Rockwell Automation 284A ArmorStart with ArmorPoint Backplane - Getting Started - Manual (Page 24)

24
Publication 284A-QS001C-EN-P - July 2006
modified. The parameter numbers all start with 1 and are numbered
sequentially to the last parameter number. The user manual is important
because it will thoroughly describe each parameter, for example, whether or
not a parameter is writable and what the parameter limits/interpretation are.
Once the device and parameter number is obtained, the next step is to
modify the configuration data for that parameter. The following screen
capture shows the data array and particularly, the parameter 8 for Device 0.
Figure 21 Data Array
The value to be modified is the .data element of the structure. For reference,
the Min_value, Max_value, and Name_String for the parameter is also in
the structure, so that the user knows what the minimum and maximum
allowable values are for the data. It is important to realize that the data is in
a raw format. In other words, this data could be considered a Boolean, a bit
mask, an ASCII string, an integer, a byte, etc., depending on the definition
of the parameter in the ArmorStart. Also, there could be an implied decimal
point, scaling, and different units involved. It is important that the user
fully understand and verify the raw data value being modified with the
user manual, so that it is correctly interpreted by the ArmorStart or
undesired operation in the ArmorStart may occur.
Once the data is written, during a System Wide Write function, the ladder
logic will read it back and put into the .Last_Read_Value of the structure.
This will be a handy visual verification that the data was written correctly.