Daqmx AI and AO, ni 9234 and ni 9263

[Lahan]

Thank you both for your replies.  I will have to look at it when I get back to work.

[Lahan]

Hi guys,

The complexity has just increased, in my opinion anyways.  I am to sample 8 AI channels in two ENET-9234.  It is not so much important to be in phase with original signal (function generator for testing) as is with the two Enet 9234. 

I noticed the enet 9163 has pfi 0 and pfi 1, so my question is can I use pfi 1 to share the same clock between the two (one being the reference clock and the other use that clock as well) to synchronize or keep the data in phase with one another.  It would be easier if I have the room for the 8 slot ethernet chassis, but i don't.

Below is a section from the enet 9163 datasheet.  Note *4 mentioned that "sample clock out" is module dependent and I can't find out whether the ni 9234 module has a sample clock out.

Thanks

WLS/ENET-9163 Digital Triggers Back to Detailed Specs
Static Characteristics
Number of terminals		2 bi-directional, individually settable
Pull-down resistor		49.9 kΩ ±0.5%
Input voltage protection 3		±20 V on each pin
Power-on state		Input
Required minimum input pulse width		100 ns
PFI Functionality
PFI 1		Sample Clock In, Sample Clock Out 4
PFI 0		Start Trigger In, Start Trigger Out, Pause In, Reference Trigger In

Maximum Operation Conditions
Level	Min	Max
IOL output low current	—	8 mA
IOH output high current	—	–8 mA

Digital Input Characteristics
Level	Min	Max
VIL input low voltage VIH input high voltage	0 V 2 V	0.8 V 5 V
IIL input low current (Vin = 0 V) IIH input high current (Vin = 5 V)	— —	–15 μA 120 μA

Digital Output Characteristics
Parameter	Voltage Level	Current Level
VOL	0.5 V	6 mA
VOH	4.0 V	–6 mA

[JustinP]

Hello,

You can inport/export the master timebase of the NI-9234 as described in this document. This master timbase is what the sample clock is derived from and would keep the two modules in phase with each other. This would be set up in software. 

Regards,

Justin

[Lahan]

Hi Justin,

Thanks for sticking around. 

I've read the manual and it said the NI 9234 can export or import its master timebase.  But I am unable to get it to work due to the fact that I can not find the mastertimebase.src and mastertimebase.rate in the daqmx timing property node.

I manage to find an example here where two wls/enet 9215 is synchronized using the same sample clock:

http://zone.ni.com/devzone/cda/epd/p/id/6124

Tried it with the enet 9234 and the error I am getting is error code 200414, "requested sample clock is invalid" for slave.

I have tried running just one enet 9234 and exporting its sample clock at the pfi 1 terminal, and the scope showed the exact clock pulse as my sample rate in the program, 25.6ks/s.

So I guess my question is if the enet 9234 is capable of importing a sample clock and use it to synchronizing itself with a twin?  Or I am omintting something in the example program?

Here is my program, light mod to the example, just changed the device names.

[Lahan]

oops, attached the wrong file, disregard the top.vi from above,

attaching the correct one

[JustinP]

Hello,

You can export the master timebase from NI-9234 to another but you cannot export a trigger, therefore you will need an additional module that can export a trigger to both devices to synchronize them.  This document describes how to trigger the NI-9234.

Regards,

Justin