PXI - How to use DAQmx Start Trigger when channel list contains more than one PXI module

[RagMan]

Can someone help me with this DAQmx issue that happens when acquiring analog inputs from a PXI system when the channel list uses multiple PXI modules (so multi-device AI task with a start trigger).

I developed the code in LabVIEW 2018 (64-bit), and using NI DAQmx 19.6.

I have the following PXI system:

PXIe-1071 4-Slot Chassis

Slot1: PXIe-8301 Thunderbolt 3 Remote Controller

Slot2: PXIe-4302 Voltage Input Module with TB-4302 Terminal Block

Slot3: PXIe-4340 LVDT Module with TB-4340 Terminal Block

Slot4: PXIe-4340 LVDT Module with TB-4340 Terminal Block

My AI Task consists of 9 channels:

PXI1Slot2/ai0, PXI1Slot2/ai1, PXI1Slot2/ai2, PXI1Slot2/ai3, 

PXI1Slot3/ai0, PXI1Slot3/ai1, PXI1Slot3/ai2, PXI1Slot3/ai3, 

PXI1Slot1/ai0

I would like to use /PXI1Slot2/PFI0 as the DAQmx Start Trigger (Start Digital Edge).

I would like to use /PXI1Slot3/PFI0 as the External Clock.

However when I run the VI, I get the error:

Error -89136 occurred at DAQmx Start Task.vi:7220001

Possible reason(s):

Specified route cannot be satisfied, because the hardware does not support it.

Property: Start.DigEdge.Src
Property: Start.DigEdge.Edge
Source Device: PXI1Slot2
Source Terminal: PFI0

Task Name: LVDT & LASER

I am enclosing a test VI (SR_DAQ_Test.vi) and additional subVIs that will reproduce this behavior. It can be reproduced even when using Simulated PXI modules in MAX.

Please see enclosed image of DAQmx Help for Mult-Device Tasks. According to this, the three PXI modules in my AI Task are compatible with each other.

I have also enclosed a snapshot from MAX showing the PXI simulation devices, if you wish to reproduce this issue.

Thanks again for any tips!

[Voyager7277]

HI RagMan,

Please check this document DAQmx Channel Expansion 

Primarly, you have to make sure all the modules must support the configuration specified in the above document. Hope that will help.

[RagMan]

Hi Voyager7277

Thanks for your reply. Yes, I am pretty sure the modules I have are compatible with each other for mult-device tasks. I saw it in the the DAQmx help (see picture enclosed with my original post).

[Voyager7277]

Hi RagMan,

Just curious to know is the issue solved? Have you found anything going wrong with HW setup or configuration?

Thanks!

[RagMan · Accepted solution]

I contacted NI Support and they responded with documents that show that it should be possible since PXIe-4302 and PXIe-4340 are compatible with each other for multi-device tasks. But I could not get it to work. I could have experimented with moving the modules to different slots. Instead I came up with a work-around. Since I have 2 of the PXIe-4340 modules, I used one of them for Start Tigger  and the other for external Clock. So the Start Trigger signal is connected to PFI0 on the first PXIe-4340 (in Slot 3) and the Ext Clock signal is connect to the PFI0 on the second PXIe-4340 (in Slot 4). The PXIe-4302 (in Slot 2) is still in the task but its PFI0 is not used. With this, it is working. Not a full resolution but sufficient for now.

I also noticed that the slot order is important. If I used the second PXIe-4340 (in Slot 4) for Start Trigger and the first PXIe-4340 (in Slot 3) for Ext. Clock, I get the same -89136 error. This is why I think moving the PXIe-4302 to a different Slot might work. But  I am working remotely so cannot try this until I am on-site.

Thanks for your interest!