Rockwell Automation GMLC Reference Manual - Manual (Page 437)

Publication GMLC-5.2 - November 1999
400 SLC Blocks
The 1394 GMC Turbo can issue a request for service command and
generate an interrupt to the SLC processor. You can design an SLC ladder
program to execute on receipt of the interrupt. Refer to the APS Reference
manual for more information on SLC interrupts.
The Interrupt SLC block resides on the SLC Palette. It requires no
parameters, and has no dialog box. Because this block requires no
parameters, it always has a check mark by the upper left corner of the
block, indicating that it is complete.