CANopen Network Interface
Process Data Object (PDO) Transmission
Definition of PDO PDOs are objects which provide the communication interface with process data and enable them to be exchanged in real time. A CANopen device's PDO set describes the implicit exchanges between this device and its communication partners on the network.
The exchange of PDOs is authorized when the device is in "Operational" mode.
Types of PDO There are two types of PDO:
PDOs transmitted by the device ("Transmit PDO", "TPDO")
PDOs received by the device ("Receive PDO", "RPDO")
PDO Consumer/ PDOs are based on the "Producer / consumer" model ("Producer" / "Consumer").
Producer The device which sends out a PDO is called the producer, while the device receiving it is known as the consumer.
PDO |
| In addition to data to be transported, it is possible to configure the type of exchange | |||||
Transmission | for each PDO. |
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Modes |
| The PDO transmission mode can be configured as described in the table below. | |||||
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Transfer code | Transmission mode |
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Dec. | Hex. | Cyclic | Acyclic | Synchron | Asynchro | only RTR |
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| ous | nous |
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0 | 0 |
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| Send PDO on first SYNC |
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| message following an |
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| event |
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1 to 240 | 1 to F0 | x |
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| Send PDO every x SYNC |
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| messages |
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241 to 251 | F1 to FB | Reserved |
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252 | FC |
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| x | Receive SYNC message |
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| and send PDO on |
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| Remote Request |
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253 | FD |
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| x | x | Update data and send |
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| PDO on Remote Request |
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254 to 255 | FE to FF |
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| Send PDO on event |
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| (Change of state mode) |
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56 | 1606218 02 08/2006 |
