10 FBD programming i Training PLC Allen Bradley

Right Click on main program and choose New Routine 2.. Write New Routine name and choose Function Block Diagram for its type 3.. Right Click on Program Tags and choose New Tag 2.. FUNC

DAY 3

SESSION 2

FUNCTION BLOCK DIAGRAM (FBD)

PROGRAMMING I

ADD PFD ROUTINE

1 Right Click on main

program and choose New

Routine

2 Write New Routine name and choose

Function Block Diagram

for its type

3 Open the new routine

CREATE TAGS

1 Right Click on Program

Tags and choose New

Tag

2 Write a name, select

data type, scope, and

style for the tag

ADD A SHEET IN ROUTINE

1 Click the icon

2 Type a sheet description

FUNCTION BLOCK DATA FLOWS

FUNCTION BLOCK ELEMENT

LATCHING DATA

=

The Input Reference value does not change until the next scan execution of the routine

FUNCTION BLOCK INSTRUCTION

ADD INSTRUCTION TO SHEET

3 Drop

1 Select

2 Drag

0 DN 0

CONNECT ELEMENT(1)

1 Click button to show the block properties

2 Check to show the pin, and Uncheck to hide the pin

EXAMPLE OF SHOWING A PIN

InRawMax InRawMin InEUMax InEUMin Limiting

Out

0.0 MaxAlarm

0 MinAlarm

0

I for Input

O for Output

Check the Vis Pin

Check the Vis Pin

0 DN 0

CONNECT ELEMENT(1)

1 Click button to show the block properties

2 Check to show the pin, and Uncheck to hide the pin

CONNECT ELEMENT(2)

2 Wire Element Together

A B

• Click Output pin of the First element (A)

• Then Click input pin of the other element (B)

• Green Dots show a valid connection point

Green Dots

0 DN 0

ACC

0 DN 0

Resolve a loop

If a group of blocks are in a loop, the controller cannot determine which block to execute first In other words, it cannot resolve the loop.

LOOP ERROR

ASSUME DATA AVAILABLE

To define a wire as an input, right-click the wire and choose

Assume Data Available.

T ONR_03

T ONR

T imer On Delay with Reset

T imerEnable PRE

Reset

ACC 0 DN 0

Reset

ACC 0 DN 0

This input pin uses the output that block 2 produced on the

previous scan.

2 Program Tag Window

Shown

3 Right Click on the tag,

choose Toggle bit

0 LAlarm

0 LLAlarm

0 ROCPosAlarm

0 ROCNegAlarm

0

Window

FUNCTION BLOCK

INSTRUCTION

A IO REFERENCE & IO WIRING

HHLimit HLimit LLimit LLLimit Deadband

HHAlarm

0 HAlarm

0 LAlarm 0LLAlarm

0 ROCPosAlarm

0 ROCNegAlarm

InRawMax InRawMin InEUMax InEUMin Limiting

Out

0.0

B PROCESS INSTRUCTION (2)

2 SCL

Device Tagname (Raw

Data) Device Tagname

(Scale Data)

If set, Output is limited to between InEUMin and InEUMax.

In2 SelectorIn

Out

0.0

If SelectorIn is set Output = In2

If SelectorIn is clear Output = In1

Input1 Input2 Selector

D BIT INSTRUCTION

1 OSRI (One Shot Rise with Input)

2 OSFI (One Shot Falling with Input)

ACC 0DN

0

HORN PULSE1_ALARM 0

CDEnable PRE Reset

ACC

F COMPARE INSTRUCTION

4 GRT (Greater Than or Equal to)

PT001 0PT002

0.0

RESULT_INT SOURCE_1

0

SOURCE_2

0

H MOVE/LOGICAL INSTRUCTION

(1)

1 BAND (Boolean And)

Out = In1 AND In2 AND In3 AND In4

In2 In3 In4

Out

0

H MOVE/LOGICAL INSTRUCTION

(2)

2 BOR (Boolean Or)

3 BNOT (Boolean Not)

Out = In1 Or In2 Or In3 Or In4 Or In5 Or In6 Or

H MOVE/LOGICAL INSTRUCTION

(4)

5 DFF(D Flip Flop)

When Clock goes from cleared to set, the DFF instruction sets

Q = D When Clear is set, Q is cleared

Clear Clock

Q 0 QNot

0

Clock Clear D

H MOVE/LOGICAL INSTRUCTION

(5)

6 SETD (Set Dominant)

When Set is set, Out is set When Reset is set and Set is cleared, Out is cleared Set has precedence over Reset

BOOLEAN_1 0BOOLEAN_2

0

SET D_01

SETD

Set Dominant Set

Reset

Out

0 OutNot

0

RESULT_BOOL

Set Reset Out

SESSION 3

FUNCTION BLOCK DIAGRAM (FBD)

PROGRAMMING II