Introduction to ControlLogix Function Block

1
Introduction to ControlLogix Function Block
2
Function Block Programming

• Relatively new PLC language
• ControlLogix only Allen-Bradley PLC family to
  support function block
• From IEC 1131-3 specifications

3
Uses of Function Block

• Process control such as PID
• Drive systems

4
Why Function Block?

• New instructions
• Advanced function block instructions have
  instructions that would take many ladder rungs to
  create equivalent logic.
• Function block has user-defined blocks.

5

• Not all relay ladder logic instructions are
  available in function block.
• A ControlLogix routine must be 100 the same
  programming language.

6
Function Block Components

• Function block routine
• Function blocks for instructions
• Input and output references
• Wire connectors
• Dotted wire for bit data
• Solid line for value data

7
Create a New Function Block Routine
Routine name
Description if desired
Select routine type
8
Function Block Routine
Continuous Task
Main Ladder Routine
Function Block Routine
9
Function Block Sheet
Delete sheet
Navigate between sheets
Sheet number
New sheet
Sheet Name
Show / hide grid
Coordinates
Grid
10
Language Element Toolbar
Input reference
Output reference
Output wire connector
Input wire connector
11
Input Reference for Bit
Bit value
Input Reference
Dotted lines identify as bit or BOOL data
12
Input Reference for Values
Bit data
Tag value
Solid line signifies the tag contains a value
13
Output Reference
Output reference to tag
Bit value
Dotted line signifies bit data
14
Wire Connectors (1 of 3)

• Used to move function block diagram wire from one
  sheet to another
• Output from one sheet is an input to the next
  sheet

15
Wire Connectors (2 of 3)
Sheet One
Output wire connector
Sheet Two
Input wire connector
Coordinates
16
Wire Connectors (3 of 3)

• Coordinates refer ahead to the input wire
  connector on the next sheet or back to the output
  wire connector on the previous sheet.
• 2A1 refers to sheet 2 coordinates A1.
• 1C2 refers to sheet 1 coordinates C2.

17
Language Element Toolbar
Boolean AND
Boolean OR
Boolean Excusive OR
Boolean NOT
Up / Down counter
Timer on-delay with reset
18
Boolean AND
19
Relay Ladder AND Logic
20
Boolean OR
21
Relay Ladder OR Logic
22
Boolean Exclusive OR
23
Relay Ladder Logic Excusive OR
24
Boolean Not
25
Relay Ladder NOT Logic
26
Adding Address Tag
27
Drag Wire To Target
Drag wire to target. When target changes drop
wire.
28
Function Block Properties
Click here to go to properties.
29
BAND Properties Box
Parameters visible?
Monitor values
Execution order