"Building HMI with Visual Basic Technologies - 1998". Though they are old slides but still worth having a look especially for those who are new to HMI and SCADA technologies.

1. Building Your HMI Using Visual
Basic Technologies - A Tutorial
John Weber
The Software Toolbox ®
jweber@softwaretoolbox.com
October 21, 1998
Houston, TX Poster Presentation
Copyright 1998 Qualitrol International & Software Toolbox.All rights reserved worldwide.The Software Toolbox is a registered trademark of Qualitrol International.

2. Why are we here today ?
• Take the mystery out of objects and VB
– Objects & terminology
– ActiveX & Containers
– VB - The “Glue”
• Sample Applications
– Process Graphics – Alarming/Logging
– PLC Connections – Recipes
– Networking
– Trending/Logging

3. Defining the Technologies

4. Software Objects
What are they ?
• You can’t touch them - except on the disks or CD you load
them onto your PC from
• You can see them in many cases through their user interface
• Are pieces of software for a specific task or family of similar
tasks
• Are similar to subroutines or functions
• May contain numerous subroutines and functions of their
own
• Used to model software after real-world machine or process
components or sections
• Are easily transported from one PC to another provided
standard interfaces are followed
• Much of the software you use on your PC is built of objects

5. Objects - The Building Blocks
Example - an object representation of a PLC
Input Modules Output
Class Modules Class
Interfaces
Comms.
Output
Output
Output
Input
Input
Input
CPU
Power
Supply PLC Rack

6. Object Terminology
• Classes - groupings of similar object types
• Properties - define how the object behaves
• Methods - make things happen
• Events - occur when things happen
Hypothetical PLC Analog Input Module “class”
Properties - number of channels, voltage level, scaling set points, channel type
Input
Methods - send analog input to CPU, scale value
Events - voltage changed on field input side, scaling updated, updated value sent
to CPU, configuration change received from CPU

7. Object Terminology
A simple software
object - a text box
on a VB form
Properties Methods Events
Alignment Drag Change
BackColor Move Click
BorderStyle OLEDrag DblClick
Font Refresh DragDrop
Height SetFocus DragOver
Name ShowWhatsThis GotFocus
Text and 5 others LostFocus
Visible KeyPress
Width Mousedown
and 43 others Mouseup
and 13 others

8. More Object Terminology
• COM - Component Object Model
• DCOM - Distributed Component Object
Model = COM + Networks
• ActiveX - a type of COM object
• Container - a place you assemble your objects
to form an application
– Office productivity applications
– Development tools - visual basic, etc.
– Web browser
• OLE - Object Linking and Embedding

9. Software Objects Examples
Command
Button
Object
Command
Button
Properties
Everything on your
Excel spreadsheet is an
object! - the worksheet
is a collection of cell
objects, a workbook is
a collection of Cell Cell
worksheet objects Properties Object

10. Software Objects Examples
Invoking the
Print Method
The Print Event

11. Software Objects Examples
Visual Basic (VB)
comes with a lot of
free objects that give
you the Windows look
and feel with minimal
work

12. Software Objects Examples
ActiveX control
objects “plug-in” to
VB to let you add
functionality
• PLC Communications
• Trends
• Gauges
• Tanks

13. Adding an ActiveX Component to
the VB Toolbar & To A Form
Right Mouse
Click with
pointer over
the toolbar
and select
“components”
The Default
VB Toolbar
Double click Check the component
the new you want to add
component on “ABCTL OLE Control
the toolbar module” in this case,
and it is added click the Apply button,
to your form! click the OK button,
and the control is
added to the toolbar

14. An Automation Software Object
Actual PLC Communciations ActiveX
Object “instances” Placed into a
Visual Basic form container
Instance (noun) - a single copy of a type of software
object (I.e. text box or ActiveX control) on a form
Instanciate (verb) - the act of placing a single copy of
an object onto a form

15. Browsing the Object’s
Interfaces
Actual PLC ActiveX object in
a VB container application
where its properties,
methods, and events are
browseable using VB’s
Object Browser Function
Events
Properties
Methods

16. VB - The Glue to connect
objects in your container
• VB - Visual Basic - a full fledged
development environment
• VBA - Visual Basic for Applications
– It is macro language in the Office applications
– Is licensed by over 100 companies for use as their
scripting language for customization
• Both Use simple object.property,
object.method, object_event syntaxes
• VB known by 3,000,000 people worldwide

17. Assembling the Objects in a
Container
Simple Visual Basic Syntax for referring to objects
Properties - ObjectName.Property = variable or value
Methods - Objectname.Methodname (parameters)
Events - Private Sub Objectname_EventName( )
user Logic
End Sub
Example Statements displays text in a text box by setting the
Text1.Text = “Hello World” .Text property on the Text1 text box
object
Sets a PLC memory address property
ABCTL1.FileAddr = “N7:0” (.FileAddr) to read using a plug-in ActiveX
control object
ABCTL1.Autopoll(500) Invokes the .Autopoll Method to read data
every 500ms using a plug-in ActiveX control
object

18. Human Machine Interface Apps
• HMI = Human Machine Interface
• Process Graphics
• PLC Connectivity for Data
• Trending and Logging
• Alarming and Logging
• Recipe Loading
• Networking

19. Process Graphics - Static
Step 1-
Select the
VB image
control from
the VB
toolbar and
add to the
form
Step 2 - Paste an image from a Symbol
Library to the image control, set the stretch
property on the image control to true and
size to fit your needs

20. Process Graphics - Dynamic
Add an instance of
a dynamic gauge
ActiveX plug in to
your VB toolbar
and then to your
form
Right click on the object with your
mouse, select “properties” on the pull
down menu that appears and use this
properties page to set your look and
feel. Here we’ve used a pre-
configured look and feel from the
object’s library to get setup quick

21. PLC Connectivity and Data -
adding the ActiveX Control
Add an off-the-shelf ActiveX
control for PLC connectivity to
your VB toolbar and then add
instances of the control to your VB
form
• Use multiple instances of the PLC ActiveX control to keep code to a minimum
• Give the each instance an intuitive name such as PLCMachine1 and PLCMachine2 in your
applications
• Use separate instances for reading and writing to keep your code to a minimum, even
though most PLC Communications ActiveX controls don’t require you to use separate
instances for reading and writing

22. PLC Connectivity and Data -
setting properties
This particular PLC communications
ActiveX control represents each
physical hardware adapter as a “logical
adapter”. You run a simple config
program shown here to set the hardware
settings and communications
parameters. By doing this, the
developer of this control gives you the
ability to change the hardware interfaces
to your PLC without recompiling your
program.
When you right click on each instance of
the PLC control, you bring up this
properties page to set the properties on the
control for whether you are reading or
writing (.function), the PLC node address
(.node), the PLC memory address
(.Fileaddr), and the number of points to
read/write.

23. PLC Connectivity and Data -
Making the read happen
• Reading occurs when the .Trigger or .Autopoll methods are invoked
• In this example when the Form Loads, (Form_Load() Event) the Autopoll method on
the instance of the PLC ActiveX control called ABCTL1 is invoked.
• The PLC control does its job and when it is done, it fires the “OnReadDone()” event
• Displays are updated using the 3 lines of code shown above in the
ABCTL1_OnReadDone() Event
• Data is accessed in the PLC ActiveX control using the WordVal and BitVal
methods to properly format the data
• Other methods such as floatval, stringval, longval, etc. are available for other
data types

24. Trending and Logging
Builds upon what you’ve
already learned by adding 2
new controls
• Trending ActiveX control
• VB’s standard Data control
for database connectivity
Setup a single instance of the
PLC ActiveX control and its
properties like before but this
time use the standard VB
command button’s On_Click() Properties Page
event to start the polling of the for the Trending
PLC based on user input ActiveX Control

25. Trending and Logging - VB Code
Invoke the PLC ActiveX
Controls’ .Autopoll method to
start/stop polling when user
clicks on command buttons
These lines setup the timebase
and variables on the trend chart
ActiveX control when the form is
loaded
Update text boxes on screen with data
from the PLC ActiveX Control
This OnReadDone Event
Plot data on the trending ActiveX fires every time a poll
control completes - the autopoll rate
sets your trend update rate
Log the data to the database using for you
the VB data controls methods

26. Trending and Logging
The Finished Product in Run Mode

27. Alarming and Logging - Building the Form
• Uses same
controls and
adds one new
• Uses new
methods and
events on PLC
ActiveX VB List Box Control PLC ActiveX
control to for simple alarm VB Data Control Communications
display - new to this for Database
provide alarm project Connectivity
Control
generation
capability

28. Alarming and Logging
Generating the Alarms
• Watchpoint Methods
– Method included in PLC ActiveX control
– User specifies high, low limits and type of alarms
desired (on high, on low, on change, on normal, on
discrete change)
– Autopoll method used to tell control how often to
check the points
• Could all be done with VB If-then structures
• Using the ActiveX controls’ methods instead
saves code and troubleshooting time

29. Alarming and Logging
• You setup the watchpoints and go on
doing other things in your applications
• Handle the events when they happen
• OnAnalogHigh
• OnAnalogLow
• OnAnalogChange
• OnAnalogNormal
• OnDiscreteChange

30. Alarming and Logging- VB Code
Setting up the watchpoint by
invoking the .WatchPointAdd
method in the PLC Comms
ActiveX Control
Use the .Autopoll method to start polling the
PLC when the command buttons are clicked
- also clear the alarms display when polling
starts
Build the high alarm
message text string,
display it in the list box,
then log the data to the
database using the data
controls methods

31. Alarming and Logging- VB Code
Build the low alarm
message text string,
display it in the list box,
then log the data to the
database using the data
controls methods

32. Alarming and Logging- VB Code
Build the normal alarm
message text string,
display it in the list box,
then log the data to the
Update a text box on the database using the data
screen each time a new controls methods
value is read from the
PLC
Do some simple data validation
when the user enters a PLC
memory address

33. Alarming and Logging -
Finished Product

34. Alarming and Logging -
Advanced Displays
For more advanced alarm
displays, ActiveX plug-
ins are available to
provide the needed
functionality

35. Recipe Loading - Setting up the
Data Control
Use VB’s standard
Data Control to
connect to a
database
• Don’t let all the properties confuse or
worry you
• Key properties to set on data control:
• DatabaseName = pathname and
filename of the database
• RecordSource = table name or
query name to get records from in
the database - data control gives
you a pull-down list

36. Recipe Loading - Data Binding
Text box properties page
has 2 key properties that
allow the user to connect
or “bind” the value shown
in the field to a column in
a database table or query
• DataSource - the name
of the data control that
you setup to connect to
the database
• DataField - the actual
column, pulled from an
auto-generated pulldown
Each text box field on the form is “bound” using the
list, whose data will be
DataSource and DataField properties to a column in
bound to the text box
the database

37. Recipe Loading - In Action
When the user clicks on the next
or previous recipe buttons, the
code shown below advances the
database pointer forward or
backward one record while
checking to make sure the
beginning or end of the database
table is not passed

38. Recipe Loading - In Action
When user clicks on “Download
to PLC”, the code below loads the
displays values into the PLC
ActiveX control and invokes its
trigger method to write the data to
the PLC. When the
OnWriteDone event fires, the user
is notified with a message box

39. Networking - Leveraging Newer
Ethernet Aware PLCs
Client PCs running your VB HMI Application and using a PLC ActiveX
control that supports direct Ethernet connections to the PLC
TCP/IP Ethernet Network
PLCs with built-in Ethernet Interfaces

40. Networking - Retrofitting to
Proprietary PLC Networks
Client PCs running your VB HMI Application and utilizing a PLC ActiveX control that provides with it an EXE
application for your server to bridge from Ethernet to the PLC networks or an ActiveX control that is an OPC client
and can talk to an OPC server
Remote user via
TCP/IP Ethernet Windows Dial-Up
Gateway Server running a software Network Networking
bridge between the PLCnetworks and
TCP/IP Ethernet
Proprietary PLC Network
• Provides a solution when the investment to replace PLCs with Ethernet Based CPUs is too high or the
PLC network interface cards for each client are cost-prohibitive
• The gateway software bridge can be either an EXE program that is included with some PLC
communications ActiveX controls or an OPC server

41. Transfer Line Application

42. Transfer Line Application

43. Microbrewery Application

44. Benefits of Using Visual Basic
for HMI Applications
• Use the right tool for the right job
– Simple to moderately complex apps
– Don’t reinvent a pre-configured HMI in VB if that’s
really what you need
• Support for wide range of ActiveX plug-ins
• Widely known scripting language
• Flexibility - you control the application
• Cost
– you can distribute your VB code royalty free
– ActiveX components have low or no royalty fees for

45. Resources for further learning
• Understanding ActiveX & OLE - David
Chappel, Microsoft Press
• Office97 Visual Programmers Guide -
Microsoft Press
• Microsoft Websites -
msdn.microsoft.com/vba
• Download copy of this presentation and
other presentations and technical papers at
www.softwaretoolbox.com/isaexpo98

46. Where do I find ActiveX controls and
tools for Industrial HMI Applications ?
Although this presentation is a non-commercial,
sharing of knowledge presentation, we added this
slide after show because so many of you at the show
were asking this question!
The Software Toolbox is a company that provides you
with a single place to look to find all the software tools
you need for automation applications, including Visual
Basic based HMI applications. Visit our website
today for more product information.
www.softwaretoolbox.com