Trigger in card CAN NI

[xav_lgm]

Hello,

I would like to know what is the minimum time width that is possible to apply to the trigger in of the CAN card NI.

Best regards for your answer

[kamalb]

Hi

Which CAN card are you using? Do you have  the data sheet of your cards?

Kamal
NIF 

[xav_lgm]

HI Hamal,

My CAN LS CARD is a NI PXI 8460 and I have a datasheet of it but I didn't find the technical information what I need.

Best regards

Xavier

[kamalb]

Hi
Can you precise your question a little bit more please. I am not expert in CAN . Do you want to know what is the frequence able to connect to an input trigger as a digital signal?

Kamal
NIF

[xav_lgm]

HI Kamal,

In fact I send a pulse signal, not a periodic digital signal, and I would like to know the minimum width of the pulse that I can send to the trigger in of the CAN card NI. In other words, It is the same way to find the maximum frequency of signal that I can send on the trigger in, as you prefer. Do you understand more precisely my demand ?

Best regards

Xav.

[DirkW]

Hi xav_lgm,

Because the CAN Board DB 9 connector itself has no Trigger Input, i assume you are up to use the RTSI Lines to Trigger multiple transmits or receives?

In this Case there is a difference for Series 1 and Series 2 Boards in terms of minimal pulse width the board needs to detect a trigger. Series 1 boards need at least 100 us and Series 2 boards need at least 100 ns pulse width. But...

Read the manual on page 10-15:

"When you configure a DAQ card to pulse the RTSI signal periodically, do not exceed 1,000 Hertz (pulse every millisecond). If the RTSI input is pulsed faster than 1kHz on a consistent basis, CAN performance will be adversely affected (for example, lost data frames). "

This happens because every single RTSI Trigger generates an Interupt and this Interrupt has to be handled by the onboard processor.

So in the end the question for you is: Whats the purpose of using the RTSI Trigger instead of sharing the timebase and using a single start trigger to start both DAQ and CAN aquisition for example?

DirkW

[xav_lgm]

Hi DirkW,

thank you for your answer. As you wrote, I used effectively the line RTSI. As the opposite, I would like to generate a pulse from the CAN card NI series 2 on line RTSI. So, the width of this pulse will be constant at 100 ns or it's possible to choose the value of the width into the range ?

Best regards

Xav.

[DirkW]

Hi xav_lgm,

Here is what the manual says: RTSI Behavior specifies whether to pulse or toggle a RTSI
output. This attribute is ignored when RTSI Mode specifies input
(which are always detected low to high):
Output RTSI Pulse: Pulse the RTSI output. For Series 1
CAN cards, the pulse is at least 100 µs.
For Series 2 CAN cards, the pulse is at
least 100 ns.
Toggle RTSI Line: If the previous state was high, the
output toggles low, then vice-versa.

[DirkW]

Hi xav_lgm,

Here is what the manual says:  RTSI Behavior specifies whether to pulse or toggle a RTSI
output. This attribute is ignored when RTSI Mode specifies input
(which are always detected low to high):
Output RTSI Pulse: Pulse the RTSI output. For Series 1
CAN cards, the pulse is at least 100 µs.
For Series 2 CAN cards, the pulse is at
least 100 ns.
Toggle RTSI Line: If the previous state was high, the
output toggles low, then vice-versa.

[DirkW]

Hi xav_lgm,

Here is what the manual says:   RTSI Behavior specifies whether to pulse or toggle a RTSI output. This attribute is ignored when RTSI Mode specifies input (which are always detected low to high):
Output RTSI Pulse: Pulse the RTSI output. For Series 1 CAN cards, the pulse is at least 100 µs. For Series 2 CAN cards, the pulse is at least 100 ns.
Toggle RTSI Line: If the previous state was high, the output toggles low, then vice-versa.

At least means this is the minimum and there are a couple of effects to the real width, which are dependent to your system.

DirkW

Message Edited by DirkW on 04-28-2006 03:51 PM