1. Programmable Controller Basics Files And Programs
MicroLogix Packaged Controllers 1

2. We are going to discuss... 1. What Are Program Files
2. Program File Functions
3. Ladder Logic Concepts
4. I/O Addressing
5. Logic
6. Examples

3. Memory Organization MicroLogix 1000 only DATA FILES MicroLogix 10001 2 3 4 5 6 7
Output File
Input File
Status File
Bit File
Timer File
Counter File
Control File
Integer Files
MicroLogix 1000
MEMORY
PROGRAM
FILES 1 2 3 4 5
6 - 15
System
Reserved
Main Program
Error File
HSC File
STI File
Subroutine
Files
MicroLogix 1000 only

4. Memory Organization MicroLogix 1000 only MicroLogix 1000 MEMORY
PROGRAM
FILES 1 2 3 4 5
6 - 15
System
Reserved
Main Program
Error File
HSC File
STI File
Subroutine
Files
MicroLogix 1000 only

5. File 0 - System File Dedicated & Reserved file
Used to store various system related information.
Processor type and configuration
Communication parameters
I/O configuration
Passwords
Misc...

6. File 1 - Reserved Future New enhancements New features
New functionality

7. File 2 - Main Program Dedicated & Open file Main Ladder Program
Typically is where the “main” user program resides
Must have some program logic

8. File 3 - Error File Preconfigured and Open file
Referred to as the Error Subroutine
Will be “scanned” whenever a recoverable fault is detected (Allows users to clear certain errors and inhibit a shutdown)
Recoverable faults include:
Retentive data lost (0005)
Startup protection after power loss (0016)
Minor Error at end of scan (0020)
File boundaries violated ( Sequencers 0032, Stacks and Bit Shifts (0033)
Negative data in ACC or PRE of a timer (0034)
Invalid HSC preset (0037)
May be used as a user subroutine, but is not recommended

9. File 4 - High Speed Counter File
Preconfigured and Open file
Referred to as the HSC Subroutine
Will be “scanned” whenever a HSC interrupt occurs
HSC Interrupts are:
“Preset” data value is reached (High or Low)
Underflow or Overflow conditions are detected
May be used as a user subroutine, but is not recommended

10. File 5 - Selectable Timed Interrupt File
Preconfigured and Open file
Referred to as the STI subroutine
Scanned whenever the STE instruction is set (1)
Adjustable interval, 10msec resolution
May be used as a user subroutine, but is not recommended

11. Files 6-15 - User Subroutines
“Open” Files
Typically used for application specific requirements.
Accessed from file 2 (Main program) through special program flow instructions
JSR Jump to Subroutine and return
SBR Subroutine Identifier
RET Ret to Main program
Nesting of subroutines is allowed (8 Levels allowed, 3 Levels if the Error, HSC or STI subroutines are enabled)
MicroLogix 1000 and SLC 500 only

12. Relay Ladder Logic (RLL)
What is Relay Ladder Logic?
Is the primary programming language for PLCs
A graphical representation of the program designed to look like relay logic

13. Ladder Logic Concepts | | ( ) | | |/| | | | | |/| | | |/| | | | | |/|
Read / Conditional
Instructions
Write / Control
Instructions
| |
Start (Rung #1)
( )
| |
|/|
| |
| |
|/|
| |
|/|
| |
| |
|/|
( )
End (Rung #5)

14. Ladder Logic Concepts |/| | | ( ) |/| |/| T F F T T T
Read / Conditional
Instructions
Write / Control
Instructions
|/|
| |
( ) T F F
No Logical Continuity
|/|
|/| T T T
Logical Continuity

15. Logical AND Construction
IF input 4 AND input 5 have power
THEN energize output 0 On
| |
I/4
| |
I/5
( )
O/0 T T T
Logical Continuity

16. Logical OR Construction
IF input 4 OR input 5 have power
THEN energize output 0 T On
| |
I/4
( )
O/0
Logical Continuity
| |
I/5 F F On
| |
I/4
( )
O/0
Logical Continuity
| |
I/5 T

17. Complex Construction | | |/| | | | | |/| ( ) | | | | |/| |/| | | | |

18. Read Instructions -| |- -|/|- The instruction is:
If the input device is
The input bit is
Examine ON
-| |-
XIC
Examine OFF
-|/|-
XIO
Open (0)
Logic 0
False
True
Closed (1)
Logic 1
True
False

19. Write Instruction -( )- Rung State Output Bit Output Terminal OTE
| |
|/|
( ) T
Rung
State
Output
Bit
Output
Terminal
OTE
Output Energize
-( )-
TRUE ON
ENERGIZED
FALSE
OFF
De-energized

20. Putting it Together | | ( ) I/8 O/0 PB1 Supply Voltage Unused Unused
COM
I / 0
I / 1
I / 2
I / 3
I / 4
COM
I / 5
I / 6
I / 7
I / 8
I / 9
L 1
L 2 / N
GND
VAC
O / 0
VAC
O / 1
VAC
O / 2
VAC
O / 3
VAC
O / 4
O / 5
VDC
VDC
VDC
VDC
VDC
Supply
Voltage
I/8
O/0
| |
( )

21. Addressing Example | | | | | | ( ) HHP I/5 I/6 I/7 O/0 Logix I:0/5
PB1
LS1
PS2
SOL6
I/5
I/6
I/7
O/0
| |
| |
| |
( )
HHP
I/5
I/6
I/7
O/0
Logix
I:0/5
I:0/6
I:0/7
O:0/0
ADDRESS
DEVICE
PB1
LS1
PS2
SOL6

22. Relay Logic to Ladder Logic
|/|
CR3 M1
PB1
LS1
SOL2
PB2
LS3
LS4
I/4
I/6
O/0
O/1
| |
( )
I/5
I/7
B/0
|/|
I/8
I/9
| |
Again, the similarities are virtually identical.
The primary enhancement is that if changes are needed, or if other logic or conditions need to be added, it’s as simple as a few keystrokes on the computer.
INPUT Address Assignment:
PB1- I/4 PB2- I/5
LS1- I/6 LS2- I/7
LS3- I/8 LS4- I/9
OUTPUT Address Assignment:
SOL2- O/0 M1- O/1 29