CAN Error with PCMCIA NICAN/DS card

[Michael-Continental]

I run my Nican-card on a CAN-Testsystem who simulates CAN-controller from a car. When I connect the Low-speed port of my Dual-speed-PCMCIA-card with this CAN-Bus-System without connecting the cable with the card CAN-Bus is running well. When I connect now the plug with the card the CAN-Bus goes into error state after some seconds and only a reset of the bus (switching off all Can-controller connected with the bus) it is running again (if I disconnect the plug from the card before).
The transceiver is equipped with the two resistors.
When I an running the Bus-monitor from MAX in the following way it gives out an error message and write a report to nicanErr.txt:
- Starting CAN-Bus
- Connecting cable with the Nican-card
- Starting Monitor
- No start of monitor and error-message was produced
- When CAN-bus is offline (CAN-High and CAN-low on High level) I can start monitor without error but no communication.

Is it related with my Nican card (broken) or it is related with cable or transceiver or something else?

[biker2000]

Hello Michael,

I tried this with a network of two low-speed devices that communicate with each other (high busload). When attaching the PCMCIA-CAN cable to the PCMCIA-CAN card, both devices did not indicate any problems. Launching the BusMonitor on the PCMCIA-CAN card then worked without a problem.

I have a few more questions, though:

• What kind of PCMCIA-CAN card are you using? Series 1 or Series 2?
• Does the PCMCIA-CAN card pass the self-test in MAX, before it is connected to the CAN bus?
• Do you also see problems, if you have the PCMCIA-CAN cable already attached to the card before you connect the cable to the CAN bus?
• How many CAN devices do you have in your low-speed network (aside from the PCMCIA-CAN card)?

Regards,
-B2k

[Michael-Continental]

Hello B2k,

- I am using PCMCIA card Series 1.
- Yes, the card passes the hardwaretest in MAX.
- When I connect the transceivers only to the card and not to the CAN-Bus, then Busmonitor runs without error message.
- Aside the NICAN-card there is only one Airconditioning controller and the Simulator for the Rest-bus-simulator on the CAN.
The Teststand is equipped with two LEDs, which indicates the level of CAN-high and CAN-low.
When I am running the system without transceiver and card, I see the LEDs flashing, depending on communication on the CAN-bus. When I connect now the transceiver to the Bus without the CAN-card, there is now significant changing (CAN-low level seems to be a little bit higher because LED stays always a little bit on).
When I connect now the transceiver additionally to the CAN-card first the CAN-low LED goes to permanent high level and after some seconds also the CAN-high.
On Friday I run the system coincidentally with CAN-low connected to Ground. Then it is possible to run the Bus-Monitor in Read-mode with Warning-messages. Writing to CAN causes still errors.

Do you know, what will be checked by MAX in the CAN hardwaretest? Is it possible, that card connects CAN-low with the power supply of the bus and hardwarecheck indicates still OK?

Regards
Michael-VDO

[biker2000]

Hello Michael,

The ‘Self-Test’ in MAX does test most of the CAN card’s hardware, however it does not test the physical layer (the CAN transceivers).
Given that the system seems to work fine, when you ground CAN_L, it almost seems like that there is a problem with the low-speed transceiver of your CAN cable. If you don’t have another CAN cable to compare with, it’s probably best to contact your local NI branch office to get the cable checked or repaired.

One thing you could try before sending the cable out:
Use a short (less than 30cm or 1 foot) un-terminated, powered cable to connect the high-speed port and low-speed port of your CAN cable. Make sure that the two ports use the CAN0 & CAN1 aliases (set in MAX) and then execute the Obj2Obj program (usually installed to C:\Program Files\National Instruments\NI-CAN\Utilities\).
Even though, it’s not ‘OK’ to use high-speed and low-speed transceivers on the same network, this simple test should work. If it doesn’t, it is a good indicator that some hardware defect exists.

Regards,
-B2k