Tab ‘J1939 ECU - TX-Signals’

This dialog shows the parameter groups that you defined for transmitting then to all other ECUs (broadcast) or to a specific ECU (P2P). In this dialog box, you can activate and deactivate individual groups and modify their parameters. You can also add new groups or signals to the list.

Enable	: The parameter group is transmitted. The parameter group is not transmitted for a local device. For a remote device, the PLC does not process this group.
Type	Broadcast: The parameter group is transmitted to all ECUs. Peer-to-Peer (P2P): The parameter group is transmitted to a specific ECU.
Add PG	Opens the Add Parameter Groups dialog box.
Add Signal	Opens the Add Signal dialog box. The button is enabled only if you have selected a parameter group.

Parameter group properties

General

PGN	The “parameter group number” is a unique number for addressing a parameter group.
Name	Name of the parameter group
Description	Description of the parameter group
Length	The length of the message data (0…1785 bytes). Due to the maximum data field length of 8 bytes, messages with over 8 bytes are transmitted as multipackages.

Transmission settings

These settings are provided only for the TX parameter groups of local devices.
Priority	Priority of the parameter group (0..7). Priority 0 is the highest and 7 is the lowest.
Target Address	The target address is needed for P2P parameter groups only.
Transmission Mode	Determines the time when a parameter group is transmitted (for local devices). Mode change: The PG is transmitted when the value of the signal changes. Cyclic The PG is transmitted after a specified number of PLC cycles (see cycle time factor). On Request: The PG is transmitted on request of another device. Application-Controlled: The PG is transmitted when triggered by the application.
Cycle Time Factor	Number of PLC cycles after which the parameter group is transmitted. Only applies for cyclic transmission.

Signal parameters

General

SPN	(Suspect Parameter Number) One of the numbers assigned by the SAE for a specific parameter in a parameter group.
Name	Name of the parameter
Description	Description of the parameter
Length (Bits)	Length of the signal (in bits: 1…14280).
Byte Position (0..1784)	Start byte in the parameter group (0…1784).
Bit Position (0..7)	Bit position of the start byte (0..7).

Conversion

Conversion	TRUE: The value is calculated with scaling and offset.
RAW Data Type	Format of the raw data: Unsigned / Signed / Float / Double.
Byte Order	Little endian or big endian of the raw signal.
Scaling	The factor (for Conversion =TRUE).
Offset	The offset (for Conversion =TRUE).
Minimum Value	Expected minimum value of the converted signal (for informational purposes only).
Maximum Value	Expected maximum value of the converted signal (for informational purposes only).
Unit	Unit of the converted signal.
ICE Data Type	Resulting data type of the I/O channels.

Dialog box ‘Add Parameter Group’

Database

CODESYS shows all parameters of the database in this tab.
Search	Character string for filtering the PGN list.
Reset	Reset the filter for showing the full list.
Filter	Only PGs of the selected type are shown.
Add PG	Adds the selected parameter group to the TX signal list. Multiple selection of parameter groups is possible.

User Defined

In this tab, you can created user-defined parameter groups.
PGN (18 Bit)	Unique number of the PG (0…262143) that is calculated from the four subsequent parameters. You can type in this value directly into the field.
PDU-Specific (Bit 0-7)	Evaluation of the value depends on the value in PDU Format. If PDU Format is between 0 and 239, then the message is addressable and the field contains the target address. If PDU Format is between 240 and 255, then the message is a broadcast message and the field contains the group expansion.
PDU Format (Bit 8-15)	Protocol Data Unit The format determines whether the message can be transmitted with a target address or always as a broadcast message.
Data Page (Bit 16)	Selection of the page for the PDU format (currently always 0).
Expanded Data Page (Bit 17)	Not used: for future expansions.
Name	Name of the new parameter group.
Length (Bytes)	Length of the parameter group (in bytes)
Priority	Priority of the parameter group (0..7). Priority 0 is the highest and 7 is the lowest.
Description	Description of the parameter group

Dialog box ‘Add Signal’

Database

Signals are added in the same way as for parameter groups.

User-defined

SPN	Suspect Parameter Number
Name	Name of the new signal.
Length (Bits)	Length of the signal.
Description	Description of the new signal.
Conversion	The value is scaled.
Unit	Unit of the signal value (for informational purposes only).
RAW Data Type	Unsigned / Signed / Float / Double.
Byte Sequence	Little endian or big endian.
Scaling	Factor is Conversion is activated.
Offset	Offset if Conversion is activated.