Using BNC PFI0 and PFI1 on cDAQ-9178 as trigger in Flexlogger

[Josvde]

Dear all,

My group has recently obtained a cDAQ-9178 with several sensor modules. 

I would like to use the two BNC connectors on the chassis for a trigger signal to start measurements in FlexLogger (2020R4). My problem is that I can not find where to specify the channel in FlexLogger that belongs to these BNC connectors (PFI0 and PFI1). 

There are workarounds but they involve sacrificing inputs on the sensor modules. 

Any hint is appreciated.

Cheers, Jos

[Kristofer_Klemett · Accepted solution]

Jos,

FlexLogger does not currently support the built-in PFI lines on the cDAQ chassis, so you will have to use an input on one of your sensor modules as the trigger signal.

Other customers have asked for supporting the built-in PFI lines as well, and we will consider adding this feature in a future release of FlexLogger.

Also, we noticed our documentation isn't clear on this, so we have a work item to clarify that as well.  Apologies for the confusion.

Please let us know if you have any other questions/feedback about FlexLogger!

Kris Klemett

Section Manager, Product R&D

NI

[Josvde]

Thank you for the answer Kris. I'll look forward to future releases.

For now I'll just define an I/O input as trigger on the NI 9401 module. The problem with this fix is that in some cases I need that module to output a start/stop pulse to a set of pumps. It seems that I cannot use the NI 9401 bidirectionally in FlexLogger, am I correct? If so, I would like to suggest to consider making bidirectional use of the NI 9401 possible in future FlexLogger releases as well.

Overall I'm really pleased with the user friendlyness of the cDAQ/modules/FlexLogger-combination. Setting up and monitoring a new experiment with a custom dashboard can be done in no time. 

[Kristofer_Klemett]

Jos, you are correct.  You cannot configure the 9401 for bidirectional use in FlexLogger at this time.  That is an item on our backlog that we will also consider for a future release, and I appreciate your request for this!

We do support bidirectional use on the NI 9402 in FlexLogger, so if that 4 channel module will work for your use case, you can consider that.  (The NI 9401 has some hardware differences which made supporting bidirectional use more effort in FlexLogger, which is why that's not completed yet.)

I'm glad to see that you find the combination of cDAQ and FlexLogger so easy-to-use!  Thanks again for your feedback!

Kris Klemett

Section Manager, Product R&D

NI

[Kristofer_Klemett]

Just to clarify, when I say bidirectional, I mean having a mix of input and output channels configured on the same device at the same time.  This is possible on the 9402 as I mentioned.  The 9401 can be configured either for all input channels, or for all output channels, but you can't have a mix of inputs and outputs on the same 9401 at the same time.  Addressing this particular limitation is the item on our backlog that we will consider for a future release.

I hope this helps avoid any confusion on this topic.

Thanks,

Kris Klemett

Section Manager, Product R&D

NI

[Josvde]

Hey Kris,

Thank you again for the answers and suggestion. I do have one slot left on the cDAQ, adding another I/O module would be easy. It is just that when ordering the system I did not expected to need it because of the BNCs on the cDAQ and my initial interpretation of the word 'bidirectional'. I was looking for the cheap solution first 😉

I agree it is good to underline the difference between 'bidirectional but all pins are either IN or OUT within the same experiment' and 'bidirectional with option for mixed individually configurable pins'. 

Best wishes, Jos