Enable line feature – Rockwell Automation DeviceLogix System User Manual User Manual
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Publication RA-UM003B-EN-P - February 2010
Chapter 2 Navigate the Function Block Editor Interface
Latch Functions
There are two kinds of Latch functions: Set Dominant Latch (SR) and
Reset Dominant Latch (RS). Unlike the Latch in RS Logix 5000,
DeviceLogix Latch requires the Reset binding. So the Set/Reset
appears in pair and the RS type and SR type have different element
order. See its truth table below.
Enable Line Feature
Enable Line can be supported by each instruction type in the Function
Block Editor. When an instruction supports the Enable Line feature,
that particular instruction can only be executed when the Enable Line
feature is on; otherwise, that instruction maintains the data from the
last data scan. Each instruction that uses Enable Line must configure
both an input and an output; the output has the same real time data as
the input, passing the enable information to the next instruction.
Function Block
Type
Input 1
Input 2
Value at time +
t
0
Value at time +
t
0+1
SETD (Set
Dominant)
0
0
0
0
0
1
0
1
1
0
0
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
0
1
1
1
1
RS (Reset
Dominant)
0
0
0
0
0
1
0
1
1
0
0
0
1
1
0
0
0
0
1
1
0
1
1
1
1
0
1
0
1
1
1
0