Rockwell Automation 283A ArmorStart with ArmorPoint Backplane - Getting Started - Manual (Page 15)

Publication 283A-QS001C-EN-P - July 2006
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is a flag word that tells the ladder logic if the parameter is read only. If the
read only bit is set, then the ladder logic will skip the additional attribute
reads and will go to the next parameter. If the parameter is writable, then the
logic will read the size, min. allowed value, max. allowed value, the
parameter name, help string and the raw data of each parameter. These
attributes are stored in the data array for use later when the configuration is
written to each ArmorStart. The logic requires that a system wide read
function be completed prior to a system wide write function being
requested.
Note: A system wide read function should be done anytime that a new
ArmorStart is added to the system or an ArmorStart is updated
with a more recent version. This assures that the data array in
the logic matches the total system.
Once a system wide read is done, the raw data of the individual parameters
in the data array can be modified and a system wide write function activated
from a bit in the ladder logic. Only parameters that changed will be written
to the ArmorStart devices, and after a write is done the parameter is read
back and stored in the data array for comparison. If the write and reread
value do not match, an Error Report is generated.
If an error occurs for any reason, during a system wide read or write, an
error report will be logged, containing the device and parameter it occurred
on. Also the status and extended status of the message block is logged in
case the error originated there.
I/O Tree Overview
In order to transfer I/O information, the ArmorStart needs to be added to the
I/O tree of the Logix processor. The details of doing this are outside of the
scope of these instructions, but screen captures of the completed
configuration are included below for reference. The configuration below
shows the EtherNetIP card in the Logix chassis slot 1. The 1738-AENT
module is always located at slot zero in the subnet and the ArmorStart
device is located in slot 2 on the subnet. These slots are circled below for
you reference.
Figure 9 Logix Processor I/O Tree