J1939 Interface Configuration

CAN Bus Configuration

To configure the CAN bus of your controller, refer to CAN Bus Configuration.

The CAN bus format is CAN2.0B for J1939.

J1939 Manager Creation and Configuration

Proceed as follows to create and configure a J1939 Manager, if not already present, below the CAN_1 node:

Step	Action
1	Click the Plus button next to the CAN_1 node in the Devices tree.
2	In the Add Device window, select J1939_Manager and click the Add Device button. For more information on adding a device to your project, refer to: • Using the Hardware Catalog • Using the Contextual Menu or Plus Button
3	Close the Add Device window.
4	Double-click J1939_Manager (J1939_Manager). Result: The J1939_Manager configuration window appears:
5	To configure the J1939_Manager, refer to Programming with EcoStruxure Machine Expert / Device Editors / J1939 Configuration Editor / J1939 Manager Editor / Manager Editor found in the EcoStruxure Machine Expert online help.

ECU Creation and Configuration

Proceed as follows to create and configure Electronic Control Units (ECUs):

Step	Action
1	Click the Plus button next to the J1939_Manager (J1939_Manager) node in the Devices tree.
2	In the Add Device window, select J1939_ECU and click the Add Device button. For more information on adding a device to your project, refer to: • Using the Hardware Catalog • Using the Contextual Menu or Plus Button
3	Close the Add Device window.
4	Double-click J1939_ECU (J1939_ECU). Result: The J1939_ECU configuration window appears:
5	To configure the J1939_ECU, refer to Configuring J1939 ECUs.

Configuring J1939 ECUs

As an overview, the following tasks must be generally accomplished:

• Add one J1939_ECU node for each physical J1939 device connected on the CAN bus.

• For each J1939 device, specify a unique Preferred Address in the range 1...253.

• For each J1939 device, configure the signals (SPNs) in the TX Signals tab. These signals are broadcast by the J1939 device to the other J1939 devices.

  Refer to the device documentation for information on the supported SPNs.

• Associate the SPN signals with variables in the J1939 I/O Mapping tab so that they can be processed by the application.

• When signals have been added, verify their settings in the Conversion window of the TX signals tab, for example, Scaling, Offset, and Unit. The J1939 protocol does not directly support REAL values, which are instead encoded in the protocol and so must be converted in the application. Similarly, in J1939 units are defined according to the International System of Units (SI) and therefore may need to be converted to values of other unit systems.

  Examples:

  • The Engine Speed signal of parameter group EEC1 has a property Scaling=0.125 that is encoded into a raw variable of type ARRAY[0..1] OF BYTE. Use the following ST code to convert this to a REAL variable:

    rRPM:=(Engine_Speed[1]*256 + Engine_Speed[0])*0.125;

  • The Total Vehicle Distance signal has properties Scaling=0.125 and Unit=km, which are received in a (raw) variable of type ARRAY[0..3] OF BYTE. Use the following ST code to convert this to a REAL variable in mile units:

    rTVD := (Total_Vehicle_Distance[3]*EXPT(256,3) +

    Total_Vehicle_Distance[2]*EXPT(256,2) + Total_Vehicle_Distance[1]*256 +

    Total_Vehicle_Distance[0])*0.125*0.621371;

  • The Engine Coolant Temperature signal of parameter group ET1 has properties Offset=-40 and Unit=C(Celsius), which are received in a (raw) variable of type BYTE. Use the following ST code to convert it to a REAL variable in Fahrenheit units:

    rEngineCoolantTemperature := (Engine_Coolant_Temperature - 40)*1.8 + 32;

For more details on how to configure the J1939_ECU, refer to Programming with EcoStruxure Machine Expert / Device Editors / J1939 Configuration Editor / J1939 ECU Editor / ECU Editor found in the EcoStruxure Machine Expert online help.

Configuring the M251 Logic Controller as an ECU Device