One of the questions that recently crossed my mind was whether our existing SAE J1939 gateways and monitoring tools could be useful in the agricultural sector, specifically for monitoring ISOBUS networks.
The short answer appears to be:
Yes, in many cases they can.
The longer answer is a bit more nuanced.
Why the Question Matters
For many years, our products have focused on SAE J1939 applications in trucks, buses, construction equipment, power generation systems, and industrial machinery. During that time, we have developed a range of CAN bus gateways, protocol converters, simulators, and monitoring tools designed specifically for J1939 networks.
Recently, I began wondering whether these same tools could also serve engineers working with agricultural equipment.
After all, modern tractors, seeders, sprayers, balers, and implements are increasingly dependent on electronic communication networks. The dominant networking standard in that world is ISOBUS, formally known as ISO 11783.
And that is where things become interesting.
ISOBUS and J1939: Close Relatives
Engineers familiar with SAE J1939 quickly notice many similarities when they first encounter ISOBUS.
Both systems use:
- CAN bus technology
- 29-bit extended CAN identifiers
- Parameter Group Numbers (PGNs)
- Address claiming
- Transport Protocol messages
- Broadcast communication
In fact, ISOBUS was largely derived from SAE J1939.
This means that, from a network perspective, much of the traffic looks surprisingly familiar to anyone who has worked with heavy-duty vehicle networks.
Can a J1939 Gateway Connect to an ISOBUS Network?
From a hardware perspective, the answer is generally yes.
Most ISOBUS networks operate at 250 kbps, which is also the standard data rate used by SAE J1939 networks.
As long as a gateway supports:
- CAN 2.0B communication
- Extended 29-bit identifiers
- 250 kbps operation
it should be able to receive and transmit ISOBUS traffic.
That means many existing J1939 interfaces can physically connect to an ISOBUS network and observe the traffic.
Of course, proper cabling and connector adaptation may be required, but the underlying CAN communication itself is largely compatible.
What About J1939 Monitoring Software?
This is where expectations need to be managed.
Our JCOM1939 Monitor, for example, displays CAN messages and extracts information such as:
- PGN
- Source Address
- Destination Address
- Message frequency
- Transport Protocol activity
- Address Claim messages
These functions are useful regardless of whether the network belongs to a truck, a generator, or a tractor.
However, there is one important limitation.
The current version of JCOM1939 Monitor does not contain an ISOBUS database.
In other words, the software can identify the PGN number, but it does not necessarily know what that PGN represents within the ISOBUS environment.
For example, the software may display:
| PGN |
|---|
| 65096 |
| 65098 |
| 65110 |
but it will not automatically translate those numbers into human-readable agricultural functions.
Is That a Problem?
It depends on what you are trying to accomplish.
Many troubleshooting tasks do not require detailed parameter decoding.
Engineers often need answers to questions such as:
- Which nodes are active on the network?
- Are devices claiming addresses correctly?
- What messages are being transmitted?
- How frequently are they transmitted?
- Is Transport Protocol functioning properly?
- Is the network overloaded?
- Are messages missing?
For these tasks, seeing the PGN number alone is often sufficient.
In fact, many network investigations begin with exactly this type of traffic analysis before anyone starts interpreting the actual application data.
Possible Future Enhancements
As I explored the idea further, I realized that supporting ISOBUS may not require a complete redesign of existing tools.
One possible enhancement would be a user-loadable database that associates PGNs with descriptive names.
Instead of displaying:
| PGN |
| 65096 |
the monitor could display:
| PGN | Description |
| 65096 | Tractor ECU Status |
or whatever description is defined in the database.
Such an approach could potentially support:
- SAE J1939
- ISOBUS
- NMEA 2000
- Proprietary CAN networks
using the same monitoring platform.
At this point, however, this remains an idea rather than a planned feature.
The Reality: We Are New to Agriculture
This brings me to an important point.
While we have decades of experience with SAE J1939 and CAN networking, we do not currently have hands-on experience with agricultural ISOBUS applications.
That means we are approaching this topic from the perspective of CAN and J1939 engineers who are evaluating a potentially interesting new market.
As a result, there are undoubtedly aspects of ISOBUS implementation, diagnostics, certification, and real-world field usage that we have not yet encountered.
We’d Like Your Feedback
This is where I would greatly appreciate input from engineers, technicians, equipment manufacturers, system integrators, and researchers working in the agricultural sector.
If you work with ISOBUS systems, I would be interested in hearing:
- Do you currently use CAN monitoring tools for ISOBUS troubleshooting?
- Would a J1939-based monitoring tool be useful for your work?
- What information do you most frequently need when analyzing ISOBUS traffic?
- Do you require full parameter decoding, or is PGN-level analysis sufficient for many tasks?
- What features are missing from current ISOBUS diagnostic tools?
Most importantly:
Have you successfully used standard J1939 tools on ISOBUS networks?
If so, I would love to hear about your experiences.
The agricultural industry continues to adopt increasingly sophisticated electronic systems, and understanding how existing J1939 technologies fit into that environment could open interesting opportunities for both developers and users alike.
As always, I welcome your comments and feedback.
SAE J1939 Starter Kit and Network Simulator
Our JCOM.J1939 Starter Kit and Network Simulator is designed to allow the experienced engineer and the beginner to experiment with SAE J1939 data communication without the need to connect to a real-world J1939 network, i.e., a diesel engine. It may sound obvious, but you need at least two nodes to establish a network. That fact applies especially to CAN/J1939, where the CAN controller shuts down after transmitting data without receiving a response. Therefore, our jCOM.J1939 Starter Kit and Network Simulator consists of two J1939 nodes, namely our jCOM.J1939.USB, an SAE J1939 ECU Simulator Board with USB Port.
The jCOM.J1939.USB gateway board is a high-performance, low-latency vehicle network adapter for SAE J1939 applications. The board supports the full SAE J1939 protocol according to J1939/81 Network Management (Address Claiming) and J1939/21 Transport Protocol (TP). More Information…
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