to the devices on a
DeviceNet network, it must first be configured. There are module
level parameters and also the scanlist. The scanlist contains all of the
information to tell the scanner how to communicate to the devices.
The scanner uses the information contained in the scanlist table (SLT)
to determine:
•
what devices to scan
•
how often to scan each device
•
what memory locations in the device contain the desired input
or output data; and, the size of the data
•
the number of bytes to send or transmit (Tx size)
•
the number of bytes to receive (Rx size)
•
how to communicate with each device (strobed, polled, change
of state, cyclic, or any valid combination of these I/O
parameters)
•
where to map input data and output data so that the processor
can read and write it
•
how to communicate with the processor (DIO, BTR/BTW, or
M1/M0 data transfer)
You can automatically configure most of the data by using the
automapping feature of RSNetWorx. This manual describes both
manual and automatic mapping procedures.