DL205 User Manual, 4th Edition, Rev. B
5–185
Chapter 5: Standard RLL Instructions - Program Control
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A
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D
Master Line Set (MLS)
The Master Line Set instruction allows the program to control
sections of ladder logic by forming a new power rail controlled by the
main left power rail. The main left rail is always master line 0. When
a MLS K1 instruction is used, a new power rail is created at level 1.
Master Line Sets and Master Line Resets can be used to nest power
rails up to seven levels deep. Note that unlike stages in RLL
PLUS
, the logic within the master
control relays is still scanned and updated even though it will not function if the MLS is off.
Master Line Reset (MLR)
The Master Line Reset instruction marks the end of control for the
corresponding MLS instruction. The MLR reference is one less than
the corresponding MLS.
Understanding Master Control Relays
The Master Line Set (MLS) and Master Line Reset (MLR) instructions allow you to quickly
enable (or disable) sections of the RLL program. This provides program control flexibility.
The following example shows how the MLS and MLR instructions operate by creating a sub
power rail for control logic.
þ
þ
þ
þ
230
240
250-1
260
K
aaa
MLS
Operand Data Type
DL230 Range
DL240 Range
DL250-1 Range
DL260 Range
aaa
aaa
aaa
aaa
Constant K
1-7
1-7
1-7
1-7
þ
þ
þ
þ
230
240
250-1
260
K
aaa
MLR
Operand Data Type
DL230 Range
DL240 Range
DL250-1 Range
DL260 Range
aaa
aaa
aaa
aaa
Constant K
0-6
0-6
0-6
0-6
X0
X1
X2
OUT
Y7
X3
MLS
X10
K1
K2
K0
K1
MLS
OUT
MLR
MLR
OUT
Y10
Y11
Direct
SOFT
When contact X0 is ON, logic under the first MLS
will be executed.
When contact X0 and X2 are ON, logic under the
second MLS will be executed.
The MLR instructions note the end of the Master
Control area.
DS
Used
HPP Used
