Rockwell Automation T8082 Trusted Toolset Suite - Manual (Page 79)

Trusted
TM
Toolset Suite T8082
Issue 14 Feb 10 PD-T8082 79
watchdogs on 8480 modules and the watchdog times on these modules should be adjusted. (see
TN20057).
Minimum scan time 32ms
This is set to allow room for communications traffic and background tasks. It is especially important on
some hybrid systems where legacy I/O scanning is asynchronous to main processor scanning.
Scan time estimations are given in PD-8110B. Note that these tend to be pessimistic and are only
estimates.
Maximum total variables of any type 65,535
This is described in TA20004 and a method for determining the limit is given in AN-80011. This covers
all variables of any one type (Boolean, analogue, timer etc.) across the whole application, including
internal temporary variables to reference wires and connection corners etc. (see AN-80009).
Maximum instance number 9999
Each FBD program has a numbering scheme in its source code (the application file program.lsf) for
variables, functions/function blocks and wires. The numbers are allocated sequentially from the
highest, and lower numbers are not reused. When the numbers reach 10000 the number rolls over and
the online update manager cannot recognise them; it will always apply an online update and some
function block local variables will be reset. AN-80009 describes a method to reset these numbers,
essentially by cutting and pasting the logic.
Maximum FBD program size Approximately 75% of diagram area
The maximum FBD program complexity (as measured by the size of the application file program.lsf)
and the proportion of space used by the program on the diagram, do not have clear limits. At large
sizes, a program will appear to compile properly but it is possible that not all wires on the diagram will
work. It is recommended to keep the program to less than 75% of the available diagram area, and to
turn off power flow debugging on programs larger than 50% of the area (because power flow
debugging adds many temporary variables).
Maximum application or program name 8 characters
Maximum variable name 32 characters (at TUV 3.5 toolset)
16 characters (before TUV 3.5 toolset)
Maximum conversion table points 32 per table
Maximum conversion tables 127
Maximum programs in an application 255
Maximum levels of program hierarchy 20 (depth of subprogram nesting)
Maximum FBD diagram width 200 columns (see above for height)
Maximum I/O connection boards 256
Maximum function (block) parameters 32 (total of inputs and outputs)
The ISaGRAF users’ guide lists other limits but those detailed above will be the first to be encountered.