Installation manual

1 Publication 1747-RM001G-EN-P - November 2008
Chapter 6
Program Flow Instructions
This chapter contains general information about the program flow instructions
and explains how they function in your application program. Each of the
instructions includes information on:
• what the instruction symbol looks like.
• how to use the instruction.
About the Program Flow
Control Instructions
Use these instructions to control the sequence in which your program is
executed.
Control instructions allow you to change the order in which the processor
scans a ladder program. Typically, these instructions are used to minimize scan
time, create a more efficient program, and troubleshoot a ladder program.
Table 6.1 Program Flow Instructions
Instruction Mnemonic Instruction Name Purpose Page
JMP and LBL Jump to Label and Label Jump forward or backward to
the specified label instruction.
6-2
JSR, SBR, and RET Jump to Subroutine, Subroutine,
and Return from Subroutine
Jump to a designated subroutine
and return.
6-3
MCR Master Control Reset Turn off all non-retentive outputs
in a section of ladder program.
6-6
TND Temporary End Mark a temporary end that halts
program execution.
6-7
SUS Suspend Identifies specific conditions for
program debugging and system
troubleshooting.
6-8
IIM Immediate Input with Mask Program an Immediate Input
with Mask.
6-8
IOM Immediate Output with Mask Program an Immediate Output
with Mask.
6-9
REF Refresh Interrupt the program scan to
execute the I/O scan and service
communications.
6-10