The CAN analyzer I/O decodes analog data to CAN data.
The source of the analyzer can either be the differential CAN signal (preferred) or the CAN-high
signal.
The decoded fields can be shown in a Data grid sink.
The following fields are extracted from the CAN data by the analyzer:
| Field name | Purpose |
|---|---|
| Identifier (ID) | A (unique) identifier for the data |
| Remote transmission request (RTR) | If 1, remote data is requested |
| Identifier extension bit (IDE) | If 1, the ID consists of 29 instead of 11 bits |
| Reserved bit (R1) | Reserved bit, only in extended format |
| Reserved bit (R0) | Reserved bit (it must be set to dominant (0), but accepted as either dominant or recessive) |
| Data length code (DLC)* | Number of bytes of data (0-8 bytes) |
| Data | Transmitted data (length dictated by DLC field) |
| CRC | Cyclic Redundancy Check |
| CRC delimiter | Must be recessive (1) |
| Acknowledged | Indicates whether the message was acknowledged |
| ACK delimiter | Must be recessive (1) |
| Errors | Any errors detected in the message |
An example of analyzed CAN data is shown below.
Measurement on a CAN bus in a car, with decoded CAN data.
To control the behavior of the CAN analyzer I/O, several properties are available. These can be accessed through a popup menu which is shown when the I/O is right clicked.
For correct detection, the Bitrate property must be set to the correct value corresponding to the bus that is under measurement. It can be set to several common values, but also to a user defined value.
For signal edge detection, the CAN analyzer uses a level to which the signal is compared: all signal parts above this level are considered "high", all signal parts below this level are considered "low". The default value for the MidLevel property is 0.7 Volt.
You can change the displayed name of an object by giving it an Alias. This can be handy when you are dealing with a lot of objects and have problems keeping them apart. You can for example give channel one of your instrument the alias "Battery", when it is measuring a battery voltage. To give an object an alias, use the item Alias ... in its menu. To remove an alias and revert to the original name of the object, set the alias to an empty string.
When multiple sources or I/O's are displayed in a graph or a meter, they can be distinguished from each other by their Color. Three different color settings are available for a source or an I/O.
To disconnect all sources from an I/O or Sink at once, use the Disconnect all sources action.
To disconnect one or more sinks from an I/O or Source, use the Disconnect sink(s) action. This will show a dialog that lists all connected sinks. Individual sinks can then be selected and disconnected from the object.
To disconnect all sinks from an I/O or source at once, use the Disconnect all sinks action.
When a new object is to be created, similar to an already existing object, with the same properties, the Clone action can be used. This will create an identical copy of the original object, with the exact same properties. Source(s) and sink(s) of the new object are not yet connected.
The Delete action deletes a source, I/O or sink. All connections of the object will be disconnected and then the object will be removed from the object tree. The source property of the objects that used this object as source will be cleared. The sink property of the objects that used this object as sink will be cleared. An axis in a graph that was connected to this object will be also deleted.
The Export data action allows to export the data of an object to a file. This is detailed described on the page about Exporting data.
The Load action allows to load the settings and data for an object from a TPS or TPO file. This is detailed described on the page about Loading into selected objects.
The Save as action allows to save the settings and data of one or more objects to a TPO file. When multiple objects are selected, the connections between the objects are saved as well. This is detailed described on the page about Saving objects to a TPO file.