IDTag error and unable to connect

Heiko Epkens 2 years ago in IQANdesign updated by Justin Wagner 2 years ago 6

Hello.  I am a new IQAN user and I am having difficulties.  I found at power up that I had a flashing IDTag error (it is not obvious in the sales literature that one was required) plus I cound not establish a connection via CANbus.  I am using a Kvaser Leaf Lite as my interface.  I read in a forum on this site that the tag resistance for address ) is 294 ohm.  I plugged in a 278 ohm resistance and the issue remained.  I havefour questions:

1.  What is the tolerance on the address resistance value?    

2.  Does this error prevent establishing a connection with a PC over the CANbus?

3.  Does the interface GND need to be connected to the IQAN-MC41 GND?

4.  Does the CAN-A and CAN-B configuration setting need to be set to terminated?  My controller is operating as a stand alone device.

Any help I could get on this would be appreciated.  Thanks.




We've gotten standard resistors to work in a pinch, but you have to bin them to be very precise.

I believe 1% tolerance. It does not work otherwise.

Since it's a stand alone device you actually need a '0T' tag not a '0' tag.


I've programmed without an ID Tag over ethernet, not CAN.

But I've definitely been able to program it.

The program will NOT run however without the correct ID Tag.


I've only programmed over ethernet but I would imagine the ground reference would need to be the same.


The configuration in the software should generally be terminated.

The bus has a 120ohm on the master side (software configured) and one at the end of the transmission line. If you have no other CAN device you'll still need to terminate the bus.

We program over ethernet (C3 port on MD4) due to the low speed of CAN.


As a note, I don't believe a master module cares about the "T" terminating address ID tags. Whether the bus is internally terminated at the master module is based on the "Terminate CAN-" setting in IQANdesign, not the address tag. See the following post:

We also use the Kvaser Leaf Lite occasionally, and it can be very finicky. Make sure you have the correct drivers from Kvaser and be sure to connect the Kvaser to your computer USB BEFORE opening IQANdesign/IQANrun. I strongly recommend using Ethernet if you can. Much quicker than CAN and I've had far fewer issues connecting.

If the MC-41 is standalone, and no other CAN modules are connected, the unused CAN buses should not need to be terminated. The bus you're using to try to connect the Kvaser to should be terminated on each end of the network.

Thank you for the clarification on the termination resistor.  I'm unclear on how to connect via ethernet to the MC41.

The MC41 does not support ethernet I guess looking at the datasheet.

I've never used the MC41, but it looks like it unfortunately does not feature an Ethernet port, unlike the MC42 and MC43 that do and I'm more familiar with. It seems CAN might be your only option.