Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 672)

OCI Parameters
Chapter 38
38-6
Change the size of these watchlists when your OCI application program
requires a larger watchlist size or you suspect machine performance is
suffering because the watchlist size is larger than necessary for your
application. To help you identify how large your watchlist must be for
your application use the following table in conjunction with appendix A of
your OCI API developers reference manual. Appendix A of the API
developers reference manual will help you identify the data types of items
used in your application:
This Data Type Watchlist Bytes Used:
Overhead per item 28 bytes/item
All Command Requests 0
BOOL 1
BYTE 1
SINT 1
USINT 1
INT 2
UINT 2
DINT 4
UDINT 4
LINT 8
STRNG 128
LREAL 8
DATE 8
TIMEOFDAY 8
LTIME 8
STRUCT 8
REAL 4
The overhead of 28 bytes/item applies to each data item in the watchlist.
watchlist =
(APIItems)
(i=1)
overhead
i
+ [(numarrayindices)
i
× (bytes DataType)
i
]
Any item placed on a watchlist remains on the watchlist until removed by
your application or heart beat timeout occurs (see
JBoxDestroyInactiveParts in your API reference manual).