USER CONFIGURABLE APPLICATION AND DAQS (TECH PROGRAMMABLE)

[JCollado]

Hello everyone.

I have been working on project to be used in the Engineering test lab. Mainly Hydraulics component testing.

The idea is to create an application that does not need a LabView programmer to create applications for common engineering tasks.

The Software will:

1. Allow tech to choose which inputs and outputs channels to activate for use and name them according to the purpose.
2. Choose what Data to save to reports (TDMS).
3. Allow tech to measure traces for actuator movements, loads, pressure etc.
4. Configure different steps to do some of the following: Relays for solenoids, Analog Input Condition, Load output, sine wave output etc.
5. Once the software is complete the technician can create new configurations and use them as needed.
6. Technician can edit the steps and or names
7. A few more....

My question is, as any of you worked on a similar project? what are some difficulty that you had? Did you allow tech to control input rate?

I have the software close to development completion. I need to design the DAQS boxes with all the inputs and outputs. One concern I have is that the configuration files created with the configuration VIs take a little too long to load every time the application is started and needs to load the chosen configuration. Should I use SQL instead of files to save all the configurations?  anything else?

Thank you

Juan

[GerdW]

Hi Juan,

any of you worked on a similar project?

Yes, I maintain our inhouse testbench software.

what are some difficulty that you had?

Handling different devices on different communication busses (CAN, CANopen, TCP/UDP/LAN, RS232, DAQmx)…

Did you allow tech to control input rate?

Yes, to a limited amount.

- Points 1, 2, 5 are done with an Excel-based configuration file, as well as defining warning/alarm limits

- 3 is the main point of testbench software…

- 4 & 6 are available for certain pre-defined conditions/items (you cannot allow "anything"…), as well as automatic alarm handling…

[JCollado]

Thank you Gerd.

You use excel to save high number of data points?

I had issue with excel hanging sometimes, which I handled by killing excel and trying again to save. I have liked TDM due to the streaming speed. and it goes to excel by opening.

I'm mostly using one DAQ chassis with 8 modules. This may makes things easier I guess than all you have. Hopefully.

For the sampling rate I guess I have to let them do it. Most of the time for us 1000s/s is ok but sometimes we need higher and sometimes just like a few samples per seconds for long tests.

If they used only 2 channels, do you only get the data from those two channels? I have it that it will use 0 to 4, 5 to 9, 10 to 14 etc . So if they choose 4 channels, I will still use 5  and 10 if they choose 6 to 10 channels.

As far as digital signals in, do you use regular digital input signal cards? I had issues where the digital card did not bring data fast enough to compare switch signals with for example the actuator position. I started using for example one NI9205 for analog inputs and another NI9205 for switch signals so they match in time with the regular AI cards. Do you see any issues with this?

Thanks

[GerdW · Accepted solution]

Hi Juan,

You use excel to save high number of data points?

No, just plain text files - user requests…

(For "high" sample rates I use binary files.)

If they used only 2 channels, do you only get the data from those two channels? I have it that it will use 0 to 4, 5 to 9, 10 to 14 etc . So if they choose 4 channels, I will still use 5  and 10 if they choose 6 to 10 channels.

DAQmx device are handled completely configurable, either AI or DO/AO. (It's all done while creating the DAQmx tasks…)

Other devices based on case-by-case decision: some devices always need to handle 8 channels, other devices (like stepper motors) can be dis-/enabled at need...

As far as digital signals in

No digital inputs for me, just counters… (Well, mostly. Some "special devices" support digital inputs, but we need them seldomly.)

Using AI to read digital signals is perfectly ok!

[JCollado]

Ok.

For the AI channels, I have separate tasks in case structures that are used depending on how many channels the user configures. The same for the Graph. The user chooses which channels to display on the graph.

Thank you. Very Helpful.