PCI CAN Series 2 card Auto Acknowledge

[swap15]

Hello,

Does anyone have an idea about auto acknowledge function in PCI CAN Series 2 card.? Does this card provides this function?

If yes, how can I turn ON the auto acknowledge for this card?

Thanks in advance.

regards,

Swap 

[Gibson]

can you clearify the term auto acknowledge?

the Series 2 CAN hw supports the Listen Only Mode. which you can set as an Interface property, see

ncSetAttr.vi in the manual.  If the Interface is set to ListenOnly there wont be any ACKnowledgements issued.

If you want to ACK each frame on the network you need to set the ListenOnly? = FALSE

Listen Only?
Specifies whether to use the listen only feature of the Philips SJA1000 CAN controller.

The Network Interface and CAN Objects can only receive frames. The interface does not transmit on the
network: no ACKnowledgements are transmitted for received frames, and ncWriteNet.vi and
ncWriteObj.vi will return an error. The Philips SJA1000 CAN controller enters error passive state
when listen only is enabled. The listen only mode is not available on the Intel 82527

[swap15]

Hi Gibson,

Thanks for the reply.

Auto acknowledge means does the card issues acknowledgements for every message it receives.

In my case, I have a sensor which sends message every 10ms and if the sensor doesn't get acknowledge for consecutive

10 messages (i.e. for 100ms no ACK) then the sensor goes in reset mode. I want to avoid the sensor going into reset mode.

Also I am getting error in ncWriteObj.vi. (Timeout Error)

I am not sure if my card sends ACK for every message. I didn't set the interface to Listen Only mode.(Listen Only? = FALSE)

regards,
Swap

[Gibson]

ACK is issued by the CAN chip, the NI-CAN card would do the ACK always in listen only=false mode, if the baudrate is set correctly and you use proper bus termination.

refer to chapter 4 of the NICAN manual wich discribes Cable Termination in details