Anybus CAN - Profinet IRT ' error passive '


I’m having trouble establishing communication between a TI microcontroller and a CAN - Profinet IRT anybus communicator, I have the state ‘error passive’.

List of what’s already been checked:

  • Terminating resistors on both ends , reading of 60ohms on the bus.
    -2.24v between can_hi and gnd, can_lo and gnd, which seems a good idle voltage.
  • Bit rates set to 1Mbit on both.
  • CAN ID set to 29bit on both.
  • CAN configured to send 4 bytes of data from microcontroller and receive 4 bytes on the anybus communicator.

I see nothing on the can listener, is this because the anybus module is in error passive and will stop the microcontroller from transmitting?

What could be the problem?


First, I would try a different bit rate, like 125 or 250 kb/s to see if you get traffic at that rate.

Were you able to try a different bitrate?

Hi Kyle,

Thanks for your suggestion and sorry for the slow response.

I have tried with a bit rate of 125 kb/s and still no luck, I still have the error passive status.
The CAN subnet status on the gateway module is solid green and showing no errors?


Can you please share the article number of the Anybus? Is this a AB7328?

Is the TI microcontroller on the CAN network or ProfiBUS network? What is connected on the other side of the gateway?

Where are you seeing the “error passive” state?

Can you share your configuration (.hcg) file?

You said LED 5: CAN subnet status is green and steady, what is the status of the other LEDs?

Hi @zlowndes,

Hi Kyle,

Article number is AB7320-B.

The TI controller connects directly to the Anybus module over CAN bus. The Anybus is then connected directly to the S7-1500 PLC via Profinet.

The error passive state is shown in the Diagnostic/Status tab of the Anybus Configuration Manager.

can_irt_25_02_21.hcg (2.5 KB)

Zac Lowndes

What are you seeing in the CAN Line Listener? Please share the data.

Hi Kyle,
I receive nothing on the CAN Line Listener. When measuring the bus with a DVM I read 1.5v on can_low and 2.55v on can_hi.

In that case you either have a connection problem or the TI is just not sending any frames.

No, this will not stop a node from transmitting.

Error passive - A node goes into error passive state if at least one of its error counters is greater than 127. It still takes part in bus activities, but it sends a passive error frame only, on errors. Furthermore, an error passive node has to wait an additional time (Suspend Transmission Field, 8 recessive bits after Intermission Field) after transmission of a message, before it can initiate a new data transfer. The primary passive error flag consists of 6 passive bits and thus is “transparent” on the bus and will not “jam” communications.

Thanks for your feedback.

Did you have the opportunity to look at my configuration file?

Yes, I don’t think the configuration is the issue. It should work. Do you have a USB-to-CAN device (like this) that can read the raw traffic on the bus?