Rockwell Automation GMLC Reference Manual - Manual (Page 367)

Publication GMLC-5.2 - November 1999
330 Program Control Blocks
Restart Type
When the program is restarted using the Restart selection, multitasking is
turned
OFF , all loop counters are set to zero, and the subroutine call stack
is reset. This ensures that the diagram restarts with all critical program
control registers in a known state. The program then restarts from a
Restart Program block, with When Restart type selected (if the diagram
contains one) or from the block (if there is no Restart Program
block with When Restart type selected).
This block, with Restart type selected, has no output node. There is no
direct output from this block because program flow branches directly
either to the start block, or to a Restart Program block with When Restart
selected, at execution of this block. In many cases, the lack of an output
node on this block means that there is no connection to the block
in the diagram. This missing connection generates a warning when the
diagram is translated. In most cases this warning can be ignored .
Although the GML Commander diagram may contain any number of
Restart Program blocks with Restart selected (in order to restart the
program from many different places), the diagram can contain only one
Restart Program block with When Restart selected.
When Restart Type
The Restart Program block, with When Restart selected, provides a
marker in the diagram to allow the program to be restarted from a location
other than the start block. If you include this type of block in your GML
Commander diagram, program flow branches to it, rather than to
the block, upon execution of a Restart Program block with
Restart selected. This is useful, if certain conditions must be set up
(resetting parameter or variable values, setting discrete outputs, stopping
motion in progress, etc.) prior to restarting the program.
!
ATTENTION: Do not use more than one Restart
Program block with When Restart selected in a GML
Commander diagram.