Chapter 2
Produce a Large Array
40
Rockwell Automation Publication 1756-PM011J-EN-P - February 2018
In addition, the array must contain an extra 122 elements. In other words, it
must be 122 elements greater than the greatest number of elements that you
want to transfer.
•
These elements serve as a buffer.
•
Because each packet contains the same number of elements, the buffer
prevents the controller from copying beyond the boundaries of the
array.
•
Without the buffer, this would occur if the last packet contained fewer
than 123 elements of actual data.
Follow these steps to produce a large array.
1.
In the
Controller Tags
folder of the controller project that produces
the array, create these tags.
P
Tag Name
Type
array_ack
DINT[2]
X
array_packet
DINT[125]
2.
Convert array_ack to a consumed tag.
For
Specify
Controller
Name of the controller that is receiving the
packet.
Remote Tag Name
array_ack
Both controllers use the same name for this
data.
3.
In either the
Controller Tags
folder or the tags folder of the program
that will contain the logic for the transfer, create these tags.
Tag Name
Type
array
DINT[x] where x equals the number of
elements to transfer plus 122 elements
array_offset
DINT
array_size
DINT
array_transfer_time
DINT
array_transfer_time_max
DINT
array_transfer_timer
TIMER
4.
In the array_size tag, enter the number of elements of real data.
The value of x from step 3 minus the 122 elements of buffer.
5.
Create or open a routine for the logic that creates packets of data.
Produce a large
array
