OPC (OLE for Process Control) in SCADA systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an OPC server connection.

SCADA systems

opc_server = OPCClient('[1]')

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A192.168.1.100

BOPCServer1

Clocalhost

DOPC_DA

Attempts:

3 left

💡 Hint

Common Mistakes

Using IP address instead of server name

Using generic terms like 'localhost'

The OPCClient needs the exact OPC server name to connect. 'OPCServer1' is the correct server name here.

2fill in blank

medium

Complete the code to read a tag value from the OPC server.

SCADA systems

value = opc_server.read('[1]')

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AOPCServer1

B192.168.1.100

CTag1

Dconnect

Attempts:

3 left

💡 Hint

Common Mistakes

Using server name or IP instead of tag name

Using method names instead of tag names

To read data, you specify the tag name. 'Tag1' is a valid tag identifier.

3fill in blank

hard

Fix the error in the code to write a value to an OPC tag.

SCADA systems

opc_server.write('[1]', 100)

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ATag1

Bconnect

Cwrite

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Using numeric values or method names as tag names

The first argument must be the tag name. 'Tag1' is correct to specify the tag to write to.

4fill in blank

hard

Fill both blanks to create a subscription and set the update rate.

SCADA systems

subscription = opc_server.create_subscription('[1]')
subscription.update_rate = [2]

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A1000

BTag1

C500

DTag2

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping tag name and update rate

Using tag names as update rate

The subscription is created for a tag name like 'Tag1'. The update rate is set in milliseconds, here 1000 ms.

5fill in blank

hard

Fill all three blanks to read multiple tags and store their values in a dictionary.

SCADA systems

tags = ['[1]', '[2]']
values = {tag: opc_server.read(tag) for tag in tags if tag [3] 'Tag1'}

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ATag1

BTag2

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '!=' in filter

Wrong tag names in list

The tags list includes 'Tag1' and 'Tag2'. The dictionary comprehension filters tags not equal to 'Tag1' using '!='.