CAN HARDWARE

[PALMEI]

Hello for every body


I have started with CAN now, but I'm having same problems. I have a PXI-8461 and a CAN device. For connection to this device, I only use the PIN 2 and PIN 7 directly for CAN Low and Can High. I work with Labview and I make an application to build several objects with different ID and write frames for this objects and read. I create a Interface CAN.
The creation of Interface and objects is fine. The problem is when I try to write one frame to a object, appear one warning 1073094699, NI-CAN Write CAN Object and when I wait for a state to occur in a object there appear a error 1074388991 that order to me verify my cable connections and operations of remote devices.
Is this a problem with my direct connection and I should make the connection that are explain in the NICAN help with a 120 ohm resistor on a terminals High and Low.

Thanks to all

[dhuff]

There could be many reasons why this is happening, but for a start, I would suggest the 3 items below.
1. Hook the CAN ground to your system. There is 1 pin into the 9 pin connector for ground, it should be hooked to your CAN ground to eliminate interference.
2. Check to see if your CAN interface should be externally powered, or internally powered. This is important to sending and receiving correctly. The VBat jumper determines if the device is internally or externally powered.
3. Check to make sure you have at least 1 other device on the bus when using the NI-CAN card, the CAN spec requires 2 devices on the bus, or you will get NI-CAN warnings or errors.

[PALMEI]

Hello

Thanks for the reply

But... in your 2nd item i have a doubt. you are referring my CAN device or the pxi-8461. my CAn device have his power, but in PXI i don't touched.
My device for CAN only have two connectors, the CAN_L and CAN_H.

And one more thing, i put the resistor, but nothing :'(..


Thanks

[dhuff]

The Internal CAN chip for the PXI 8461 can be powered Internally or externally, Look in the NI-CAN manual for the description. If you do not have a manual you can view the one online at the NI link below (everything inside the quotes). I recommend reading it.
NI-CAN manual


The external power would come in on the V+ pin in the 9 pin connector, pin #9.