Optimizing 1553 Bus Systems for Enhanced Robustness: Innovative Strategies by Sital Technology

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Optimizing 1553 Bus Systems for Enhanced Robustness: Innovative Strategies by Sital Technology

Current Scenario:

The conventional 1553 buses are constructed using a main bus structure with multiple stub connections and terminated with 78-ohm resistors at both ends. However, a major challenge arises when one of these termination resistors is damaged or disconnected. Unfortunately, existing market tools fail to identify this issue, resulting in a marginal signal-to-noise ratio that can still detect 1553 messages on the ground. However, during flight, noise levels escalate, leading to communication failures that are hard to diagnose during regular maintenance checks.

Common Challenges Faced:

Often, maintenance teams, facing communication breakdowns, have replaced multiple LRUs (Line Replaceable Units) in aircraft and platforms, only to find the issues persisting. This cycle of replacing components without addressing the root cause leads to continued communication breakdowns.

Our Innovative Solution:

To advance avionics systems maintenance, Sital Technology introduces an advanced diagnostic tool for effective identification of faults in the 1553 bus. This tool not only pinpoints faults related to termination resistors but also detects potential coupler failures, enhancing diagnostic capabilities significantly.

Learning from CAN BUS Technology:

A critical analysis of automotive systems using CAN BUS topology highlights a more effective strategy. In CAN BUS, termination resistors (120 ohms) are typically integrated within the edge Electronic Control Units (ECUs) at both ends of the bus. Consequently, whenever an ECU is replaced due to communication failures, the termination resistors are automatically replaced, ensuring continued robustness of the system.

Proposed Strategy for 1553 Buses:

Our proposed strategy, inspired by CAN BUS, involves modernizing 1553 bus systems with cutting-edge solutions to ensure enhanced communication reliability. Specifically, integrating the 78-ohm termination resistors inside the LRUs at both ends of the bus could drastically improve system resilience. Additionally, these terminating LRUs should adopt direct coupling rather than transformer coupling for enhanced efficiency.


Adopting this strategy, mirroring successful automotive industry practices, offers a reliable solution to strengthen 1553 bus systems. By addressing the inherent weaknesses in current bus topology, this proposal aims to mitigate communication failures and significantly improve maintenance efficiency. Embracing these changes will lead to a significant leap in avionics communication technology, benefiting the industry at large.

Contributed by

Ofer Hofman

Founder and CTO

Sital Technology.


Sital Technology, a leader in avionics communication solutions, is dedicated to innovating and improving aviation technology.

Troubleshooting The CAN Bus: Navigating Common Failure Scenarios

Troubleshooting The CAN Bus: Navigating Common Failure Scenarios

Like any technology, CAN Bus networks can encounter issues that require troubleshooting to maintain their reliability. In this comprehensive guide, we will explore common failure scenarios in CAN Bus systems and provide strategies for effective troubleshooting.

Understanding the CAN Bus Architecture

Before we dive into troubleshooting, it’s essential to have a basic understanding of the CAN Bus architecture:

  • Nodes: Nodes are the devices or components connected to the CAN Bus network. These can include sensors, controllers, and displays.
  • Messages: Information is transmitted in the form of messages on the CAN Bus. Each message has an identifier (ID) that determines its priority and content.
  • Termination: Proper termination with 120-ohm resistors at both ends of the network is crucial to prevent signal reflections and maintain data integrity.

Common Failure Scenarios and Troubleshooting Strategies

  1. Bus Off Error

Symptoms: The Bus Off error occurs when a node has transmitted too many messages in a short time or has encountered a severe fault. It results in the node being taken offline, causing a disruption in communication.

Troubleshooting Strategy:

  • Check the error logs to identify the specific node that triggered the Bus Off error.
  • Inspect the node for faults or issues that may have caused excessive message transmission.
  • Address any underlying problems with the node and reset it if necessary.
  • Monitor the network for stability after resolving the issue.
  1. Excessive Jitter or Delay

Symptoms: Excessive jitter or delay in message transmission can lead to unreliable communication and synchronization issues between nodes.

Troubleshooting Strategy:

  • Review the timing parameters and settings of all nodes in the network.
  • Ensure that nodes adhere to the specified bit rates and synchronization requirements.
  • Investigate the root cause of any jitter or delay, such as hardware or software issues.
  • Adjust node configurations or update software to minimize timing discrepancies.
  1. Message Collision

Symptoms: Message collisions occur when two or more nodes attempt to transmit messages simultaneously, resulting in corrupted data and communication disruptions.

Troubleshooting Strategy:

  • Analyze the message arbitration process to identify the nodes involved in collisions.
  • Verify that nodes are correctly configured with unique message IDs.
  • Adjust the message priorities and IDs to prevent collisions.
  • Consider implementing a collision resolution strategy, such as message queuing or prioritization.
  1. Signal Integrity Issues

Symptoms: Signal integrity issues manifest as distorted or noisy waveforms on the CAN Bus, leading to errors in message reception.

Troubleshooting Strategy:

  • Inspect the physical layer of the CAN Bus, including cables, connectors, and terminations.
  • Check for loose or damaged connections that may introduce signal noise.
  • Ensure that termination resistors are correctly placed and functioning.
  • Use an oscilloscope to analyze signal waveforms and identify sources of interference.
  • Shield cables or re-route them to minimize electromagnetic interference.
  1. Node Failures

Symptoms: Individual nodes may experience failures, leading to a loss of communication with that node and potential disruptions in system functionality.

Troubleshooting Strategy:

  • Isolate the malfunctioning node by disconnecting it from the network.
  • Perform a thorough inspection of the node for physical damage or component failures.
  • Check for software or firmware issues on the node’s microcontroller or controller area network interface.
  • Replace or repair the faulty node and ensure it is properly configured before reconnecting it to the network.
  • Monitor the network for stability after addressing the node failure.
  1. EMI and EMC Interference

Symptoms: Electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues can disrupt CAN Bus communication, leading to data corruption and errors.

Troubleshooting Strategy:

  • Evaluate the environment for potential sources of EMI, such as nearby high-voltage equipment or radio transmitters.
  • Shield the CAN Bus cables and connectors to reduce susceptibility to external interference.
  • Use twisted-pair cables and filters to minimize EMI effects.
  • Ensure that the CAN Bus network complies with EMC standards and regulations.
  • Conduct electromagnetic compatibility testing to validate the network’s immunity to interference.
  1. Software Bugs and Protocol Violations

Symptoms: Software bugs or protocol violations in node firmware or software can result in unexpected behavior and communication errors.

Troubleshooting Strategy:

  • Review the software code of the affected node for bugs or protocol violations.
  • Debug and correct the software to adhere to CAN Bus protocol standards.
  • Verify that the node’s firmware or software is up to date.
  • Test the corrected software in a controlled environment before deploying it in the network.
  1. Power Supply Issues

Symptoms: Inadequate or unstable power supplies can lead to voltage drops or spikes on the CAN Bus, affecting node operation.

Troubleshooting Strategy:

  • Verify that all nodes receive a stable and sufficient power supply within the specified voltage range.
  • Inspect power distribution circuits and connectors for loose connections or damaged components.
  • Implement voltage regulation and filtering to maintain a consistent power supply.
  • Monitor power quality and voltage levels during network operation to detect irregularities.

Troubleshooting the CAN Bus requires a systematic approach to identify and resolve common failure scenarios. By understanding the architecture of the CAN Bus network and employing effective troubleshooting strategies, you can maintain the reliability and performance of critical communication systems in industries ranging from automotive to industrial automation. Regular monitoring, testing, and preventive measures are essential for ensuring the seamless operation of CAN Bus networks.

CAN Bus Termination Testing: A Step-By-Step Guide

CAN Bus Termination Testing: A Step-By-Step Guide

The Controller Area Network (CAN Bus) is a widely used communication protocol in various industries, including automotive, aerospace, and industrial automation. For CAN Bus networks to function correctly, proper termination is essential. Termination testing helps ensure the network’s reliability and data integrity. In this comprehensive guide, we will walk you through the step-by-step process of CAN Bus termination testing, helping you maintain a robust and stable communication network.

Understanding CAN Bus Termination

Before delving into the testing process, let’s clarify the concept of termination in CAN Bus networks:

  • Impedance Matching

Termination in a CAN Bus network involves matching the network’s characteristic impedance with the impedance of the connected devices. The characteristic impedance of a CAN Bus is typically around 120 ohms. Proper termination ensures that signals do not reflect back into the network, preventing signal degradation and data errors.

  • Termination Resistor

Termination is achieved using a termination resistor, typically a 120-ohm resistor, placed at each end of the CAN Bus network. These resistors provide the correct impedance and absorb the signal energy at the ends of the network, preventing signal reflections.

Step-By-Step CAN Bus Termination Testing

Gather Necessary Tools and Equipment

To perform termination testing, you’ll need the following:

  • CAN Bus termination resistors (120 ohms)
  • A multimeter
  • A CAN Bus network
  • Appropriate connectors and cables

Identify the CAN Bus Network Ends

Determine the physical endpoints of your CAN Bus network. This might involve identifying the connectors or devices where the network terminates.

Disconnect the Terminating Resistors

Begin the testing process by disconnecting the termination resistors at both ends of the CAN Bus network. This step temporarily removes termination from the network.

Measure the Network’s Impedance

Using a multimeter set to measure resistance, check the impedance of the CAN Bus network without the termination resistors. Connect the multimeter probes to the ends of the network (where the termination resistors were previously connected) and record the measured impedance.

  • If the measured impedance is approximately 60 ohms, it indicates that the network is unterminated.
  • If the measured impedance is significantly different from 120 ohms, it suggests a potential issue with the network or the wiring.

Reconnect the Termination Resistors

Once you have measured the impedance without termination, reconnect the termination resistors at both ends of the CAN Bus network. Ensure that the resistors are securely connected.

Verify Termination

After reconnecting the termination resistors, recheck the impedance of the network using the multimeter. The impedance should now be approximately 120 ohms, indicating proper termination.

Inspect the Network for Errors

With the termination resistors in place, power up the CAN Bus network and monitor it for any error messages or communication issues. Error messages can indicate problems with the network’s termination or wiring.

Test Data Communication

To further validate the network’s performance, send test data through the CAN Bus and verify that it is transmitted and received correctly by the connected devices. Ensure that there are no data errors or issues with signal integrity.

Check Signal Waveforms

Use an oscilloscope to examine the CAN Bus signal waveforms. Properly terminated networks should exhibit clean, well-defined signal patterns without reflections or distortions. Any anomalies in the waveforms may indicate termination problems.

Document Test Results

Keep detailed records of your termination testing process, including impedance measurements, error messages, and oscilloscope waveform captures. This documentation can be valuable for troubleshooting and future reference.

Common Termination Issues and Solutions

During termination testing, you may encounter various issues that can affect the performance of your CAN Bus network. Here are some common problems and their solutions:

  • Incorrect Termination Resistance: If the measured impedance with termination resistors is not approximately 120 ohms, check the resistance values of the termination resistors themselves. Ensure they are indeed 120-ohm resistors and replace any faulty ones.
  • Wiring Problems: If the impedance measurements indicate significant deviations from 120 ohms, inspect the wiring for faults, such as open circuits, short circuits, or damaged cables. Repair or replace any faulty wiring.
  • Device Malfunctions: If the network still exhibits issues after proper termination, investigate the connected devices for malfunctions or incorrect settings. Verify that all devices are configured to use the same CAN Bus settings.
  • Signal Reflections: If signal waveforms on the oscilloscope show reflections or distortions, it may indicate impedance mismatches or cable faults. Check the quality of the cables and connectors and ensure that the characteristic impedance is maintained throughout the network.

Proper termination is crucial for the reliable operation of CAN Bus networks in various industries. By following this step-by-step guide for CAN Bus termination testing, you can ensure that your network’s impedance matches the required 120 ohms, preventing signal reflections and data errors. Regular termination testing is a proactive measure to maintain a robust and stable communication network, ensuring data integrity and system reliability.

CAN Bus 101: What It Is And How It Works

CAN Bus 101: What It Is And How It Works

The Controller Area Network (CAN Bus) is a fundamental communication protocol used in a wide range of industries, from automotive and manufacturing to aerospace and healthcare. In this article, we will delve into the world of CAN Bus, exploring its core concepts, how it operates, and its significance in modern systems.

The Controller Area Network, commonly referred to as CAN Bus, is a communication protocol used in electronic control systems. It was originally developed by Robert Bosch GmbH in the 1980s to address the growing need for efficient and reliable data exchange between electronic control units (ECUs) in automotive applications. Since then, it has expanded its reach to various industries where real-time communication is critical.

Understanding the Basics of CAN Bus

  • Message-Based Communication

CAN Bus is a message-based communication protocol, which means that devices or nodes on the network transmit messages to communicate with each other. These messages contain data and information necessary for the nodes to perform their functions.

  • Two-Wire Differential Signaling

CAN Bus operates using two-wire differential signaling, which consists of a CAN High (CANH) and a CAN Low (CANL) wire. This differential signaling helps in noise immunity, making CAN Bus suitable for use in electrically noisy environments.

How CAN Bus Works

  • Message Framing

In a CAN Bus network, messages are framed in a structure known as a “frame.” Each frame consists of a start-of-frame (SOF) bit, an arbitration ID (CAN identifier), control bits, data, a cyclic redundancy check (CRC), and an end-of-frame (EOF) bit. This structured approach ensures the integrity and reliability of data transmission.

  • Collision Resolution

CAN Bus uses a non-destructive arbitration method to manage data collisions. When two or more nodes attempt to transmit a message simultaneously, the node with the highest priority (lowest arbitration ID) gains bus access and transmits its message. This approach prevents data corruption and ensures a deterministic response time.

  • Broadcast Communication

CAN Bus supports broadcast communication, where a message sent by one node is received by all nodes on the network. While this might seem inefficient, it allows multiple nodes to react to the same message, making it suitable for applications that require synchronization or coordinated actions.

  • Error Handling

CAN Bus incorporates robust error detection and correction mechanisms. If an error is detected in a received message, the receiving node can request retransmission of the message. This redundancy and error-checking contribute to the protocol’s high reliability.

CAN Bus Variants

Over the years, several CAN Bus variants have emerged to meet specific industry requirements. Some of the notable variants include:

  • CAN 2.0A and CAN 2.0B: These are the two most common variants used in automotive applications. CAN 2.0A has an 11-bit identifier, while CAN 2.0B uses a 29-bit identifier, allowing for a more extensive range of unique message identifiers.
  • CAN FD (Flexible Data Rate): CAN FD extends the data rate and payload length, offering faster communication and increased flexibility. It is commonly used in applications where higher data transfer speeds are essential.
  • CANopen: CANopen is a higher-layer protocol that builds on the CAN Bus foundation. It provides standardized communication profiles and device profiles, simplifying the integration of devices from different manufacturers.

Applications of CAN Bus

CAN Bus finds applications in a wide array of industries:

  • Automotive: CAN Bus is the backbone of modern automotive electronics. It enables communication between various ECUs, including those responsible for engine control, transmission, braking, and entertainment systems.
  • Manufacturing and Industrial Automation: CAN Bus is used in industrial automation and robotics to connect sensors, actuators, and programmable logic controllers (PLCs). It facilitates real-time data exchange for precise control and monitoring.
  • Aerospace: CAN Bus is employed in aerospace systems, including avionics and flight control systems. It offers reliability and determinism for critical applications.
  • Healthcare: Medical devices often utilize CAN Bus for communication between sensors, monitors, and control systems, ensuring the timely and accurate transfer of patient data.
  • Marine and Off-Road Vehicles: CAN Bus is present in marine vessels and off-road vehicles, connecting navigation systems, engine controls, and safety systems.
  • Energy Management: In renewable energy systems and smart grids, CAN Bus helps monitor and control energy generation, storage, and distribution.

Challenges and Future Developments

While CAN Bus is a robust and reliable protocol, it does face challenges in meeting the demands of emerging technologies such as autonomous vehicles and Industry 4.0. These challenges have led to developments like CAN FD and CAN XL (CAN eXtra Large), designed to support higher data rates and larger payloads.

Additionally, cybersecurity concerns have prompted efforts to enhance the security of CAN Bus networks, as they are susceptible to malicious attacks due to their open nature.

The Controller Area Network (CAN Bus) is a foundational communication protocol that has revolutionized industries by providing a reliable and efficient means of data exchange. Its message-based communication, differential signaling, and robust error-handling mechanisms make it suitable for a wide range of applications, from automotive to aerospace and healthcare. As technology continues to advance, CAN Bus will evolve to meet the demands of modern systems while maintaining its core principles of reliability and determinism.

September 2023: We Are Part Of NASA’s Test Equipment!

We are part of NASA’s test equipment!

Sital Technologies will take an active part in the use of the equipment by testing 1553,

with the help of our component that has been with them since 2005, and by testers MCX.

To learn more click here:


An explanatory video on the NASA website:

An article on “Ynet” (Hebrew):


May 2023: IP Cores from Sital are now live on Lattice’s website!

We’re thrilled to announce that both IP Cores from Sital are now live on both websites!

At Lattice, we constantly strive to bring you the latest advancements and innovative solutions. With the addition of Sital’s IP Cores, we are expanding our offerings to provide you with even more cutting-edge capabilities for your projects.

Discover the exceptional features of these IP Cores by visiting our website today!

Click Here For More Info.
Also on Lattice's website.

For real-time updates, check out our LinkedIn page! Linkedin logo


May 2023: MIL-STD-1553 IP Cores

Exciting news from Sital Technology! 🚀

Looking for MIL-STD-1553 IP cores to meet your system requirements?

Look no further!

Sital Technology offers a wide selection of MIL-STD-1553 IP cores that are designed to accommodate diverse system needs.

Whether you’re using FPGAs or ASICs, our IP cores can be easily instantiated, providing you with flexibility and scalability.

And don’t miss out on our flagship BRM1553D-SnS core, packed with exceptional performance and Cyber security !

Click Here For More Info.

For real-time updates, check out our LinkedIn page! Linkedin logo

May 2023: MIL-STD-1553 BC Firewall

Sital Technology’s BC Firewall is now a standard feature in its BRM1553D IP core and other MIL-STD-1553 products, providing intrusion prevention and detection capabilities for unauthorized messages transmitted by rogue BCs.

The Firewall continuously monitors data buses and can detect any impersonating messages.
It also includes an option for intrusion protection, invalidating detected impersonating messages by crashing the bus during the transmission, preventing RTs from responding to such messages.

For more information go to our SnS News releases page !

For real-time updates, check out our LinkedIn page! Linkedin logo




February 2023: we celebrate 28 years!

28 years ago we started with lecturing on how to develop HDL HardWare to small groups of engineers in Israel…

While working, we realized the huge potential in our unique professional knowledge…! We then took it to the next level by developing our own data-bus protocols and products.
And now, even after 14 years of orbiting the moon, our Mil-Std-1553B is functioning with Zero resets inside NASA’s satellites !

From there, we continued with hard R&D work and drilled down to the physical layer signals of our data-bus protocols, and came up with 2 edge innovations:
1. Wiring fault detection: possible even on-flight and in super high resolution !
2. Data-bus cyber security: embedded HardWare protection against cyber attacks on both Automotive (CAN-bus) and Avionics (MIL-STD-1553) Industries !

SITAL Technology proud to provide worldwide the world’s most secure and advanced military standard databus products.
And looking forward, as always, to lead the industries to a “Safe & Secure” future…

For real-time updates, check out our LinkedIn page! Linkedin logo


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