Reset Dominant (RESD)
This information applies to the
Compact GuardLogix
5370, ControlLogix
5570, Compact GuardLogix
5370, GuardLogix
5570, Compact GuardLogix
5380, Compact GuardLogix
5480, and ControlLogix
5580 controllers.The RESD instruction uses Set and Reset inputs to control latched outputs. The Reset input has precedence over the Set input.
Available Languages
Ladder Diagram
This instruction is not available for ladder diagram.
Function Block
Structured Text
RESD(RESD_tag);
Operands
Function Block
Operand | Type | Format | Description |
RESD tag | DOMINANT_RESET | structure | RESD structure |
DOMINANT_RESET Structure
Input Parameter | Data Type | Description |
EnableIn | BOOL | Enable input. If cleared, the instruction does not execute and outputs are not updated.
Default is set. |
Set | BOOL | Set input to the instruction.
Default is cleared. |
Reset | BOOL | Reset input to the instruction.
Default is cleared. |
Output Parameter | Data Type | Description |
EnableOut | BOOL | Indicates if instruction is enabled. |
Out | BOOL | The output of the instruction. |
OutNot | BOOL | The inverted output of the instruction. |
Structured text
See
Structured Text Syntax
for more information on the syntax of expressions within structured text.Description
The Reset Dominant instruction uses the Set and Reset input parameters to control latched output parameters Out and OutNot. The Reset input has precedence over the Set input.
Out will be latched true whenever the Set input parameter is set true. Setting the Reset parameter to true will override the current state of Out, setting Out to false.
When Reset returns to false, Out will be latched to the current state of the Set input parameter. OutNot will be set to the opposite state of Out.
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See
Common Attributes
for fault related attributes.Execution
Function Block
Condition/State | Action Taken |
Prescan | EnableIn and EnableOut bits are cleared to false. |
Tag.EnableIn is false | EnableIn and EnableOut bits are cleared to false. |
Tag.EnableIn is true | EnableIn and EnableOut bits are set to true. The instruction executes. |
Instruction first run | Out bit is set to false. OutNot is set to true. |
Instruction first scan | N/A |
Postscan | EnableIn and EnableOut bits are cleared to false. |
Structured Text
Condition/State | Action Taken |
Prescan | See Prescan in the Function Block table. |
Normal Execution | See Tag.EnableIn is true in the Function Block table. |
Postscan | See Postscan in the Function Block table. |
Example
When Set is true and Reset is false, Out is set true. When Reset is true, Out is cleared. The Reset input has precedence over the Set input. The RESD instruction sets OutNot to the opposite state of Out.
Function Block
Structured Text
RESD_01.Set := set_input;
RESD_01.Reset := reset_input;
RESD(RESD_01);
out_output := RESD_01.Out;
outNot_output := RESD_01.OutNot;
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