Harwa Limited · CANsignal Suite · Guides
SDO: ask for one object
A service data object is a request to a node. The SDO client in CANsignal Suite reads or writes an entry in the Object Dictionary while the project is connected. Use it for identity, a store command, or a parameter that changes rarely.
SDO traffic shows up in bus utilization as its own bucket, separate from PDO, EMCY, and heartbeat. If the bus looks busy, that split tells you whether the load is process data or parameter access.
PDO: the mapped values
A process data object is the frame the node sends or expects on a cycle or on an event. PDO mapping in the suite covers TPDO and RPDO, shows the bit budget, and can write the map when you are connected. Export DCF saves that map.
The PDO monitor shows the process data after the map is live. It is not the same view as Trace. Trace is every frame. The PDO monitor is the mapped values.
Which one to open
Open the SDO client when you need a single object. Open PDO mapping when you are deciding which objects ride in the cyclic frames. Open the PDO monitor when you want to see those frames’ values. Open the Object Dictionary when you need the name and the default from the EDS or DCF.
LSS is a third, narrower job: Fastscan, Configure Node-ID, Configure Bitrate, and Store. Use the LSS wizard when the node has no address yet. Do not use SDO for that. The current release is Classical CAN. A useful check after mapping is to clear Trace, start the node, and confirm the PDO monitor shows the mapped values changing while the SDO client stays idle. If the SDO client is busy during that check, something is still polling parameters, and the SDO share in bus utilization will show it.
Questions engineers ask
Can PDO mapping write to the node?
Yes, when the project is connected. The screen also shows the bit budget before you write, and it can export a DCF.
Does this guide assume CAN FD?
No. The current CANsignal Suite release is Classical CAN. CAN FD is planned and is not included.