Maximum cable length RTSI-Port

[MichaGue_01]

Hello,

I am using a NI PCI-6133 and a NI PCI-6259. I want to synchronize the timing source of both DAQ devices by using RTSI-Port. Both devices have a different length, so the rtsi port is not next to each other (see picture). The available RTSI cables from NI are to short.

Because the rtsi connector ist just a normal 34 PIN connector, I tried a floppy disk cable, like this: http://www.cartft.com/catalog/il/585?gclid=CMmRw4C1zc0CFU4o0wodaUgK6Q

I configured the rtsi cable in daqmx and configured DEV2 (PCI-6259) in my labview application to use clock source from DEV1 (PCI-6133). An error appeard, that told me there is maybe to much noise on the timing signal.

Is there a maximum cable length for the rtsi port?

Thanks a lot and best regards,

Michael

[Alexander_Sobolev]

I doubt length is the problem

What clock rate are you transmitting? 10M should be fine

We are using CC2205R-BKB (similar length) to connect 3 boards, it works fine and more convenient than flat one you are using. To sync 4 boards we have manually assembled cable from flat cable and crimp connectors, it also worked. 

Though we are not transmitting clock. With regular trigger signals we have verified cable does not add jitter - it is around 100 ps.

[gregorelectric]

Hi,

there is a cable officially offered fron NI: 

777562-05

Extended Length RTSI Bus Cables for 5 PCI or AT/ISA Devices

RTSI Bus Cables - National Instruments
https://www.ni.com/en-us/support/model.rtsi-cable.html

RTSI Bus - NI High-Speed Digitizers Help
https://www.ni.com/docs/en-US/bundle/ni-scope/page/rtsi-bus.html

So that leads me to the conclousion, that length is not the problem. Maybe the specs of the cable you are using are insufficient. Could you provide a Screenshot of the error?

[stockson]

A lot depends on the quality of the cable. If one of it's parameters, e.g. capacitance, is over some limit it will just not work.