max. sample frequency with "Modulus Breakpoint (on-board re-enable).vi"

[Baboon]

Hi all,

I'm using the PCI-7344 board and I'd like to trigger an external device. The trigger frequency should be very high (> 4 kHz).

Is it possible to realize such a sample rate with breakpoints and an onboard program like: "Modulus Breakpoint (on-board re-enable).vi".

I don't need a visual indicator and so I don't need the 10 ms delay in the second part.

What is the timeout in the first part for?

Thanks in advance for your help.

Best regards

[Jochen]

The maximum frequency for onboard reenabled breakpoints is clearly below 1 kHz.
The new PCI-7350 series motion control boards (e. g. the PCI-7354) have an auto-reenable feature for the breakpoint circuitry and they are capable of generating breakpoints at a rate of up to 4 MHz. So maybe switching to this board would be the best and easiest solution for your application.

Best regards,

Jochen Klier
NI-Germany

[Baboon]

Are there other ways to catch the movement of the motion device? For my application it's not important to get a signal at a defined position, it's important to get a signal after a defined movement.

I'm using two servos with this board. Is there a way to catch directly the encoder signal (Update Period 250 µs) or something similar. If yes is it possible to route this signal to an output or over the RTSI bus to a DAQ board?

Thanks for your help.

Best regards

[Jochen]

You can route the A or B phase of the encoder directly to the RTSI-bus.
I don't understand exactly what you mean with "...it's important to get a signal after a defined movement...". Could you please explain this requirement in some more details?

[Baboon]

Depending on the movement of a xy - stage (controlled by the motion controller) I'd like to trigger a pulsed laser. Maybe every 2 µm I need a short TTL pulse to release a laser pulse.

I tried a software based solution as well as a on-board solution. Both ways are working well but unfortunately the software based solution is limited to 20 Hz and the on-bord solution is limited to 50 Hz.

Because of that I have to decrease Vmax in my application to 100µm/s.

Well , it would be much easier to trigger the laser with an adjusted frequency. The problem is the acceleration and deceleration of the stage. Because of that the pulses will overlap much more at the edges and that's the fact I wanna avoid.

Thanks for your help. Best regards

[Jochen]

Ok, let's talk about RTSI some more. Taking all your requirements into account this could be a solution:

1. Route phase A or B of the encoder to RTSI
2. Use a counter of your E-Series board to generate a pulse train and use the signal you have routed to the RTSI as timebase. This way you can generate a pulse at configurable multiples of the incoming encoder pulses.

Jochen