Rockwell Automation DEVICENET 1771-SDN, User Manual

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Publication 1771-6.5.132 - June 2000
1-8 Before You Begin
What 1771-SDN Module
Data Tables Are and What
They Do
To manage the flow of data between your processor and the network
devices, the 1771-SDN module uses the following data tables.
•
1771-SDN Module Configuration Table
•
Scanlist Table
•
Device Input Data Table
•
Device Output Data Table
•
Device Idle Table
•
Device Failure Table
You can configure two of these data tables through RSNetWorx
software. These two tables are stored in the 1771-SDN module’s
non-volatile memory and used to construct all other data tables:
•
Scanner Configuration Table (SCT)
•
Scanlist Table (SLT)
The Scanner Configuration Table (SCT)
The SCT controls basic information your 1771-SDN module needs to
function on your DeviceNet network. It tells your 1771-SDN module:
•
if it can transmit and receive input and output data
•
how long it waits after each scan before it scans the devices
again
•
when to send out its poll messages
The Scanlist Table (SLT)
The SLT supports I/O updating for each of your devices on the
network. It also makes it possible for your 1771-SDN module to make
device data available to your processor. The SLT tells your 1771-SDN
module:
•
which device node addresses to scan
•
how to scan each device (strobe, poll, change of state, cyclic or
any valid combination)
•
how often to scan your devices