Lab Exercise 1
Simple Ladder Logic
Table of Contents
Page
Objectives
Solution Should Include
I.
Wiring the Lights and Switches
II.
Series Operation (Logical AND)
A. Getting Started with the ControlLogix
B. Getting Started with the PLC-5
C. Getting Started with the SLC-500
D. Programming the Series Circuit
III.
Parallel Operation (Logical OR)
IV.
Motor Start/Stop
V.
Timer Operation
VI.
Counter Operation
VII. Flashing Lights
VIII. One-Shot Pulse
IX.
Turn Signal
X.
Cereal Box Filler
Lab 1-1
Lab 1-1
Lab 1-1
Lab 1-6
Lab 1–7
Lab1–10
Lab1–14
Lab 1–17
Lab 1-21
Lab 1-23
Lab 1-23
Lab 1-24
Lab 1-26
Lab 1-26
Lab 1-26
Lab 1-27
Copyright ©2005, Dogwood Valley Press, LLC. Permission to copy and post these notes granted
to instructors of a course that uses Programmable Logic Controllers: An Emphasis on Design
and Application by Kelvin T. Erickson.
106753457
Lab 1 - 1
PLC Short Course
Objectives
This exercise is designed to provide working knowledge of the Allen Bradley
ControlLogix, PLC-5, or SLC-500 and the RSLogix software. The PLC is programmed for
simple logical operations using ladder logic diagrams and the appropriate software tools. Lamp
loads and switches are used to simulate input/output conditions and the ladder logic programs are
verified for correct operation.
Solution Should Include:
Listing of the ladder logic program for each part
I. Wiring the Lights and Switches
Connect the lights and switches to the I/O modules. Typical connections to the modules
are shown in Figures 1 - 6 (Note: these are not the actual connections; you need to figure that
out). Use the appropriate figures depending on the PLC (ControlLogix, PLC-5, or SLC-500). A
diagram of the switches and lights is shown in Fig. 7. Use the following connections:
Allen-Bradley
Tag/Symbol/
Variable
Group
(Slot)
Start_PB
Modicon
Channel
ControlLog ix
Address
PLC - 5/SLC - 500
Address
1
00
1:I:Data.0
I:1/00
1
1
100001
Stop_PB
1
01
1:I:Data.1
I:1/01
1
2
100002
SW3
1
02
1:I:Data.2
I:1/02
1
3
100003
SW4
1
03
1:I:Data.3
I:1/03
1
4
100004
LA1
2
00
2:O:Data.0
O:2/00
2
1
000001
LA2
2
01
2:O:Data.1
O:2/01
2
2
000002
LA3
2
02
2:O:Data.2
O:2/02
2
3
000003
LA4
2
03
2:O:Data.3
O:2/03
2
4
000004
LA5
2
04
2:O:Data.4
O:2/04
2
5
000005
Row Channel Address
Have your wiring checked by the instructor before you apply power !!
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106753457
Lab 1 - 2
PLC Short Course
IN-1
IN-3
IN-5
IN-7
IN-9
IN-11
IN-13
IN-15
GND-0
IN-17
IN-19
IN-21
IN-23
IN-25
IN-27
IN-29
IN-31
GND-1
+
DC
Power
Supply
-
2
1
4
3
6
5
8
7
10
9
12
11
14 13
16 15
18 17
20 19
22 21
24 23
26 25
28 27
30 29
32 31
34 33
36 35
IN-0
IN-2
IN-4
IN-6
IN-8
IN-10
IN-12
IN-14
GND-0
IN-16
IN-18
IN-20
IN-22
IN-24
IN-26
IN-28
IN-30
GND-1
Fig. 1. Example ControlLogix IB32 DC Input Module Connection Diagram.
Jumper
Bar
+
DC
Power
Supply
DC-0(+)
DC-1(+)
DC-2(+)
DC-3(+)
DC-4(+)
DC-5(+)
DC-6(+)
DC-7(+)
DC-8(+)
DC-9(+)
DC-10(+)
DC-11(+)
DC-12(+)
DC-13(+)
DC-14(+)
DC-15(+)
DC-15(+)
Not used
2
1
4
3
6
5
8
7
10
9
12
11
14 13
16 15
18 17
20 19
22 21
24 23
26 25
28 27
30 29
32 31
34
33
36 35
OUT-0
OUT-1
OUT-2
OUT-3
OUT-4
OUT-5
OUT-6
OUT-7
OUT-8
OUT-9
OUT-10
OUT-11
OUT-12
OUT-13
OUT-14
OUT-15
Not used
Not used
Fig. 2. Example ControlLogix OB36I DC Output Module Connection Diagram.
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106753457
Lab 1 - 3
PLC Short Course
+
DC
Power
Supply
-
A
B
C
D
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
E
Not used
Not used
Not used
Not used
Input 00
Input 07
Input 10
Input 17
DC Common
Fig. 3. Example PLC-5 IBD DC Input Module Connection Diagram.
+
DC
Power
Supply
-
A
B
C
D
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
E
DC+
DC+
DC+
DC+
Output 00
Output 07
Output 10
Output 17
DC Common
Fig. 4. Example PLC-5 OBD DC Output Module Connection Diagram.
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Lab 1 - 4
PLC Short Course
+
DC
Power
Supply
-
In 00
In 02
In 04
In 06
In 08
In 10
In 12
In 14
DC Com
In 01
In 03
In 05
In 07
In 09
In 11
In 13
In 15
DC Com
Fig. 5. Example SLC-500 IB16 DC Input Module Connection Diagram.
+
DC
Power
Supply
-
DC+
Out 01
Out 03
Out 05
Out 07
Out 09
Out 13
Out 15
Out 00
Out 02
Out 04
Out 06
Out 10
Out 12
Out 14
DC Com
Fig. 6. Example SLC-500 OB16 DC Output Module Connection Diagram
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106753457
Lab 1 - 5
PLC Short Course
DC+
(or L1)
DC Common
(or L2)
Start_PB
LA1
Stop_PB
LA2
SW3
LA3
SW4
LA4
LA5
Fig. 7. Switch and light board connections.
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106753457
Lab 1 - 6
PLC Short Course
II. Series Operation (Logical AND)
Two switches in series are used to control a lamp load. The circuit and the corresponding
ladder logic is shown in Fig. 8. The input and output addresses are shown in the ladder logic. If
programming using the ControlLogix, follow the instructions in parts A. and D. below to set up
the processor and enter the program. If programming using the PLC-5, follow the instructions in
parts B. and D. below. If programming the SLC-500, follow the instructions in parts C. and D.
below. Demonstrate the PLC operation to the instructor.
LA1
SW 3
SW3
SW 4
SW4
LA1
Fig. 8. Series switch circuit and its ladder logic equivalent.
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106753457
PLC Short Course
Lab 1 - 7
A. STARTING A PROJECT WITH THE CONTROLLOGIX
Wire the switch/light board before proceeding. Power up the computer, the PLC rack, and
external power supply, as needed. Turn the key on the PLC to the REM (middle) position.
If RSLinx is not already started, then start the program. If the RSLogix5000
Programming Software main menu is not already displayed, click on the RSLogix5000 icon.
The main menu screen should appear with a list of selections. If the error message "Project file
does not exist! OK to create it?", click on "Yes". The software will start up in the offline mode
and a ladder may be displayed.
Communications should already be set up properly. To check that they are properly
configured, select Communications | Who Active. Click on "+" box next to "AB_DF1-1" since
the Logix5550 is connected with a serial cable to the PC. A processor icon should appear with
"1756-L1/A LOGIX5550" and maybe a name of the current program in the processor. Click on
Close.
If your project is already in the PLC, click on the down arrow beside the small window
in the upper left (should have "OFFLINE") and select Go Online. A ladder diagram should
appear. Skip to the online programming functions.
When starting a project for the first time, it is best to initially set it up offline, and then go
online. The initial setup consists of specifying the processor and configuring the discrete I/O
modules.
1. Configuring the Processor
When starting a project for the first time, check and make sure the OFFLINE/ONLINE
window displays "No Controller". From the menu bar select File | New, or click on the paper
sheet icon. If you are prompted to close the current project, select Yes. A window titled "New
Controller" is displayed. Type in a controller name. Select the proper chassis type (7- or 10-slot)
and slot for the processor (probably "0"). Select the proper directory in which the project will be
saved (Should be "C:\Projects\RSLogix 5000"). Click on OK. The project data bases will be
created. A project window and a large blank area will appear.
Set up project communications. On the main menu bar, select Communications | Who
Active. Click on "+" box next to "AB_DF1-1" since the Logix5550 is connected with a serial
cable to the PC. Select line with "1756-L1/A LOGIX5550". Check box "Apply Current Path to
Project". Click on Apply. Click on Close.
You are now ready to configure the I/O channels. The OFFLINE/ONLINE window
displays "Offline".
2. I/O Configuration
Using the RSLogix software, configuration of the inputs and outputs involves two steps:
1.
2.
specifying modules in the rack
assigning tags to the I/O channels
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106753457
Lab 1 - 8
PLC Short Course
The second step is not absolutely necessary, but it is easier to specify symbols now than when
programming the ladder logic. The RSLogix programming software aids the programming of a
PLC because one does not need to memorize the I/O addresses and file addresses, but can refer
to them symbolically, as a label.
Right-click on the I/O Configuration folder in the project tree. A pop-up window will
appear. Select New Module... A window titled "Select Module Type" will appear. To specify the
I/O modules,
In the main part of the window, a list of available modules is displayed. Click on the
type of module in slot 1 (a 1756-IB32/A)
Click on OK.
A window titled "Module Properties" will appear. Enter a name for the module
(Suggestion: digital_in). Verify that the slot number is correct (slot 1) and make
sure Comm Format is "Input Data".
Click on Finish >> to accept the default module configuration..
Slot 1 is now configured for a 32 point discrete input module.
Right-click on the I/O Configuration folder in the project tree and add a 1756-OB16I.
The steps are similar to the steps to add the discrete input module. Make sure the module name is
different from the discrete input module. The Comm Format should be "Output Data".
The I/O Configuration folder should have the following subitems:
[1] 1756-IB32/A discrete_in
[2] 1756-OB16I discrete_out
Now assign tags to the input channels. Double-click on the Controller Tags folder in the
project tree window. The Controller Tags window will appear. To assign symbols to the discrete
input channels,
Click on the Edit Tags tab.
A table will appear with a white last row. New tags are entered in the last (white) row.
Type your tag name, in this case "Start" in the Tag Name column and press <Tab>.
Click on the down arrow in the Alias For column.
Click on "Local:1:I" and click on the "+" to display the members of this structure.
Click on "Local:1:I.Data" and then on the down arrow.
Click on the proper bit ("0" in this case).
Click on the entry for the Description. The Type for "Start_PB" should change to
BOOL. Type in a description in the box, for example, "Start push button switch" and
then click back on the box in the Description column.
Repeat the above 6 steps to specify the tags and descriptions for the other input and
output channels.
Now some of the other tags need to be defined.
3. Specifying Other Tags
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PLC Short Course
Lab 1 - 9
It is good practice to enter all of the tags (variables) before you start programming. If you
enter a rung with undefined tags, errors will be reported. At that point, you can enter new tags
into the program and clear the verify errors.
In a similar manner as done for the I/O tags, type in tags for a few timers, counters, and
booleans.
For timers, the data type is TIMER.
For counters, the data type is COUNTER.
For booleans, the data type is BOOL
Now the processor channel information must be specified.
4. Processor Channel Configuration
For the Logix5550, the baud rate of the serial port must be set to match the baud rate in
the RSLogix communication configuration.
Right-click on the Controller (top line) folder in the project tree window.
Select Properties
Select the Serial Port tab
Make sure the baud rate is 19200.
Click on OK when finished.
Now the processor needs to be downloaded with the blank ladder.
5. Processor Download
Click on the down arrow in the OFFLINE/ONLINE window. Select Download. A
Download window will pop up. Click on Download. If a window pops up informing you that the
communication configuration is different, click on Don't Apply. If a Save Project window
appears, click on OK.
When a windows pops up and asks if you want to go Online, click on Yes. Skip to the
online editing functions, section D1.
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Lab 1 - 10
PLC Short Course
B. STARTING A PROJECT WITH THE PLC-5
Wire the switch/light board before proceeding. Power up the computer, the PLC rack, and
external power supply, as needed. Turn the key on the PLC to the REM (middle) position.
If RSLinx is not already started, then start the program. If the RSLogix5 Programming
Software main menu is not already displayed, click on the RSLogix5 icon. The main menu
screen should appear with a list of selections. If the error message "Project file does not exist!
OK to create it?", click on "Yes". The software will start up in the offline mode and a ladder may
be displayed.
Communications should already be set up properly. To check that they are properly
configured, select Comms | System Comms.... Click on "+" box next to "AB_DF1-1" since the
PLC-5 is connected with a serial cable to the PC. A processor icon should appear with "PLC5/xx" and maybe a name of the current program in the processor. Click on OK.
If your project is already in the PLC, click on the down arrow beside the small window
in the upper left (should have "OFFLINE") and select Go Online. A ladder diagram should
appear. Skip to the online programming functions.When starting a project for the first time, it is
best to initially set it up offline, and then go online. The initial setup consists of specifying the
processor and configuring the discrete I/O modules.
1. Configuring the Processor
When starting a project for the first time, check and make sure the OFFLINE/ONLINE
window displays OFFLINE. From the menu bar select File | New, or click on the white sheet
icon. If you are prompted to close the current project, select Yes. A window titled "Select
Processor Type" is displayed. Type in a project name and select the proper Platform, Processor
and Series/Revision. The processor model is indicated on the front of the processor model,
toward the very bottom of the front. The current processors, and their platform type is listed in
the table below. The memory size is fixed and there is only one selection.
Processor
PLC5/11
PLC5/12
PLC5/20
PLC5/20E
PLC5/25
Platform
Enhanced
Original
Enhanced
Ethernet
Original
Series
C or D
A
C
C
A
Click on Who Active.. to set up project communications. Click on "+" box next to
"AB_DF1-1" since the PLC is connected with a serial cable to the PC. Select the line with "PLC5/xx". Click on OK.
When finished, click on OK. The project data bases will be created. A project window
and an empty ladder will appear. You are now ready to configure the I/O channels.
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Lab 1 - 11
PLC Short Course
2. I/O Configuration
For the PLC-5, specification of the I/O configuration is optional. Using the RSLogix
software, configuration of the inputs and outputs involves two steps:
1.
specifying modules in the rack
2.
assigning symbols to the I/O channels
The second step is not absolutely necessary, but it is easier to specify symbols now than when
programming the ladder logic. The RSLogix programming software aids the programming of a
PLC because one does not need to memorize the I/O addresses and file addresses, but can refer
to them symbolically, as a label.
Double-click on the IO Configuration icon in the project tree. A window titled "Chassis
Table" will appear. For the lab, only one chassis is used, and one should be displayed. The
chassis type should be 4 slots or 8 slots (check your chassis) and the Rack Addressing should be
"1 Slot". To change the chassis type or rack addressing,
Right-click on any field on the chassis row
Click on Properties
Change the chassis type to the proper one (4 slot or 8 slot)
Change the rack addressing to "1-slot"
Click OK
To display the chassis configuration,
Right-click on any field on the chassis row
Click on Display Chassis
Depending on whether 120 vAC or low voltage DC discrete I/O cards are in your PLC, the I/O
Module System Configuration should appear as below (check the sheet that lists the I/O
modules for each PLC for last minute changes):
Low voltage DC Modules:
Slot
0
1
2
R/G/S/C
0/0/0/0
0/1/0/0
0/2/0/0
Module Type
I/O Points
Description
1771-IBD
1771-OBD
16
16
10-30v DC 16 pt Input
10-60v DC 16 pt Output
Module Type
I/O Points
Description
1771-IAD
1771-OAD
16
16
120v AC 16 pt Input
120v AC 16 pt Output
120 v AC Modules:
Slot
0
1
2
R/G/S/C
0/0/0/0
0/1/0/0
0/2/0/0
If the module configuration is not correct, you will need to insert and/or delete modules to
modify the configuration that exists.
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Lab 1 - 12
PLC Short Course
To delete a module:
Right-click on the entry in the "Module" column (a box surrounds it) Click on Delete
Module. The "Detach" radio button should be selected and confirm by clicking on
Delete.
To insert a module:
Double-click on the "Module" column for the appropriate row and a window with all
possible I/O modules will appear.
Use the scroll bar on the side to display the proper module and single-click on it.
(Note: you may just type the proper module type (IAD, OAD, IBD, or OBD) and
<Enter>)
It will appear in the chassis overview.
Close the chassis configuration and I/O Configuration windows by clicking in the "X" in
the upper right corner of the window.
Now assign symbols to the input channels. Double-click on the Address/Symbol icon in
the project tree window. The Address/Symbol Editor window will appear. To assign symbols to
the discrete input channels,
Click on Add New Record
A blank box will appear in the Address column of the table. Type in an address in the
format (for START_PB switch) "I:1/00" and press <Tab>. A new row appears in the
address table and columns labeled "Symbol" and "Description" will appear and the
cursor will be in the "Symbol" column. You will only need to enter information in the
"Symbol" column. The "Description" column is optional, though for a real program,
you will generally place up to 75 characters of additional descriptive text in this field.
If the cursor is not already in the "Symbol" column, click on the symbol column next to
address I:001/00 (or use the cursor keys to place the box in this position).
Type your symbol name, in this case "START_PB" and press <Enter>.
Use the <Tab> or mouse to move the box to the description column and type in a
description, for example, "Start push button switch" and then press <Enter> <Enter>.
Repeat the above 3 steps to specify the symbols and descriptions for the other input and
output channels.
When finished, close the window by clicking on the "X" in the upper right corner of the
window.
Now some of the data files need to be re-sized.
3. Sizing Data Files
It is good practice to properly size the data files before you start programming, since you
will not be allowed to resize the data files when programming if the processor is in the Run
mode. The default data files have only one element, which is not enough for the labs. The B3,
T4, and C5 files will be sized to contain 11 elements, numbered from 0-10.
In the project tree window, right-click on the icon for "B3 - BINARY".
Click on Properties
Change the Elements field to "11" and press <Enter>.
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PLC Short Course
Lab 1 - 13
Right-click on the icon for "T4 - TIMER".
Click on Properties, change the Elements field to "11" and press <Enter>.
Right-click on the icon for "C5 - COUNTER".
Click on Properties, change the Elements field to "11" and press <Enter>.
Now the processor channel information must be specified.
4. Processor Channel Configuration
For the enhanced and Ethernet PLC-5’s (PLC-5/11, 5/20, 5/20E), the baud rate of the
serial port must be set to match the baud rate in the RSLogix communication configuration.
Double-click on the Channel Configuration in the project tree window. Make sure the baud rate
is 19200. Click on OK when finished.
Now the processor needs to be downloaded with the blank ladder.
5. Processor Download
Select Comms | Download.... If a window pops up indicating a mismatch in the
processor revision letter, click on Yes. The next window will confirm the change in processor
type. Make sure "Resize Data Tables" is checked and then click on OK. If a Save Project window
appears, click on OK.
When a windows pops up and asks if you want to go Online, click on Yes. Skip to the
online editing functions, section D2.
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PLC Short Course
C. STARTING A PROJECT WITH THE SLC-500
Power up the computer, PLC rack, and external power supply. Turn the key on the PLC
to the REM (middle) position.
For the most part, programming the SLC-500 series of PLC processors is identical to
programming the PLC-5 processors. The major differences in the programs are:



The SLC-500 I/O channels are numbered in decimal (versus octal for the PLC-5).
The SLC-500 has no slots numbered zero.
The SLC-500 instruction set is very close to the original PLC-5 processors.
In general, the SLC-500 programming software has a few less features than the PLC-5
programming software. The major differences that one will see are:



The I/O configuration must be specified before downloading the initial project and going
on-line.
Only the SLC 5/04 and 5/05 support on-line editing. For all others, one must edit ladder
off-line and download changed program to PLC.
Cannot increase size of data tables when editing on-line (only applies to the SLC 5/04
and 5/05 which are the only ones that allow on-line editing)
For the most part the procedure to start a project is the same as for the PLC-5.
If RSLinx is not already started, then start the program. If the RSLogix500 Programming
Software main menu is not already displayed, click on the RSLogix500 icon. The main menu
screen should appear with a list of selections. If the error message "Project file does not exist!
OK to create it?", click on "Yes". The software will start up in the offline mode and a ladder may
be displayed.
Communications should already be set up properly. To check that they are properly
configured, select Comms | System Comms.... Click on the "+" box next to "AB_DF1-1" since
the SLC-5/xx is connected with a serial cable to the PC. A processor icon should appear with
"SLC-5/xx" and maybe a name of the current program in the processor. Click on OK.
If your project is already in the PLC, click on the down arrow beside the small window
in the upper left (should have "OFFLINE") and select Go Online. A ladder diagram should
appear. Skip to the online programming functions.
When starting a project for the first time, it must initially be set up offline, and then go
online. The initial setup consists of specifying the processor and configuring the discrete I/O
modules.
1. Configuring the Processor
When starting a project for the first time, check and make sure the OFFLINE/ONLINE
window displays OFFLINE. From the menu bar select File | New, or click on the white sheet
icon. If you are prompted to close the current project, select Yes. A window titled "Select Project
Name" is displayed. Check with the lab instructor as to which processor to select (the model
number is not on the front of the processor). It will be one of the following:
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106753457
PLC Short Course
Lab 1 - 15
1747-L542B 5/04 CPU - 32K Mem OS401.
1747-L551B 5/05 CPU - 16K Mem OS501 Series C.
Type in a Processor (project) name and click on OK. The project data bases will be created. A
project window and an empty ladder will appear. You are now ready to configure the I/O
channels.
2. I/O Configuration
Using the RSLogix software, configuration of the inputs and outputs involves two steps:
1. specifying modules in the rack
2. assigning symbols to the I/O channels
The second step is not absolutely necessary, but it is easier to specify symbols now than when
programming the ladder logic. The RSLogix programming software aids the programming of a
PLC because one does not need to memorize the I/O addresses and file addresses, but can refer
to them symbolically, as a label.
Double-click on the IO Configuration icon in the project tree. A window titled "I/O
Configuration" will appear. You may need to increase the size of the window in order to see the
rack slots. For the lab, only one rack is used. Change rack 1 to be a 1746-A7 7-slot rack. Slot 0
of the rack should already have the proper processor. To specify the I/O modules,
In the right side of the window, a list of available modules is displayed. Click on the type
of module in slot 1 (use a 1746-I*16 )
While holding down the mouse button, drag the module to slot 1 of the rack.
Release the mouse button.
Slot 1 is now configured for any 16 point discrete input module.
Click on the type of module in slot 2 (use a 1746-O*16 )
While holding down the mouse button, drag the module to slot 2 of the rack.
Release the mouse button.
Slot 2 is now configured for any 16 point discrete output module.
Close the I/O Configuration window by clicking in the "X" in the upper right corner of the
window.
Now assign symbols to the input channels. Double-click on the Address/Symbol icon in
the project tree window. The Address/Symbol Editor window will appear. To assign symbols to
the discrete input channels,
Click on Add New Record
A blank box will appear in the Address column of the table. Type in an address in the
format (for START_PB switch) "I:1/00" and press <Tab>. A new row appears in the
address table and columns labeled "Symbol" and "Description" will appear and the
cursor will be in the "Symbol" column. You will only need to enter information in the
"Symbol" column. The "Description" column is optional, though for a real program,
you will generally place up to 75 characters of additional descriptive text in this field.
If the cursor is not already in the "Symbol" column, click on the symbol column next to
address I:001/00 (or use the cursor keys to place the box in this position).
Type your symbol name, in this case "START_PB" and press <Enter>.
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Lab 1 - 16
PLC Short Course
Use the <Tab> or mouse to move the box to the description column and type in a
description, for example, "Start push button switch" and then press <Enter> <Enter>.
Repeat the above 3 steps to specify the symbols and descriptions for the other input and
output channels.
When finished, close the window by clicking on the "X" in the upper right corner of the
window.
Now some of the data files need to be re-sized.
3. Sizing Data Files
It is good practice to properly size the data files before you start programming, since you
will not be allowed to resize the data files when programming on-line. The default data files have
only one element, which is not enough for the labs. The B3, T4, and C5 files will be sized to
contain 11 elements, numbered from 0-10.
In the project tree window, right-click on the icon for "B3 - BINARY".
Click on Properties
Change the Elements field to "11" and press <Enter>.
Right-click on the icon for "T4 - TIMER".
Click on Properties, change the Elements field to "11" and press <Enter>.
Right-click on the icon for "C5 - COUNTER".
Click on Properties, change the Elements field to "11" and press <Enter>.
Now the processor channel information must be specified.
4. Processor Channel Configuration
For the SLC-5/03, SLC-5/04 and SLC-5/05, the baud rate of the serial port must be set to
match the baud rate in the RSLogix comm configuration.
Double-click on the Channel Configuration in the project tree window.
Select the Chan. 0 - System tab
Set the baud rate to 19200.
Select the Chan. 0 - User tab
Set the baud rate to 19200.
Click on OK when finished.
Now the processor needs to be downloaded with the blank ladder.
5. Processor Download
Select Comms | Download.... A revision note window may pop up. Either type in a note,
or just click on OK. If a window pops up indicating a mismatch in the processor revision letter,
click on Yes. A confirmation window will pop up. Click on Yes. If a window pops up informing
you that the communication confguration is different, click on Don't Apply. If a Save Project
window appears, click on OK.
When a window pops up and asks if you want to go Online, click on Yes.
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LA1
SW 3
SW3
SW 4
SW4
LA1
Fig. 8. Series switch circuit and its ladder logic equivalent.
D. PROGRAMMING THE SERIES CIRCUIT
1. RSLogix5000 for ControlLogix
The OFFLINE/ONLINE box should show "REMOTE PROG" backlighted in blue. The
steps necessary to program the first part of the experiment, the series rung, will be explained in
detail. For the other parts of the exercise, only the different steps required to do these parts are
explained.
The first ladder program to be implemented will be a simple series control rung. Two
switches, SW3 and SW4, will be placed in series and will be used to control a single light, LA1.
Use the right mouse button to access editing functions whenever possible. Clicking on the
right mouse button brings up the editing menu with available options. The menu is different
depending on the (box) cursor location. If the box is on the left rail of a rung, rung editing
functions: accept, cancel, cut, paste, append rung, insert rung, etc. If the box is on an instruction,
then instruction editing functions are presented if the right mouse button is clicked:
append/insert instruction, insert/append branches, change instruction type, cut, paste, etc. As you
place the instructions into a ladder program, one can either append or insert the instruction.
Append places the new instruction to the right of the current cursor position, and insert places the
instruction to the left. If the cursor is on the left power rail, append or insert will append or insert
a rung. Appended rungs are placed below the current rung, and inserted rungs are placed above
the current rung.
If ladder window is not displayed, double-click on “MainRoutine” under “Main Task” in
the project window. Place the cursor (blue box) on the END rung. If not, click on the left rail of
the bottom rung.
Click on the Insert Rung icon (├─┤). A new rung appears at the top of the screen with a
blue box on the left. The "e" in the box indicates this is an edit zone. Now the
individual instructions for the new rung will be entered.
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A normally open (NO) relay contact is needed at the input, so click on the appropriate
contact symbol (┤├) above the ladder window.
Move the cursor arrow tip close to the left side of the rung and click the mouse. The NO
contact will appear with a box around it and a question mark above it.
Switch SW3 will be used first, so type the tag for that switch ("SW3") and press <Enter>.
The symbolic and physical address of the relay that controls the contact will appear
above the contact symbol on the ladder diagram.
Click on the ┤├ contact symbol above the ladder window and then click on the new rung
to the right of the first contact and add a second NO relay in series with the first. Use
the symbol or address for switch SW4 ("SW4") for this contact.
The output for this rung will be light LA1.
Click on the output coil symbol (-( )-) above the ladder window.
Move the cursor to the right side of the rung and click the mouse. A normal output coil
symbol will appear with a box above it.
Type the symbol or address for light LA1 ("LA1").
Since the output instruction has been entered, the rung edits may now be accepted.
Click on the left rail of the rung. A blue box appears.
Click the right mouse button.
Click on Accept Rung Edits. Now the rung is loaded into the controller's memory. The
"e" indications on the left side of the rung should disappear.
To change the processor to the run mode use the following keystrokes:
Click on the arrow to the right of "REMOTE PROG" box
Click on Run
Click on Yes
The controller is now set to respond to input conditions and perform appropriate output
commands. The ladder power rails change to green, indicating the processor in the run mode.
Try the input switches in various combinations and observe the output. Also observe the
changing status of ladder components on the screen. Energized or true conditions cause the
elements to be highlighted on the ladder diagram.
2. RSLogix for PLC-5/SLC-500
The OFFLINE/ONLINE box should show "REMOTE PROG" backlighted in blue. The
steps necessary to program the first part of the experiment, the series rung, will be explained in
detail. For the other parts of the exercise, only the different steps required to do these parts are
explained.
The first ladder program to be implemented will be a simple series control rung. Two
switches, SW3 and SW4, will be placed in series and will be used to control a single light, LA1.
Use the right mouse button to access editing functions whenever possible. Clicking on the
right mouse button brings up the editing menu with available options. The menu is different
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PLC Short Course
Lab 1 - 19
depending on the (box) cursor location. If the box is on the left rail of a rung, rung editing
functions: accept, cancel, cut, paste, append rung, insert rung, etc. If the box is on an instruction,
then instruction editing functions are presented if the right mouse button is clicked:
append/insert instruction, insert/append branches, change instruction type, cut, paste, etc. As you
place the instructions into a ladder program, one can either append or insert the instruction.
Append places the new instruction to the right of the current cursor position, and insert places the
instruction to the left. If the cursor is on the left power rail, append or insert will append or insert
a rung. Appended rungs are placed below the current rung, and inserted rungs are placed above
the current rung.
If the ladder window is not displayed, double-click on “LAD 2” under “Program Files” in
the project window. Place the cursor (red box) on the END rung. If not, click on the left rail of
the bottom rung.
Click on the Insert Rung icon (…├─┤). A new rung appears at the top of the screen with
a red box on the left. The "e" in the box indicates this is an edit zone. Now the
individual instructions for the new rung will be entered.
A normally open (NO) relay contact is needed at the input, so click on the appropriate
contact symbol (┤├) above the ladder window.
Move the cursor arrow tip close to the left side of the rung and click the mouse. The NO
contact will appear with a box around it and a question mark above it.
Switch SW3 will be used first, so type the symbol or address for that switch ("SW3" or
"I:1/02") and press <Enter>. The symbolic and physical address of the relay that
controls the contact will appear above the contact symbol on the ladder diagram.
Click on the ┤├ contact symbol above the ladder window and then click on the new rung
to the right of the first contact and add a second NO relay in series with the first. Use
the symbol or address for switch SW4 ("SW4" or "I:1/03") for this contact.
The output for this rung will be light LA1.
Click on the output coil symbol (-( )-) above the ladder window.
Move the cursor to the right side of the rung and click the mouse. A normal output coil
symbol will appear with a box above it.
Type the symbol or address for light LA1 ("LA1" or "O:2/00").
Since the output instruction has been entered, the rung edits may now be accepted.
Click on the left rail of the rung. A red box appears.
Click the right mouse button.
Click on Accept Rung Edits. Now the rung is loaded into the controller's memory. The
"e" indications on the left side of the rung should disappear.
To change the processor to the run mode use the following keystrokes:
Click on the arrow to the right of "REMOTE PROG" box
Click on Run
Click on Yes
The controller is now set to respond to input conditions and perform appropriate output
commands. The ladder power rails change to green, indicating the processor in the run mode.
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Try the input switches in various combinations and observe the output. Also observe the
changing status of ladder components on the screen. Energized or true conditions cause the
elements to be highlighted on the ladder diagram.
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III. Parallel Operation (Logical OR)
Connect two switches in parallel, as shown in Fig. 9, which is a logical OR condition.
The instructions to program the PLC are below. Demonstrate the PLC operation to the
instructor.
LA1
SW 3
SW 4
Fig. 9. Parallel switch circuit.
1. RSLogix for ControlLogix
Change the processor back to program mode:
Click on the arrow to the right of "REMOTE RUN" box
Click on Program
Click on Yes
Either insert a new rung, or start rungs edits on an existing rung, placing the cursor on the
instruction that will parallel the new branch. To start the branch:
Place the cursor on the contact that will parallel the new branch.
Click on the branch icon (looks like a “branch”) above the ladder window or right click
the mouse and select Insert New Branch
A branch will appear to the right of the cursor with a blue box surrounding the right side
of the branch
Place the mouse cursor on the blue box and hold down the mouse button as you drag the
branch to the desired location of this side of the branch, usually on the other side of
an instruction. The blue oval on the rung that changes to green indicates the location
of this branch leg. Release the mouse button and the program will place the branch.
Instructions are entered on branches just as if they were a separate rung.
To make a series of parallel branches that have parallel sides (instead of nesting, which
looks like an inverted tree), the branch is extended down.
Place the cursor on the lower left corner of the branch.
Right click the mouse
Select Extend Branch Down
A branch will appear below the existing branch and parallel with the existing branch
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PLC Short Course
2. RSLogix for PLC-5/SLC-500
Change the processor back to program mode:
Click on the arrow to the right of "REMOTE RUN" box
Click on Program
Click on Yes
Either insert a new rung, or start rungs edits on an existing rung, placing the cursor on the
instruction that will parallel the new branch. To start the branch:
Place the cursor on the contact that will parallel the new branch.
Right click the mouse.
Select Insert New Branch
A branch will appear before the cursor with a red box surrounding the right side of the
branch
Place the mouse cursor on the red box and hold down the mouse button as you drag the
branch to the desired location of the right side of the branch, usually on the other side
of an instruction. The red rectangular box on the rung that changes to green indicates
the location of the other leg of the branch. Release the mouse button and the program
will place the branch.
Instructions are entered on branches just as if they were a separate rung.
To make a series of parallel branches that have parallel sides (instead of nesting, which
looks like an inverted tree), the branch is extended down.
Place the cursor on the lower left corner of the branch.
Right click the mouse
Select Extend Branch Down
A branch will appear below the existing branch and parallel with the existing branch
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PLC Short Course
Lab 1 - 23
IV. Motor Start/Stop
Using the Start and Stop switches and one lamp, implement a motor start/stop circuit.
The start switch is a normally open pushbutton switch and the stop switch is a normally closed
pushbutton switch. Demonstrate the PLC operation to the instructor.
V. Timer Operation
Devise a ladder logic program to do the following:
a. When a switch is closed, one lamp lights.
b. Five seconds later, another lamp lights.
Demonstrate the PLC operation to the instructor.
1. RSLogix for ControlLogix
To enter a timer into a rung, position the cursor on the right side of the rung, or to the left
of where you want to place the instruction.
Click on the Timer/Counter tab above the ladder window and click on TON.
A timer instruction will appear at the right side of the rung. A box with a cursor will
appear.
Type the tag in the “Timer” field and press <Enter>
Type the preset value and press <Enter>
Type the initial accumulator value and press <Enter>
Other types of timer instructions are selected by clicking on the Timer/Counter tab and
then the appropriate mnemonic (TON, TOF, RTO, or RES (reset timer)).
Note: to refer to the timer done bit in a contact address, use "timer_tag.DN".
2. RSLogix for PLC-5/SLC-500
To enter a timer into a rung, position the cursor on the right side of the rung, or to the left
of where you want to place the instruction.
Click on the Timer/Counter tab above the ladder window and click on TON.
A timer instruction will appear at the right side of the rung. A box with a cursor will
appear.
At this point, you have two options:
1. Type the timer address, e. g., "T4:1", and press <Enter>
2. Type a symbolic name, e. g., "TIMERA" and press <Enter>. If an address has not
already been assigned to this symbol, then a warning message will appear at the
bottom of the screen. You will have to use the database symbol/description to
assign the symbol. Your rung edits will not be accepted until you assign an
address to that symbol. Click on the symbolic name to highlight it. Now double
click on Database-Address/Symbol in the project tree window. The record for the
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symbol will appear, allowing you to type in an address, followed by <Enter>.
Click on the icon in the upper right to finish with the address/symbol editor.
Select the timer base, 0.01 or 1 second and press <Enter>
Type the preset value and press <Enter>
Type the initial accumulator value and press <Enter>
Other types of timer instructions are selected by clicking on the Timer/Counter tab and
then the appropriate mnemonic (TON, TOF, RTO, or RES (reset timer)).
Note: to refer to the timer done bit in a contact address, use "symbol.DN" or
"address.DN".
VI. Counter Operation
Devise a ladder logic program to do the following:
When a switch is closed five times, one lamp lights.
Demonstrate the PLC operation to the instructor.
1. RSLogix for ControlLogix
Counter blocks are placed in the ladder rung in much the same way as timers. To enter
an up counter into a rung, first click on the CTU and position the arrow on the right side of the
rung.
Click the mouse.
A CTU instruction will appear at the right side of the rung. A box with a cursor will
appear.
Type the tag in the “Counter” field and press <Enter>
Type the preset value and press <Enter>
Type the initial accumulator value and press <Enter>
For other types of counter instructions are selected by clicking on the Timer/Counter tab
and then the appropriate mnemonic (CTU, CTD, or RES (reset timer)).
Note: to refer to the counter done bit in a contact address, use "counter_tag.DN".
2. RSLogix for PLC-5/SLC-500
Counter blocks are placed in the ladder rung in much the same way as timers. To enter
an up counter into a rung, first click on the CTU and position the arrow on the right side of the
rung.
Click the mouse.
A CTU instruction will appear at the right side of the rung. A box with a cursor will
appear.
At this point, you have two options:
1. Type the counter address, e. g., "C5:1" and press <Enter>
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Lab 1 - 25
2. Type a symbolic name, e. g., "COUNTA" and press <Enter>. If an address has
not already been assigned to this symbol, then a warning message will appear at
the bottom of the screen. You will have to use the database symbol/description to
assign the symbol. Your rung edits will not be accepted until you assign an
address to that symbol. Click on the symbolic name to highlight it. Now double
click on Database-Address/Symbol in the project tree window. The record for the
symbol will appear, allowing you to type in an address, followed by <Enter>.
Click on the icon in the upper right to finish with the address/symbol editor.
Type the preset value and press <Enter>
Type the initial accumulator value and press <Enter>
For other types of counter instructions are selected by clicking on the Timer/Counter tab
and then the appropriate mnemonic (CTU, CTD, or RES (reset timer)).
Note: to refer to the counter done bit in a contact address, use "symbol.DN" or
"address.DN".
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VII. Flashing Lights.
Devise ladder logic using two lamps and two timers to make the two lamps flash
alternately. Choose any on/off period. Use one of the switches to turn the flashing lights on and
off. Demonstrate the PLC operation to the instructor. You will need to use this ladder logic for
the heating and ventilation lab exercise.
VIII. One-Shot Pulse.
Devise ladder logic using the start switch, one lamp, and one timer to produce a five
second one-shot signal (indicated by the lamp). When the start switch is pressed, the lamp
should light for five seconds and then turn off. Pressing the start switch should have no effect
when the light is on (the light should not go out, nor should the light remain on any longer).
When the lamp turns OFF, another press of the start switch should start the process over. If the
start switch is held down, the lamp should light for five seconds and turn off. The lamp should
not turn on until the start switch is released and pressed again. Demonstrate the PLC operation
to the instructor. You will need to use this ladder logic for the conveyor lab exercise.
IX. Turn Signal.
Devise ladder logic using SW3 and SW4 and timers to produce a turn signal indication
(like the old Thunderbirds) with the five lamps. If SW3 is on, the lights should flash to show a
left turn. The sequence should be ●●●●○, ●●●○○, ●●○○○, ●○○○○, ○○○○○, ●●●●●
(where ○ means a lamp is on and ● means lamp off). If SW4 is on, the lights should flash to
signal a right turn. The right turn sequence should be ○●●●●, ○○●●●, ○○○●●, ○○○○●,
○○○○○, ●●●●●. If both switches are on, then no lamps should flash. The patterns should repeat
as long as either switch is on. Each "pattern" in the sequence should be displayed. There should
be a time interval for which no outputs are on. Choose any reasonable timing intervals.
Demonstrate the PLC operation to the instructor.
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Lab 1 - 27
X. Cereal Box Filler Example.
Enter the ladder logic for the cereal box filling operation used as a class example. The
following description is the same as used in class, except the timer values are changed. The reset
switch does not exist, and will be simulated by using the forcing function of the RSLogix or
Concept software (the switch/lighting board has only 4 switches). The RSLogix and Concept
chapters explain how to force inputs. You will be required to manually change the limit switch
and the weight sensor switch (SW3 is limit switch, SW4 is the weight sensor). Demonstrate the
PLC operation to the instructor. Put comments in your ladder.
Design a ladder logic diagram to control for the following bottler machine. A figure of
the system is shown below. Upon initial startup, motor M1 runs until an empty box is the
proper position, which is detected by the limit switch, LS. Wait 2.0 seconds and then fill
the box until the weight sensor detects a full box. After the box is filled, wait 3.0 seconds
to continue to the next box. If the stop switch is pressed at any time, the box filler is
paused at the current step. When the start switch is pressed while the operation is paused,
the box filler should resume the suspended step. When the box filler is paused, the
motors should be shut off and the filler solenoid should be turned off, and all timer
values should be retained. A separate reset switch is provided which resets the timers and
any internal steps so that when the start switch is pressed, no box is assumed to be in the
filling position. The reset switch should be ignored if the box filler is running. Motor
M2 runs continuously (unless paused).
Assume the following input and output assignments:
CLogix
PLC-5
Tag/Symbol
1:I:Data.0 I:1/00
START_PB
Start pushbutton, N. O., ON when starting
1:I:Data.1 I:1/01
STOP_PB
Stop pushbutton, N. C., OFF when stopping
1:I:Data.2 I:1/02
LS
Limit switch, N. O., ON (closed) when box in
position
1:I:Data.3 I:1/03
WT_SENSE
Weight sensor switch, N. O., ON (closed) when box
full
1:I:Data.4 I:1/04
RESET_PB
Reset, N. O., ON when resetting the internal steps
2:O:Data.0 O:2/00
M1
Motor, ON to run infeed conveyor
2:O:Data.1 O:2/01
M2
Motor, ON to run outfeed conveyor
2:O:Data.2 O:2/02
FILL
Filler solenoid, ON to fill box
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Figure 10. Cereal Box Filling Station
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