Indexing through an array using ST programming

[jonesy29847]

I am trying to code a string concatenization subroutine using ControlLogix ST.

The sub uses 3 Input parameters.
InputParam1 an SINT, is how many elements in the array, 3 in this case.
InputParam2 a STRING, is a pad character, : in this case
InputParam3 is the array of STRING with the following values for the elements InputParam3[0] = HH, InputParam3[1] = MM and InputParam3[2] = SS.

The calling convention for CONCAT is CONCAT(String1, String2, String3)

The subroutine is codded as follows:

index := 0

WHILE(index < InputParam1) DO
CONCAT(InputParam3[index], InputParam2, PartInfo);
index := index + 1
END_WHILE

The software didn't seem to like a RET at the end of this routine, but the processor didn't crash either.

I expect PartInfo to contain HH:MM:SS when the subroutine returns.

Any help would be appreciated.

Thanks