CANopen PDO Example

Overview

This example shows Process Data Objects (PDOs) on a single CAN channel: one script transmits a TPDO when an object dictionary value changes, and the other receives that frame as an RPDO and prints the decoded mapping.

PDO traffic is low-overhead compared to SDO—suited for periodic or event-driven process data. Here both nodes attach to the same simulated CAN device (SIMULATE_0, 500 kbit/s) defined in canopen_pdo.ecb.

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Project layout

File	Role
canopen_pdo.ecb	ECUBUS project with two script nodes on one CAN device
pdo_producer.ts	CANopen device (node ID 0xB) with a TPDO on COB-ID 0x180, mapping 0x2000 (counter) + 0x2001 (motor speed, 0-100)
pdo_consumer.ts	Same node ID in a separate script instance with an RPDO on 0x180, mapping into 0x2000 + 0x2001

Each script wires the stack to the bus with Util.OnCan → device.receive(...) and forwards stack TX with device.addListener('message', ...) → output(...).

Producer (pdo_producer.ts)

1. Adds object 0x2000 (8-bit unsigned test value) and 0x2001 (motor speed, 0-100).
2. Declares a transmit PDO with transmissionType: 254 (send when mapped value changes), COB-ID 0x180, payload from 0x2000 + 0x2001.
3. Calls device.start() and device.nmt.startNode() so the device is operational.
4. Every 100 ms increments 0x2000 three times (1 -> 2 -> 3), which triggers TPDO sends.
5. Speed (0x2001) is controlled by panel variables:
   • MotorSpeedPlus: increment speed by 1 (clamped to 100)
   • MotorSpeedMinus: decrement speed by 1 (clamped to 0) Each change updates 0x2001 and triggers TPDO send-on-change.

Consumer (pdo_consumer.ts)

1. Adds 0x2000 and 0x2001 and a receive PDO on COB-ID 0x180 mapped to both objects.
2. After start() / startNode(), listens with device.pdo.on('pdo', ...) and logs COB-ID and each mapped object’s value.
3. When object 0x2001 is received, it writes the value to global variable MotorSpeed via setVar("MotorSpeed", value).

How to run

1. Open canopen_pdo.ecb in ECUBUS Pro.
2. Ensure both scripts (pdo_producer, pdo_consumer) use the same CAN channel (as in the bundled project).
3. Run the project; watch the consumer output for Received PDO lines with two mapped values (counter and speed).
4. Toggle MotorSpeedPlus / MotorSpeedMinus in the panel to change speed and observe synchronized PDO updates on the consumer side.

Further examples

The underlying stack follows common CANopen PDO patterns. For more standalone scenarios (NMT, SDO, SYNC, TIME, LSS, EMCY, etc.), see the node-canopen examples:

https://github.com/Daxbot/node-canopen/tree/main/examples