Error -209836 - The devices in your task cannot be synchronized.

[swiftmoun]

Hi,

I am a new user and I am running this particular synchronization problem.

The project I am working on is using multiple cDAQ devices (analog voltages, thermocouples, digital counter).

Anyway without going into too much details, I created my tasks in MAX and I am calling those tasks from the task const and everything has been working pretty well, progressing well on this project. Doing all the development from my workstation (ethernet cDAQ chassis) has been nice but today I wanted to get actuate the equipment with the VI running to check basic functionality, so I got on the laptop, went to the lab, "reserved" the network device and started the VI. Well, the VI didn't see any of my tasks because apparently they belong to the local machine and aren't shared on the network.

I quickly created those tasks on the laptop, ran the VI and did the basic tests I needed to do.

Back to my workstation, I realized instead of creating those tasks in MAX I should just create them in the labview project so that I don't have to re-create/modify them every time I make adjustments to them.

So I did. However, I get those nasty Error 209836. Went onto some search for example/forums posts and created a ai/sampleclock on the device that has the highest acquisition rate, which is then shared through a property node (Timing /sampleclock.term) to the other 3 devices. I tried starting the tasks that sources the clock first, and last with the same results..

I'd like to share the Vi but it's pretty big and I would probably want to create a simplified project before sharing it, but I was hoping someone had some ideas. and here some specific questions:

- first of all, why is my VI running fine (no error message, I can't check how good the actual synchronization was since my VI isn't logging data yet and it's not a critical thing for my application whatsoever anyway) - but yeah no error message

- the 4 devices in the chassis are: 9201, 9213, 9219, 9421. I am using the 9201 to do the fastest part of the job (pressure sensors running at 1KHz), everything is ultra slow (1-10Hz max). Did i make a good choice using the 9201 as source (I tried onboard clock and ai.sample clock)

- when sharing the clock to the other 3 tasks, can I simply split that clock? do I need to piggyback them one by one, resharing that sampleclock to the following task?

thanks for your help

[ZYOng]

Without seeing the code, I can't comment on what went wrong and how to fix it.

However, you might have just made things complicated. You could simply add all channels from different C series modules into a single task. See Figures 4 and 5 of Signal-based Synchronization of Analog Input C Series Modules with NI-DAQmx in LabVIEW

[swiftmoun]

Thank you, I appreciate the reply and the link.
It doesn't look like I can do a single task for all the modules as they can't operate at the same rate (thermocouples at roughly 10Hz, pressure transducers are wired into the 9201 running at 1kHz, etc).

I will build a simpler VI to try to replicate the issues without all the complexity that's been added already and post back.