Cutler-Hammer D320 PLC, User Manual

Page: 99 / 258

Chapter 6: Instructions
87
Instruction
Mnemonic Master Control Set (Reset) Range
Bit
Word
MCS
MCR Execute block circuit using the
specified conditions.
Double words
Ladder
MCS: Enable processing of the following block of instructions.
MCR: End block of instructions enabled by MCS.
Description
1. MCS (Master Control Set)—Marks the start of a conditional block of instructions. When the
input conditions to the MCS are false, the block of instructions that follow are executed as
false. Must be used with MCR.
2. MCR (Master Control Reset)—Marks the end of a conditional block of instructions. Must be
used with MCS.
3. Up to seven MCS/MCR blocks can be nested.
4. If you use eight or more MCS/MCR nested blocks, a syntax error will occur.
Example
Program Expression Time Chart
The circuit block R15.0 bit is reset (0) by R000.0.
(MCS)
circuit block
(MCR)
condition
MCS.. Loop 1
MCR
MCS.. Loop 2
MCR
MCS.. Loop 3
MCR
F0.15 R15.0
(SET)
R000.0
(MCS)
R15.0
(RST)
(MCR)
R00.0
R15.0