Editing database channel parameters
NOTE
The current offering is for advanced users who understand CAN sufficiently to generate a valid CAN database file. Channel parameters currently have limited validations.
NOTE
Edited CAN databases can be exported in a simplified Vector CAN DBC file format. This is provided primarily for portability from one eDAQXR, eDAQXR-lite or CX23-R device to another. The exported DBC file is not guaranteed to be usable by Vector applications (e.g., CANalyzer, CANape, etc.). The user interface does not validate all user edits that can result in the Vector applications rejecting the exported DBC file. For example, in Vector applications, a Signal or Message name is only valid using letters, numbers and underscores (_).
Database channel content may be edited using the spreadsheet grid cells, or by using the Single channel editor dialog window invoked by clicking on the Edit button in the task pane.
Single channel editor for CAN database channels
Right click on a channel and select Edit from the dropdown menu.
A dialog shows editable parameters.
- Name: Typically, this is the Channel name and also the Vector CAN DBC file Signal name. However, if the database was imported using the option to prepend the Message name to the Signal name using a delimiter, channels that are edited (or added) must conform to this name format. To be compatible with Vector applications, use only letters, numbers and underscores (_).
- Message ID: Enter a valid value in hexadecimal format limited to 29 bit significance.
- Description: There are no restrictions on user input for this.
- Message name: This must be consistent across all channels that have the same Message ID. To be compatible with Vector applications, use only letters, numbers and underscores (_).
- Message ID: Enter a valid value in hexadecimal format limited to 29 bit significance. The user interface provides limited validations on this value.
- Mask: Use FFFFFFFF by default. For advanced users, enter an appropriate value in hexadecimal format in the range of 0 to FFFFFFFF. See CAN channels > Technical Note: CAN Message ID Masking for more information.
- Bit start, Bit length: The user must provide valid values. Basic validations are performed (e.g., the sum of the Bit start and Bit length currently cannot exceed 64 for Intel data formats or 71 for Motorola data formats).
- Offset, Scale: The user must provide valid values. The Scale cannot be 0.0.
- Min, Max: The user must provide valid values. The only validation is that the Max exceed the Min. However, the user should consider the following. These values are used to set the Range Min/Max parameters when a CAN channel is added to an SXR test. It is recommended that they be set to the actual maximum and minimum values based on the Data format, Scale and Offset values for integer data formats. For example, if the Data format is an Unsigned 16, Max is computed as 32767.0 * Scale + Offset, and Min is computed as -32768.0 * Scale + Offset.
- Units: There are no restrictions on user input for this. To be compatible with Vector applications, use only letters, numbers and underscores (_).
- Data format: Select from the Data format pull down (SLSB, UMSB, ULSB, SMSB, FMSB or FLSB). For more information, see Table 2, CAN data type parameters in SIE file metadata.
- Invalid value: There are no restrictions on this value. However, it is currently advised that this be set to the Max or Min value for channels that use any of the integer Data format options, assuming the Max or Min value is defined using the recommendation provided above.
- Request msg: This field is optional and allows the user to specify a CAN message to transmit. When used, the field should consist of 8 hexadecimal digits specifying the CAN message ID, followed by 0, 2, 4, ... or 16 hexadecimal digits specifying the CAN message data bytes. The high-order bit of the CAN message ID specifies a 29-bit "extended" CAN frame. Valid message IDs range from "00000000" to "000007ff" (11-bit frames) and from "80000000" to "9fffffff" (29-bit frames).
This field is often used to specify a message that should be used to poll an ECU (a connected CAN device) for a parameter value, but can be used for any purpose.
If a "Request msg" is not set, and the user selects a "Request rate" other than "Off" for an Input Channel, the UI will automatically populate the "Request msg" field with an SAE® J1939.21 "Request" message formed from the channel's message ID (treated as a PGN).
Mode dependent channels/signals are supported for Basic signal multiplexing. Extended multiplexing is not supported (i.e., there can be only one Multiplexor channel/signal for any given Message ID). The user interface validates this limitation. The following parameters can viewed/edited in the Single channel editor only.
- Mode dependent type: Select the radio button to define the channel as a Multiplexor channel/signal or a Multiplexed channel/signal when applicable.
If the channel is a Multiplexor channel/signal, there are no other associated parameters. If the channel is a Multiplexed channel/signal, the following parameters are required.
- Mode bit start, Mode bit length, Mode data format: All three of these parameter values must be the same as the Bit start, Bit Length, Data format values defined for the Multiplexor channel/signal. The user interface validates this requirement. The reason these parameters are required is that the system does not require that the Multiplexor channel exist in the database or the SXR channel set; however, it must exist in the database channel set to be able to export the database to a Vector CAN DBC file.
- Mode value: Enter the Multiplexor value used to identify that the CAN message is providing data for this specific Multiplexor channel/signal. The user interface validates this value. It must be a non-negative integer in the range of the Multiplexor signal. For example, if the Multiplexor signal is Unsigned 8 bit, then it must be in the range of 0 to 255, and if the Multiplexor signal is Signed 8 bit, then it must be in the range of 0 to 127.
CCP channels/signals are supported to a limited (introductory) degree for the eDAQXR and eDAQXR-lite only. CAN databases with any CCP channels/signals cannot be exported.
- Protocol: This is a read only, temporary identifier used to denote that the channel is a sourced channel, such as CCP. The value shown has no meaning for users.
When editing is completed, click OK. The information entered in the dialog will show in the spreadsheet grid cells.
Data capture functionality is provided to allow users to view and analyze raw CAN message streams. This is useful when CAN messages available in the actual message stream are not yet defined in the CAN database.
Data capture requires configuration of the following 4 settings. After defining all of these settings, click the Apply button.
- Bit rate: Select among the ten available rates (1000000, 80000, 666667, 500000, 400000, 250000, 125000, 100000, 50000 or 41670). This is the bit rate of the CAN channel source.
- Termination: This is determined by the requirements of the CAN channel source (True or False). Select True or False, based on the source of the channel and the connection to the network. If neither True nor False allow data capture, the Bit rate setting may be incorrect or there are other issues.
- Module: If the XR unit is part of a networked system, select the desired XR unit.
- Port: Select CAN 1, CAN 2 or CAN 3 (only CAN 1 and CAN 2 on the eDAQXR-lite). The CAN channel is connected to this port.
To capture data, enter a value in the Time field up to 7200 seconds to capture all messages in that time period, or enter a value in the Number field up to 10000 to capture that number of messages. Click on the Capture button to start the capture.
NOTE
If values are entered for both fields, the capture will stop when either limit is satisfied. If no value is entered in the Time or Number field, 10000 messages may be captured. To stop capture before either limit is reached, click the Close button. After capture, the number of captured samples shows in parentheses after Value at the top of the column.
Captured data can viewed, searched, filtered and exported.
- Pull down menus allow the Time or Value column to be hidden (one must stay visible) and contents sorted (ascending or descending).
- To find data among captured samples, enter text in the Search field. Search field content is highlighted in the message Time and Value fields.
- To filter data, enter text in the Filter field. Only the message rows with matching text in the Time or Value fields is shown. Clear the Filter field to see all captured message rows. At the top of the Value column, the number of filtered message shows in parentheses with the number of captured messages, such as (173/3004).
- To export data, select message rows with the mouse or keyboard and click the Export button. Selected messages are saved as a tab delimited Text file to facilitate using Microsoft Excel (named
capture.txt
unless renamed by the user). The number of messages exported shows in parentheses at the top of the text document. Note that search results are not highlighted in the exported file.