# System signals

## Default signals

Fieldbus Access automatically sets up system signals during its initialization
face. Following signals are created per default. These signals are accessed for
various error information in your application. More information in the [Error
handling](errors) section.

* `fieldbusAccess_CANBusError_CAN#`
* `fieldbusAccess_J1939Error_CAN#`
* `fieldbusAccess_CANopenError_CAN#`
* `fieldbusAccess_CANopenStatus_CAN#`

CAN# is replaced with the configured CAN interface ID, for example CAN0.

| Name           | Description                                                 |
|----------------|-------------------------------------------------------------|
| fieldbusAccess | This part can be changed by setting the --name argument to the runtime. More info in the [Runtime](runtime.html section                                |
| CAN#           | Depending on what can interface that is setup in the config this will automatically change (CAN0, CAN1, CAN2, CAN3, etc.). This is to be able to distinguish errors on a specific can bus.                                                         |

### CANBusError

The system signal `fieldbusAccess_CANBusError_CAN#` receives CAN-Bus errors like
BusOff, StuffError, Overrun etc from the SocetCAN driver.

### J1939Error

The system signal `fieldbusAccess_J1939Error_CAN#` receives J1939 stack specific
errors. More information in the [Error handling](errors) section.

### CANopenError

The system signal `fieldbusAccess_CANopenError_CAN#` receives CANopen stack
specific errors. More information in the [Error handling](errors) section.

### CANopenStatus

The system signal `fieldbusAccess_CANopenStatus_CAN#` receives stack state
specific information like Initialization, Pre-Operational, Operational and
Stopped.