CANopen Integration

Overview

Use this skill to debug CANopen by separating raw CAN bring-up, node identity, object dictionary, NMT state, SDO configuration, PDO mapping, heartbeat, and application semantics. CANopen cannot work reliably until raw CAN timing works.

When To Use

Use this skill when:

• The user is adding or debugging CANopen master/slave nodes, object

dictionaries, EDS/DCF files, PDOs, SDOs, NMT, heartbeat, SYNC, or EMCY.

• The issue involves missing PDOs, SDO aborts, node state, heartbeat timeout,

wrong COB-IDs, mapping errors, or network management.

• The implementation uses CANopenNode, a vendor stack, or a custom CANopen layer.

Do not use this skill for low-level CAN bit timing or transceiver bring-up. Use canbus-integration first when raw CAN frames are not proven.

First Questions

Ask for:

• CANopen stack, node ID, bitrate, raw CAN evidence, and network topology.
• Object dictionary entries, EDS/DCF, PDO mapping, COB-IDs, and NMT state.
• Master tool or peer node, SDO abort codes, heartbeat settings, and logs.
• Whether SYNC, TIME, EMCY, LSS, or boot-up messages are required.
• Exact frame capture from a CAN analyzer if available.

Debug Workflow

1. Prove raw CAN.

Confirm bitrate, sample point, transceiver, termination, and error counters.

1. Prove node identity.

Check node ID, boot-up message, NMT state, heartbeat producer/consumer, and expected COB-IDs.

1. Validate object dictionary.

Confirm index/subindex types, access rights, defaults, persistence, and application backing storage.

1. Debug SDO first.

Use SDO reads/writes to verify OD entries before enabling PDO mapping.

1. Debug PDO mapping.

Check mapping parameters, transmission type, inhibit/event timers, SYNC, and payload length.

1. Add safety behavior.

Handle heartbeat loss, EMCY, bus-off recovery, and safe outputs explicitly.

Common Failures

• Raw CAN works only at another bitrate or with missing termination.
• Node ID conflicts with another node or creates unexpected COB-IDs.
• OD type/access flags do not match the master expectation.
• PDO mapping is changed while the PDO is enabled.
• Heartbeat consumer timeout is shorter than realistic bus or boot timing.
• Application updates OD values without atomicity or endian consistency.

Verification

Before claiming CANopen works:

• State bitrate, node ID, stack, NMT state, and object dictionary source.
• Confirm boot-up, heartbeat, and SDO read/write of key OD entries.
• Confirm PDO mapping and timing with a CAN trace.
• Confirm heartbeat timeout, EMCY, or bus-off behavior if safety-related.

Example

User:

CANopen 主站读 SDO 返回 abort。

Agent:

1. Captures the abort code, index/subindex, node ID, and COB-ID.
2. Checks OD type, access rights, and backing variable.
3. Verifies raw CAN and NMT state before changing application logic.