Can Dnet PCI card work at 16Mhz CAN bit timing?

[Krista S]

Hi Lupita,
 
It seems to me that the change in your device has caused this issue. When you say it no longer works what do you mean? Are you getting any errors?  If so what are they and what are thier descriptions? A little more information on how it's not working and how it is supposed to work would be helpfull.

[Paul M.]

Lupita,You mention that the bit
timing DID change, but later on say that the baud rate did NOT change.
Are you sure the device is still operating at 125kBit? Chances are that
we are operating at a different baud rate now. As long as your device
conforms to the standard high-speed CAN physical layer, then the NI
DeviceNet card will work with it.  Bit timing parameters are
not set in LabVIEW, but in Measurement and Automation Explorer.  You
can configure the interface hardware baud rate or bit timings there. If
you know the specific bit timing registers you want to use, you can
also specfiy those there.  Hope this helps!

[frankwu]

Hi Lupita,If a device runs at 125kbps, then NI-DNET can communicate with it (no matter what oscillator is in the device). If a device uses a different oscillator, then the manufacturer should
change its firmware to tune the CAN bit timing for the baud rate.The problem may be that the new device doesn't run at 125k baud rate after the oscillator is changed.You can check the problem by the following way. If it is true, please ask your device manufacturer to fix the CAN bit timing.1. launch MAX2. select you CAN card > Protocol > change to "CAN'3. select you CAN port (CAN0) > Bus Monitor4. connect your old device and make sure that 2 messages appears in the bus monitor5. connect your new device. If no message appears, then the device doesn't run at 125kbps.Regards,Frank


max.jpg:
Loading Image...

[Lupita]

Hi,
I ran CAN and got the following CAN information (new device first). Is it possible that the NI-dnet card (CAN controller Intel 82527 and Philips 82c250 transceiver) is just not able to handle the new CAN transmission rate (1.45 Hz)?
I was able to establish communication with a SST card (SJA CAN controller and TJA transceiver)
 
Thank you.
 
 


CAN_frames.jpg:
Loading Image...