Re : Synchronization DAQ and CAN (PCMCIA)

[Barto]

Hi everybody.

I'd like to know if it's possible to do a hardware synchronization between SCXI-1600 and a "PCMCIA CAN/2 series2"?

I have the cable to connect the PCMCIA connector "sync" to the PFI7 and PFI0 of the SCXI-1600, but in Labview, when I select the Dev1/PFI7 as source of "DAQmx Timing.vi", it doesn't work.

Hope you could help me.

Thanks.

Barto

[Barto]

Hi,

I have bound the PCMCIA/CAN2 Series 2 to the SCXI-1600 with a synchronization cable (sold for the PCMCIA card) and when I install a RTSI cable in MAX, there isn't SCXI neither Can card. I think that this is why in Labview the error says that the timebase has been disconnected.

Could someone help me please?

Thanks for your help.

Barto

[pierreR]

Barto, please look at this topic.

Message Edité par pierreR le 10-27-2006 05:11 AM

[Barto]

Yes, I saw this topic, but I though the PFI7 and PFI0 could serve.

So... There's a clock and a trigger who output. So why can't we use them to sync with a PCMCIA Card?

It's a signal! And what comes into the RTSI cable is a clock signal?

Could you explain to me, in order to understand, please?

Thank you.

Barto

[pierreR]

I think the following is clear :

"it looks like there is a misunderstanding here. The CAN Sync Start with NI-DAQmx.vi synchronizes a DAQ plugin board and a CAN board using RTSI.
RTSI is the real-time system integration bus. The National Instruments timing bus that connects DAQ boards directly, by means of connectors on top of the boards, for precise synchronization of functions.
This bus is only available on NI plugin boards but not on an external device like the SCXI-1600"

I don't see the utility to share clock between CAN card and DAQmx card, could you explain your goal ?

[Barto]

Hi Pierre,

The utility is to have signals that are sync on the same clock.

Look. I have sent a bipolar signal ("signal carré") to the SCXI-1314, and to the CAN series 2 card (PCMCIA). When I lauch the acquisition of DAQmx and CAN at the same time in Labview, there is a little time elapsed between the CAN signal and the DAQ one, which isn't the same in each acquisition.

What I want is the two signals coming together at the same time.

Thanks for your suggestions and help.

Barto

[pierreR]

Hey Barto, I understand your matter.
What is the variation delay which is introduce between DAQ and CAN acquisition ?
Personnaly, I think that this delay and his variation is normal due to information publication delay on BUS CAN.
How many node have you on your bus ? What is the send period of the information you receive on the bus ?
CAN is not as faster as DAQ !!!
To recept info on CAN you must wait that the information is published on the bus !!

Message Edité par pierreR le 11-07-2006 02:55 AM

[Barto]

Hi Pierre,

The delay between DAQ and CAN acquisition is around 10-15ms.

What do you mean by "node"?

I understand what you say: do you mean that I should wait until I have quite samples to read, and read them after, on the both materials?

Thanks.

Barto

[pierreR]

What is the refresh delay of the data you want on the bus CAN, what is the period of emifsion of the frame which contains it ?
When I speak of nodes I speak of the different devices that listen and write on the bus.