DeviceNet Questions and Answers – Industrial Network Protocol
DeviceNet is a popular industrial networking protocol that enables communication between devices in a manufacturing environment. DeviceNet is based on the Controller Area Network (CAN) technology and provides a reliable and efficient means of connecting devices such as sensors, actuators, and other automation components. DeviceNet simplifies the installation and integration of devices, making it widely adopted in various industries for control, monitoring, and data exchange purposes.
Explore our top collection of DeviceNet Questions and Answers to understand the wide range of topics, including installation, configuration, troubleshooting, and integration. Enhance your knowledge of DeviceNet and harness its capabilities for seamless communication and efficient control in your industrial network.
What is DeviceNet?
DeviceNet is an industrial network protocol used in automation applications. It’s based on the Controller Area Network (CAN) protocol and is used for communication between devices like sensors, actuators, and complex devices such as programmable logic controllers (PLC).
Who developed DeviceNet?
DeviceNet was developed by Allen-Bradley, a company now owned by Rockwell Automation.
What are the primary components of a DeviceNet system?
The primary components of a DeviceNet system include devices (like sensors, actuators, and controllers), the communication cable, the power supply, and termination resistors.
What is the maximum data rate of DeviceNet?
DeviceNet supports three data rates: 125 Kbps, 250 Kbps, and 500 Kbps. The appropriate rate depends on the network’s physical size and the application requirements.
What is the maximum length of a DeviceNet network?
The maximum length of a DeviceNet network depends on the data rate. For 125 Kbps, the maximum length is 500 meters. For 250 Kbps, it’s 250 meters, and for 500 Kbps, it’s 100 meters.
How many nodes can be connected on a DeviceNet network?
A DeviceNet network can support up to 64 nodes.
What is the DeviceNet power supply voltage range?
The DeviceNet power supply voltage range is 11 to 25 volts DC.
How are devices addressed in a DeviceNet system?
Devices are addressed in a DeviceNet system by assigning them a unique node number from 0 to 63.
What types of data can be exchanged over DeviceNet?
DeviceNet can exchange various types of data including process data, configuration data, and diagnostic information.
Can DeviceNet support both cyclic and acyclic communication?
Yes, DeviceNet supports both cyclic (periodic) and acyclic (on-demand) communication.
What does a DeviceNet scanner do?
A DeviceNet scanner acts as a master on the network. It manages the communication between the devices (slaves), initiates cyclic I/O data exchanges, and processes acyclic messages.
What is the significance of the MAC ID in a DeviceNet system?
The MAC ID is a unique identifier assigned to each device on a DeviceNet system. It ranges from 0 to 63 and no two devices on the same network should have the same MAC ID.
What type of cable is used in a DeviceNet system?
A DeviceNet system typically uses a thick or thin round, shielded, 5-conductor cable. The cable includes two conductors for signal, two for power, and one for shield.
How is a DeviceNet network terminated?
A DeviceNet network should be terminated at both ends with a termination resistor to prevent signal reflections that could degrade network performance.
What is the role of EDS files in a DeviceNet network?
Electronic Data Sheet (EDS) files are used in a DeviceNet network to describe the features and capabilities of a device. They provide necessary information for configuration tools and help ensure the proper operation of devices.
Can DeviceNet be used in safety-critical applications?
Yes, there is a version of DeviceNet known as Safety DeviceNet which is designed for safety-critical applications. It includes features to ensure the integrity and reliability of safety-related data.
How does DeviceNet handle error detection and handling?
DeviceNet, being based on the CAN protocol, has robust error detection and handling features. It uses mechanisms such as checksums, acknowledgment bits, frame monitoring, and fault confinement.
What is Group 2 only server in DeviceNet?
A Group 2-only server is a device in DeviceNet that only responds to explicit messages and cannot initiate communication.
What is a DeviceNet Adapter?
A DeviceNet adapter is a device that communicates with a scanner. The scanner reads and writes I/O data from and to the adapter.
What is a DeviceNet gateway?
A DeviceNet gateway is a device that acts as a bridge between DeviceNet and another network protocol. It translates messages between the two protocols, enabling communication between devices on different networks.
What are the typical applications of DeviceNet?
DeviceNet is widely used in various industries such as automotive, packaging, food and beverage, and material handling. It is typically used for device-level communication between sensors, actuators, and controllers.
What is the difference between a ‘thick’ and ‘thin’ DeviceNet cable?
The difference lies primarily in their physical dimensions and the current carrying capacity. Thick cables are physically larger, can carry more current, and are typically used for trunk lines. Thin cables are smaller and are usually used for drop lines.
How is DeviceNet power supply different from regular DC power supply?
DeviceNet power supplies are designed to withstand the harsh environments often found in industrial settings. They usually provide power within the 11 to 25 volts DC range required for DeviceNet and are short-circuit protected.
Can you mix different data rates on the same DeviceNet network?
No, all devices on a DeviceNet network must communicate at the same data rate. The data rate is determined by network configuration and is typically set by the scanner.
What are the three types of messages in DeviceNet?
The three types of messages in DeviceNet are I/O messages (for periodic data exchange), Explicit messages (for device configuration and data parameter querying), and Network management messages (for managing devices and network operation).
How does DeviceNet ensure data consistency?
DeviceNet uses the Producer/Consumer model to ensure data consistency. In this model, one device (the producer) produces data that can be consumed by multiple other devices (the consumers). This ensures that all devices have a consistent view of the data.
What is the role of a DeviceNet repeater?
A DeviceNet repeater is used to extend the length of a DeviceNet network beyond the maximum allowed length or to increase the number of nodes beyond the maximum allowed. It does this by regenerating and retransmitting the signal.
What happens if two devices on a DeviceNet network have the same MAC ID?
If two devices on a DeviceNet network have the same MAC ID, it will result in a communication conflict. Both devices will try to communicate using the same address, causing errors. This is why each device on a network must have a unique MAC ID.
What is the significance of the baud rate in DeviceNet?
The baud rate in DeviceNet refers to the speed at which data is transmitted over the network. It affects the maximum length of the network and the amount of data that can be transmitted in a given time.
Can DeviceNet communication be monitored or diagnosed?
Yes, DeviceNet communication can be monitored and diagnosed using various tools, such as network analyzers, PC-based software tools, or built-in diagnostic features in the devices themselves.
What are the advantages of using DeviceNet?
Some advantages of DeviceNet include simplified wiring, robustness to noise, flexible topology, the ability to transmit power and data over the same cable, and support for a large number of nodes.
What protocol does DeviceNet use for transport and network layers?
DeviceNet uses the Common Industrial Protocol (CIP) for its transport and network layers. This allows it to offer services like explicit messaging and I/O messaging.
How is DeviceNet different from Ethernet/IP?
While both DeviceNet and Ethernet/IP uses the Common Industrial Protocol (CIP), they differ in their physical layers and some parts of their data link layers. DeviceNet is based on the CAN bus and is used for lower-level device communication, while Ethernet/IP uses Ethernet and is used for higher-level device and systems integration.
How can a DeviceNet system be protected from overvoltage or transients?
Overvoltage and transients can be mitigated using surge protection devices. These devices, when installed properly, can limit the voltage on the DeviceNet network to safe levels.
What is a DeviceNet scanner module?
A DeviceNet scanner module is a hardware module that can be installed in a PLC or other controller. It allows the controller to manage DeviceNet communication, acting as a master on the network.
Can you connect a PC to a DeviceNet network?
Yes, you can connect a PC to a DeviceNet network using a PC interface card or a USB-to-DeviceNet adapter. This allows the PC to monitor, diagnose, or manage the DeviceNet network.
What happens if a DeviceNet termination resistor is missing?
If a termination resistor is missing, it can lead to signal reflections on the network. These reflections can cause communication errors or even a complete loss of communication.
Can you use a regular Ethernet cable for a DeviceNet network?
No, regular Ethernet cable should not be used for a DeviceNet network. DeviceNet requires a specific type of cable that can carry both power and data.
What is meant by ‘drop line’ in a DeviceNet network?
A ‘drop line’ in a DeviceNet network is a cable that connects a device to the trunk line. Drop lines are typically shorter and use thinner cable than the trunk line.
What tools can you use to design a DeviceNet network?
There are various network design tools available from different manufacturers that can help with designing a DeviceNet network. These tools can assist with calculating power requirements, checking network load, selecting appropriate devices and cables, and overall network layout.
How do you identify a problem in a DeviceNet system?
Problems in a DeviceNet system can be identified through diagnostic tools, looking for signs such as blinking LED indicators on devices, checking error codes, or using network analyzing software.
Can you connect a USB device to a DeviceNet network?
Directly connecting a USB device to a DeviceNet network isn’t possible. However, there are USB-to-DeviceNet adapters available that can enable a PC with a USB interface to communicate with the DeviceNet network.
How can you extend the length of a DeviceNet network?
To extend the length of a DeviceNet network beyond its maximum allowable length, repeaters can be used. They regenerate the signal and allow for longer cable distances.
What does the DeviceNet specification define?
The DeviceNet specification defines the physical and data-link layers of the network based on the CAN protocol. It also includes definitions for the transport, session, and application layers based on the Common Industrial Protocol (CIP).
How can you configure a DeviceNet device?
DeviceNet devices can be configured using various software tools, typically provided by the device manufacturer. These tools allow the setting of parameters like the MAC ID and the baud rate.
Can DeviceNet support peer-to-peer communication?
Yes, DeviceNet can support peer-to-peer communication. This allows any device on the network to communicate directly with any other device, assuming the devices support this communication model.
What happens when a DeviceNet device fails?
When a DeviceNet device fails, it can disrupt network communication. The network master (scanner) can detect the failure and notify the control system, which can then take appropriate action.
What is the power consumption of a typical DeviceNet device?
The power consumption of a DeviceNet device can vary greatly depending on the type and model of the device. However, most devices use only a small amount of power, typically a few hundred milliamps at most.
Can you use DeviceNet in a hazardous location?
Yes, DeviceNet can be used in a hazardous location provided the devices and installation methods are rated and approved for such use. This typically involves using intrinsically safe barriers or isolators and devices rated for hazardous locations. Always follow local codes and regulations when installing network equipment in hazardous locations.
Can you use DeviceNet with other Fieldbus protocols in a hybrid network?
Yes, gateways or bridges can be used to connect a DeviceNet network to networks running other Fieldbus protocols, enabling data exchange between the networks.
What is a “DeviceNet card”?
A DeviceNet card is a hardware component that can be installed in a computer or industrial device to enable communication with a DeviceNet network.
Are there any industry-specific versions of DeviceNet?
Yes, there are variants of DeviceNet designed for specific industries, like Marine DeviceNet and Safety DeviceNet.
What measures does DeviceNet use for error detection?
DeviceNet uses several mechanisms inherited from the CAN protocol for error detection, including frame checking, acknowledgment check, and cyclic redundancy check (CRC).
Can DeviceNet be used for motion control applications?
Yes, DeviceNet can be used for simple motion control applications, but for more complex or high-speed requirements, a dedicated motion control network may be more suitable.
Can you use fiber optic cable for DeviceNet?
Yes, you can use fiber optic cables with DeviceNet, but you will need to use media converters to convert the electrical signals from the DeviceNet devices to optical signals, and vice versa.
What is a “DeviceNet star topology”?
A DeviceNet star topology is a network configuration where each device is connected directly to a central point, such as a hub or a switch. However, this topology is not typically recommended for DeviceNet due to the increased potential for reflection issues.
How does DeviceNet handle network arbitration?
DeviceNet, like CAN, uses non-destructive bitwise arbitration. When two messages are transmitted at the same time, the message with the higher priority (i.e., the lower arbitration ID) automatically gets transmitted first without any loss of data.
What are some typical causes of network faults in a DeviceNet system?
Network faults in a DeviceNet system can be caused by various factors such as incorrect wiring, duplicate MAC IDs, device failure, lack of termination, and electromagnetic interference.
Can you run DeviceNet and power wires in the same conduit?
It’s generally not recommended to run DeviceNet and high-voltage power wires in the same conduit due to the risk of noise interference. Always follow local codes and regulations concerning cable installation.
What is a “DeviceNet EDS file”?
An Electronic Data Sheet (EDS) file is a text file used in DeviceNet that describes the features of a device. It is used by configuration software to identify the device and to display its configurable parameters.
Can I use DeviceNet in high-temperature environments?
DeviceNet can be used in high-temperature environments if the devices and cables used are rated for those temperatures. Always consult the specifications provided by the manufacturer.
Is it possible to create a wireless DeviceNet network?
It’s technically possible to create a wireless bridge between two parts of a DeviceNet network using industrial wireless technology. However, this is not a common practice and can introduce additional complexity and potential issues.
How do you select the right power supply for a DeviceNet network?
The power supply for a DeviceNet network should provide voltage within the range of 11-25 VDC, be capable of supplying enough current for all devices on the network, and ideally be short-circuit protected.
What is the process to add a new device to a DeviceNet network?
To add a new device to a DeviceNet network, you need to physically install the device, connect it to the network, set its MAC ID and baud rate (if not already set), and then configure it using the network’s configuration tool.
How can you replace a failed device in a DeviceNet network?
To replace a failed device, you would remove the old device, install the new one, set its MAC ID to match the old device, and then configure it as needed. The network configuration tool should recognize the new device as a replacement for the old one.
How can you secure a DeviceNet network?
Security measures for a DeviceNet network can include physical security of devices and network connections, network segmentation, and controlling access to the network configuration and management tools.
What is “DeviceNet Safety”?
DeviceNet Safety is a protocol based on standard DeviceNet but with additional features for safety-related communication. It is used in safety-critical applications to ensure reliable and fail-safe communication.
Can you use different brands of devices on the same DeviceNet network?
Yes, as long as each device adheres to the DeviceNet standard, devices from different manufacturers can coexist on the same network.
How do you troubleshoot a DeviceNet network with intermittent communication problems?
Intermittent problems can be tricky to diagnose. Possible steps include checking for loose or damaged connections, monitoring the network for electromagnetic interference, checking power supply stability, and using a network analyzer tool to identify any problematic patterns.
What factors affect the maximum length of a DeviceNet network?
The maximum length of a DeviceNet network is affected by factors such as the baud rate, the type of cable used, and the number of devices connected.
Can DeviceNet networks be used in mobile applications?
Yes, DeviceNet networks can be used in mobile applications such as in vehicles or portable equipment, thanks to their robust physical layer based on the CAN bus.
How does DeviceNet ensure data consistency in the network?
DeviceNet uses the Producer/Consumer model to ensure data consistency. A device producing data (Producer) will send it out on the network, and any device that needs that data (Consumer) can use it. This ensures all consumers have the same, consistent data.
How is DeviceNet grounded?
DeviceNet should be grounded at one point in the network to prevent ground loops. It’s typically grounded at the power supply.
Can you monitor the data on a DeviceNet network?
Yes, you can monitor the data on a DeviceNet network using various tools such as a network analyzer, a DeviceNet monitoring software, or a PLC with a DeviceNet interface.
What is DeviceNet QuickConnect?
QuickConnect is a feature in DeviceNet that allows devices to be quickly swapped or replaced on the network with minimal disruption to the network communication.
Can you power a DeviceNet network using PoE (Power over Ethernet)?
No, PoE is a different technology and is not compatible with DeviceNet. DeviceNet power is typically supplied via the same cable used for data, but it requires a separate power supply.
How can you isolate sections of a DeviceNet network?
Isolation of sections of a DeviceNet network can be achieved using repeaters or network isolators. This can help in troubleshooting, in preventing faults from propagating, or in creating separate voltage zones.
How can you perform a loopback test on a DeviceNet network?
A loopback test on a DeviceNet network can be performed using a device that supports this function. The device sends a message to itself through the network, helping to verify the network’s functionality.
What type of network is DeviceNet?
DeviceNet is a digital, multi-drop network that connects industrial devices like sensors and actuators to PLCs and other industrial controllers.
What protocol does DeviceNet use?
DeviceNet uses the Common Industrial Protocol (CIP) over Controller Area Network (CAN).
Why is DeviceNet considered a ‘deterministic’ network?
DeviceNet is considered deterministic because it provides consistent and predictable (i.e., deterministic) data transfer times. This is essential for real-time control in industrial applications.
How does DeviceNet handle collisions on the network?
DeviceNet uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) to manage network access. With this protocol, devices check to see if the network is busy before transmitting, reducing the likelihood of collisions.
How does DeviceNet handle device addressing?
Each device on a DeviceNet network is assigned a unique MAC ID (0-63), which is used for addressing the device on the network.
What is the purpose of the DeviceNet terminator?
The terminator is used at the ends of the DeviceNet network to match the impedance of the cable and reduce reflections of the signal, improving network reliability and performance.
What types of devices can be connected to a DeviceNet network?
DeviceNet can connect a wide range of industrial devices, including sensors, actuators, motor controllers, safety devices, I/O modules, PLCs, and more.
What is the physical layer of DeviceNet based on?
The physical layer of DeviceNet is based on the CAN (Controller Area Network) standard, which defines things like cable types, connectors, and electrical signal levels.
What is the baud rate range for DeviceNet?
DeviceNet supports three baud rates: 125 kbps, 250 kbps, and 500 kbps. The actual rate used depends on the network configuration and the distance data needs to travel.
What is the significance of MAC IDs in DeviceNet?
A MAC ID is a unique identifier assigned to each device on a DeviceNet network. It allows the network master to address each device individually.
How is power distributed in a DeviceNet network?
Power is typically distributed through the same trunk cable that carries the data signal. Two of the five conductors in the cable are used for power.
What is the primary function of a DeviceNet master?
The primary function of a DeviceNet master, often a PLC, is to control the data flow on the network, including initiating communications and managing the network schedule.
What does “trunk-line/drop-line topology” mean in the context of DeviceNet?
In a trunk-line/drop-line topology, the main communication cable (trunk line) runs through the network, and individual devices connect to it via shorter cables (drop lines).
Is there any limit to the length of the drop line in DeviceNet?
Yes, the maximum length of a drop line in DeviceNet depends on the baud rate. For 125 kbps, it can be up to 6 meters; for 250 kbps, up to 3 meters; and for 500 kbps, up to 1 meter.
How is DeviceNet different from Ethernet/IP?
While both DeviceNet and Ethernet/IP use the Common Industrial Protocol (CIP), they differ in their physical layers, with DeviceNet using CAN and Ethernet/IP using Ethernet. They also differ in their speed, distance capabilities, and network infrastructure.
What is meant by “DeviceNet node commissioning”?
DeviceNet node commissioning is the process of adding and setting up a new node on the network, including physical installation, addressing (MAC ID assignment), and configuration.
What kind of connector is typically used for DeviceNet?
DeviceNet typically uses a 5-pin circular connector, often referred to as a mini-style or micro-style connector. The connector follows the specifications outlined in the DeviceNet standard.
What is the meaning of ‘DeviceNet conformance testing’?
DeviceNet conformance testing is a process to ensure a device complies with the DeviceNet standard and will work correctly on a DeviceNet network. It is typically performed by a third-party testing lab.
What is the ‘Group 2 only’ mode in DeviceNet?
‘Group 2 only’ mode is a configuration for DeviceNet devices that only need to support the Group 2 (poll/response) communication mechanism and not the more complex Group 1 (I/O) mechanism.
What is the maximum current capacity for a DeviceNet network?
The maximum current capacity for a DeviceNet network is typically 8 Amps for the trunk line, though this can depend on factors such as cable length and diameter.
How can you prevent a single device failure from affecting the whole DeviceNet network?
Proper network design, including the isolation of network segments, can prevent a single device failure from affecting the whole network. Also, using devices with built-in short-circuit protection can prevent a single device short-circuits from bringing down the network.
What is the purpose of the ‘DeviceNet traffic analyzer’?
A DeviceNet traffic analyzer is a tool used to monitor and diagnose the network. It can capture and decode network traffic, helping to troubleshoot issues and optimize network performance.
What is meant by ‘DeviceNet error codes’?
DeviceNet error codes are codes returned by devices when they encounter an error. They can provide useful information for diagnosing and fixing issues on the network.