EtherNet/IP basics in PLC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the standard EtherNet/IP port number.

PLC Programming

const EIP_PORT = [1];

Drag options to blanks, or click blank then click option'

A23

B502

C80

D44818

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 502 which is for Modbus TCP.

Using port 80 which is for HTTP.

Using port 23 which is for Telnet.

The standard port number for EtherNet/IP communication is 44818.

2fill in blank

medium

Complete the code to create an EtherNet/IP connection object with the IP address.

PLC Programming

let connection = new EIP.Connection('[1]');

Drag options to blanks, or click blank then click option'

A192.168.1.10

B255.255.255.0

C10.0.0.256

Dlocalhost

Attempts:

3 left

💡 Hint

Common Mistakes

Using subnet mask instead of IP address.

Using 'localhost' which is not valid for EtherNet/IP device connection.

Using invalid IP addresses.

The IP address must be valid and reachable. '192.168.1.10' is a typical private IP address.

3fill in blank

hard

Fix the error in the code to read a tag value from the PLC.

PLC Programming

connection.readTag('[1]').then(value => console.log(value));

Drag options to blanks, or click blank then click option'

A123Tag

BTag1

Ctag1

DTag-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase tag names when the PLC expects lowercase.

Using tag names with invalid characters like dashes.

Starting tag names with numbers.

Tag names are case-sensitive and usually lowercase or camelCase. 'tag1' is a valid tag name.

4fill in blank

hard

Fill both blanks to create a cyclic connection with a 500 ms interval and 1000 ms timeout.

PLC Programming

connection.createCyclicConnection({interval: [1], timeout: [2]);

Drag options to blanks, or click blank then click option'

A500

B1000

C300

D2000

Attempts:

3 left

💡 Hint

Common Mistakes

Setting timeout shorter than interval causing premature errors.

Using very low interval causing network overload.

Using very high timeout causing slow error detection.

The cyclic connection interval is 500 ms and the timeout is 1000 ms to allow for response delay.

5fill in blank

hard

Fill all three blanks to write a value of 100 to the tag 'MotorSpeed' with confirmation.

PLC Programming

connection.writeTag('[1]', [2]).then(response => { if(response.[3]) console.log('Write successful'); });

Drag options to blanks, or click blank then click option'

AMotorSpeed

B100

Csuccess

DSpeedMotor

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping tag name and value.

Using incorrect tag names.

Checking wrong response property.

The tag name is 'MotorSpeed', the value to write is 100, and the response property 'success' confirms the write.

Practice

1. What is the main purpose of EtherNet/IP in industrial automation?

easy

A. To provide wireless communication between devices

B. To allow machines to share data over Ethernet networks

C. To replace all PLC programming languages

D. To encrypt data for internet security

Solution

1. Step 1: Understand EtherNet/IP function

   EtherNet/IP is designed to connect industrial devices over Ethernet to share data.

2. Step 2: Compare options

   Only To allow machines to share data over Ethernet networks correctly describes this purpose; others describe unrelated functions.

3. Final Answer:

   To allow machines to share data over Ethernet networks -> Option B

4. Quick Check:

   EtherNet/IP = Data sharing over Ethernet [OK]

Hint: EtherNet/IP = Ethernet + Industrial Protocol for data sharing [OK]

Common Mistakes:

• Confusing EtherNet/IP with wireless protocols
• Thinking EtherNet/IP replaces programming languages
• Assuming it is for internet security encryption

2. Which of the following is the correct way to specify an IP address in EtherNet/IP communication?

easy

A. 192.168.1.1000

B. 192.168.1.256

C. 192.168.1

D. 192.168.1.100

Solution

1. Step 1: Recall valid IP address format

   An IP address has four numbers (octets) between 0 and 255 separated by dots.

2. Step 2: Check each option

   192.168.1.100 has valid numbers (192,168,1,100). Options B and D have numbers >255, and C has only three parts.

3. Final Answer:

   192.168.1.100 -> Option D

4. Quick Check:

   Valid IP = four numbers 0-255 [OK]

Hint: IP octets must be 0-255, four parts separated by dots [OK]

Common Mistakes:

• Using numbers greater than 255 in IP address
• Omitting one or more octets
• Using invalid characters or formats

3. Given the following PLC code snippet for reading a tag over EtherNet/IP:

ReadTag("192.168.0.10", "MotorSpeed")

What is the expected result if the tag MotorSpeed has a value of 1500?

medium

A. The function returns 1500

B. The function returns an error code

C. The function returns null

D. The function returns the IP address

Solution

1. Step 1: Understand ReadTag function

   ReadTag reads the value of a tag from a device at the given IP address.

2. Step 2: Check tag value

   The tag MotorSpeed has value 1500, so the function should return this value.

3. Final Answer:

   The function returns 1500 -> Option A

4. Quick Check:

   ReadTag returns tag value = 1500 [OK]

Hint: ReadTag returns the current tag value from device [OK]

Common Mistakes:

• Assuming it returns IP or error without reason
• Confusing tag name with value
• Expecting null if tag exists

4. You wrote this code to write a value to a tag over EtherNet/IP:

WriteTag("192.168.1.5", "PumpStatus", 1)

But the write fails. Which is the most likely cause?

medium

A. The tag name is misspelled or does not exist

B. The value 1 is not allowed for PumpStatus

C. The IP address is invalid

D. EtherNet/IP does not support writing values

Solution

1. Step 1: Check IP address validity

   192.168.1.5 is a valid IP address format, so unlikely the cause.

2. Step 2: Consider tag name correctness

   If the tag name is misspelled or missing, the write will fail.

3. Step 3: Evaluate value and protocol support

   Value 1 is usually valid for status tags; EtherNet/IP supports writing values.

4. Final Answer:

   The tag name is misspelled or does not exist -> Option A

5. Quick Check:

   Incorrect tag name causes write failure [OK]

Hint: Check tag spelling first if write fails [OK]

Common Mistakes:

• Assuming IP address is always wrong
• Thinking EtherNet/IP can't write data
• Ignoring tag name correctness

5. You want to monitor temperature from multiple devices using EtherNet/IP. Which approach best ensures efficient data collection?

hard

A. Poll each device individually in a loop with delays

B. Use a multicast message to request all devices at once

C. Configure a scanner to cyclically read tags from all devices

D. Manually connect to each device and read tags one by one

Solution

1. Step 1: Understand data collection methods

   Polling each device with delays or manual reads is slow and inefficient.

2. Step 2: Evaluate multicast and scanner options

   Multicast is not commonly used for EtherNet/IP tag reads; scanners efficiently cycle through devices automatically.

3. Final Answer:

   Configure a scanner to cyclically read tags from all devices -> Option C

4. Quick Check:

   Scanner cyclic reads = efficient multi-device monitoring [OK]

Hint: Use scanners for automatic cyclic data reads [OK]

Common Mistakes:

• Using manual or delayed polling causing slow updates
• Assuming multicast works for tag reads
• Not using built-in scanner features