The decision depends on both devices, electrical conditions and the operating environment. Communication on a development board alone is insufficient to justify removing isolation. Two CAN ports or independent networks do not automatically provide galvanic isolation. Review signal paths, power paths and any ground connection that crosses the intended barrier.
Selection Checklist
| Condition | Information or Measurement Needed | Selection Impact |
|---|---|---|
| Ground relationships | Reference grounds, chassis ground, supplies and connections | Ground potential differences and return paths |
| Component capability | Transceiver common-mode range, ratings and isolator documentation | Whether operating conditions stay within specified limits |
| Isolation boundary | Signal isolation, isolated power, debug ports and other connections | Possible bridging or bypass of the intended barrier |
| Site conditions | Cable, termination, interference sources, ESD and surge requirements | Protection, layout, connectors and test scope |
| Product conditions | Installation, temperature, enclosure, maintenance and applicable requirements | Development board, board revision or custom product hardware |
Assess Prototype and Product Conditions Separately
Short communication on a controlled bench demonstrates the tested interaction under those conditions. It does not establish field immunity, safety or long-term operation. Record prototype connections and limits first. Product development then assesses isolated power, interface protection, layout, harness and tests for the intended environment. Hardware changes should follow documented findings.
Which Evidence Is Not Interchangeable?
An isolated transceiver does not establish system safety certification. A dual CAN label does not prove isolation on both channels. Separate CAN buses do not rule out a shared ground path. Isolation ratings in a chip datasheet must not be presented as the result of a whole-product withstand test.
Reference and Project Assessment
TI discusses ground potential differences and electromagnetic compatibility as considerations for isolated CAN in industrial interfaces. The reference identifies assessment factors; isolation ratings, protection parameters and pass criteria still depend on project equipment and design. Without schematics and device conditions, the assessment remains unverified.
References
Questions and Answers
Do two separately connected CAN buses establish galvanic isolation?
No. Independent controllers and communication paths let the two buses be handled separately. Galvanic isolation also requires a review of the transceivers, power, grounding and other connection paths. Two ports or two message-processing paths do not establish isolation.
Does bench communication validate a non-isolated development board for field use?
The bench result covers the grounding, power, cables and interference conditions used. Field use still requires a review of the actual environment, potential differences, interface protection and equipment requirements, followed by project-specific verification. Passing prototype communication does not replace product-interface validation.
What hardware information is needed to assess an isolation approach?
Provide the board schematic and revision, CAN controller and transceiver details, power and grounding paths, connector pinouts, cables and termination, interface protection and expected environment. Review the complete connection against both devices. A component description or architecture diagram alone is not a system isolation test record.
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