08-20-2010 07:08 AM
I’m designing an application in which I will have ten (10) stations for testing a device via CAN. My plan is to utilize one NI-8473 for each station. The PC will have ten (10) integral USB ports. The code used will be LabVIEW, and will be structured such that each the station is controlled by an independent while loop. There is no need for any interdependence between the stations, and the test takes about twenty (20) hours and will run independently. My question is that will LabVIEW be able to distinguish between the ten (10) USB ports. For example station 1 will utilize USB port 1/ NI-8473 #1; station 2 will utilize USB port 2/ NI-8473 #2; ………; station 10 will USB port 10/ NI-8473 #10.
Thank you,
Chuck M.
Solved! Go to Solution.
08-20-2010 07:34 AM
Hi,
of course, your CAN device will be named : the 1rst will be CAN0, then CAN1..etc..
Just a question : why using ten NI-8473, while 1 can have 31 slaves without repeter ?
Best regards,
Vincent
08-20-2010 07:49 AM
I'm using 10 NI-8473s because the test's, which are complicated have to run independently, including being able to stop and start at different times, so rather than trying to develop difficult code to multiplex 10 stations to one 8473, ie turn the CAN off and on through a switch box I"m using 10.
For another project where I burned in 10 devices on ten stations I multiplexed the 10 stations with a 34970 Agilient mux and the code was difficult and occasionally I would get CAN communications errors.
I don't understand what you mean by 31 slaves without a repeater.
Thank you,
Chuck M.
08-20-2010 07:54 AM
I will also mention a thread discussing Windows reassigning ports when the are plugged into a different usb port. In this case they weren't, it was the motherboard usb "glitching", just a heads up. Not sure how CAN devices are handled in this case, these were RS485 serial com ports.
08-20-2010 08:12 AM
Thank you - Does anyone have experience using multiple 8473 devices where each is attached to a different USB port, and they are being accessed by different independent loops?
08-20-2010 10:08 AM
I use 2 NI USB-9472 devices to control valve solenoids. After configuring the devices in MAX, they can be plugged into differently USB ports with apparent impunity. MAX must recognize the device by a serial number or something. But this a good question for the customer support folks.
08-24-2010 03:33 PM
Because of the nature of Windows switching the resources for the USB ports, MAX associates the device by serial number. I hope that helps.
08-24-2010 03:36 PM - edited 08-24-2010 03:36 PM
I will add the caveat that ID'ing works when the device have recognizable serial numbers, in the case I was referring to the initial serial - USB adapters didn't, the NI ones did.
01-20-2014 02:16 PM
I think you can change the CAN number in
MAX
Select
My System
Devices and Interfaces
NI-CAN Devices
USB-8473
CAN0
Right-Click CAN0
Select Properties
Port Properties Dialog will come up.
There is a field "Interface:"
You can scroll down in this widget and select
CAN0 to CAN63
I have two CANs connected.
CAN0
CAN1
There is an "*" next to CAN1
so I don't pick it when changing the "Interface" field for CAN0.