What is SET NL and why is it required

OR

PRIMARY LOAD CASE CAN ONLY BE ADDED IF SET NL COMMAND IS USED

OR

" **ERROR- Number of Primary Cases exceeds value entered in SET NL Command …"

SET NL command is required, in a file with multiple analysis commands, to let the software know how many primary load cases it would need to process so that the software can allocate the right amount of memory for the analysis and for storing the input/output data. A typical example of a file with multiple analysis commands is shown below

Load case 1
…
Load case 2
…
Load case 100
…
PERFORM ANALYSIS
CHANGE
Load case 200
…
Load case 201
…
Load case 300
…
PERFORM ANALYSIS
CHANGE

If such a file has 300 primary load cases ( REPEAT LOADs are counted as PRIMARY loads too ) you would add the SET NL command as show next

STAAD SPACE
START JOB INFORMATION
…
END JOB INFORMATION
SET NL 325
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
…

The number of primary load cases mentioned after the SET NL should be equal or little more than the actual, in case more load cases need to be added later. In the above example the number has been defined as 325 although the actual number of primary cases is 300. The value should not be too high ( say NL specified as1000 for only 300 primary load cases ) as in that case the software would reserve unnecessary amount of memory.
 
This command should be provided before any joint, member or load specifications.