Rockwell Automation 284 ArmorStart User Manual - Manual (Page 272)

11-4 ArmorStart® to ArmorPoint® Connectivity
Once the appropriate device configuration is done to a User Defined
Structure in the ladder logic file, a bit will need to be turned on in the
logic to trigger a system wide read of the system. This system wide
read, goes out and reads certain attributes of every parameter of every
ArmorStart in the system and stores the information into a large data
array. The first attribute 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 11.3 Logix Processor I/O Tree