Rockwell Automation 1785-Lxxx Enhanced and Ethernet PLC-5 Programmable Controllers - Manual (Page 255)

Publication 1785-UM012D-EN-P - July 2005
Using Main Control Programs 16-3
Configuring MCPs You configure MCPs on the controller configuration screen in your
programming software.
If the MCP is a The Following Occurs:
Ladder-logic program 1.All rungs are executed—from the first rung to the last, with all
timers, counters, jumps, and subroutines active.
2.After the END instruction in the ladder program, the controller
initiates an I/O update—reading local inputs, writing local
outputs, reading remote buffers, and writing remote outputs to
the buffer.
3.The controller starts the next MCP.
Structured-text program 1.Code is executed normally.
2.After the last instruction in the program, the controller initiates
an I/O update.
3.The controller starts the next MCP.
SFC 1.Only the active steps are scanned, and transitions from those
active steps are examined.
2.After one complete pass through the active steps, the
controller initiates an I/O update.
3.The controller starts the next MCP.