MultiTrode MultiSmart Installation & Operation Manual page 55

MultiSmart Installation & Operation Manual
7.5.4.2 CAN Status LEDs
Consists of 4 LEDs labelled: Offline, Error, TX and RX.
Figure 59 – CAN Bus Status LEDs
(a) Offline (Correct State: Off)
Off: The CAN Bus sub-system is in Operation mode.
This means that everything is up and running and the Slave (DSP) is completely configured and
sending status data to the Master (Host processor).
On: The CAN Bus sub-system is not in Operational mode.
Slave (DSP) to Master (Host processor) communications have not been established.
This LED normally activates soon after power-up whilst it is waiting for and receiving configuration from
the Master (Host processor). Once the Master has configured the Slave (DSP), then the Master will
send a command to switch the CAN sub-system to Operational mode. The Slave will then start sending
status data automatically to the Master.
(b) Error (Correct State: Off)
This LED indicates errors on the CAN Bus.
This can be due to either a connection or termination problem on the bus, or due to a Baud Rate
mismatch between either the Master or one of the slaves. Bad connections or bit errors (due to poor
wiring or too long a bus) can also cause bus errors.
The Slave and the Master both attempt to recover automatically from the errors, but unless the fault is
rectified, the errors will continue.
Off: Status OK
On: The Slave has switched to "Error Passive" mode on the bus.
This means that the unit will receive but not transmit. This is due to the detection of packet errors on the
bus. The unit will attempt to recover automatically.
Flashing (approx 5Hz): The Slave has switched to "Bus Off" mode.
This means that the unit has stopped communicating on the bus. The unit will attempt to recover
automatically. The auto-recovery mechanism will mean that the total duration of the flashing period will
be short.
(c) TX & RX (Transmit and Receive) (Correct State: fast flash)
Indicates activity on the bus. These LEDs simply flash with the data on the bus.
At high baud rates, the LEDs are only illuminated briefly so they will appear fairly dim - this is normal.
MultiSmart_IO_Manual_R20 Page 55 of 260