Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?

Andy L. · ‎12-16-2003

I would like to take a quadrature encoder as an external clock. The good thing at a 3 channel quadratuer encoder is that I can use it in the "X4"-mode which means that the resolution is four times better than compared if you take just one channel (i.e. channel A).
My problem now is that I am not possible to route the "X4" signal to the RTSI bus, so that I am possible to use it as an external clock for an AI-data aquisition.
Is it possible to route this fourtimes faster signal than channel A would be to the RTSI bus?
I am using a PCI-6602 (master) and a PCI MIO 16E-1 card (slave)

rgharrison · ‎12-18-2003

Hi login,

It should be possible. You will need to route the output of the counter to a specific RTSI line and then use that line as the sample clock by the MIO board. The function you will want to use to route the counter output to the RTSI bus is the Route Signal.vi in LabVIEW or the Select_Signal() in NI-DAQ function calls. You will want to use constants such as ND_GPCTR[x]_OUTPUT where [x] is the counter number and ND_RTSI_[x] where [x] is the RTSI line number. Your source is the counter output and your signal is the RTSI line of choice.

Similarly, for the MIO card, you will want to route the RTSI line to the AI Scan Start to route to your scan clock. The constant for this should be ND_IN_SCAN_START and it should be the signal value while your RTSI s
hould be the source.

The point is you will need to route the signal for both cards which amounts to 2 calls (or 2 VIs). Anyway, hope that helps. Have a good day.

Ron
Applications Engineering
National Instruments

rgharrison · ‎12-18-2003

Hi login,

More info for you. As I explained above, you will be able to route using that method but an encoder in measurement mode will not pulse out of the output unless the counter rolls-over. This will only occur at 2^32-1. Therefore, it is likely you will never see a pulse on the output. Hope that helps. Have a good day.

Ron

Andy L. · ‎12-19-2003

Hi Ron

Thank you for the answer!
As you write yourself - I won't have (and actually I didn't had) a signal on the "counter_out" pin. So I can't use it as a signal for routing to a RTSI line and use it as an external clock!
But do you have any other idea which could help me? I tried some VI's where I used "adjacent counters" or where I tried to make a "X4"- signal with two or even three counters - without success. But I will keep on trying.

Thanks
Andreas (login)

LabVIEW

Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?

Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?

Re: Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?

Re: Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?

Re: Is it somehow possible to route the signal from a quadrature encoder in the "X4"- mode (4 times as often as channel A)to the RTSI-bus and use it so as a external clock?