Hi, wouldn't it been required to change SUBROUTINE CHNG_OUTPUT (IN Label :S) Label :=3D TRUE; {set the Boolean output to TRUE} ENDSUBROUTINE into SUBROUTINE CHNG_OUTPUT (INOUT Label :S) {use INOUT instead of only IN} Label :=3D TRUE; {set the Boolean output to TRUE} ENDSUBROUTINE ??? to write the value of label back to your user label variable. Regards, Andreas _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave