Hello,
We use TestStand 2014 32-bit in order to develop test sequences that is among other used for production test.
I have created custom step types in order for other testers to easier interface with external hardware. The hardware consists of different modules that are inhouse developed, each module has a certain function and up to 16 can be connected together in one bus. We use a RS485 bus together with FTDI usb adpaters to do the communication from the PC to the test system.
The system is modular and can be connected in various configurations depending on the test requirements for the UUT.
Most of the code that interfaces the inhouse system is built in labview 2014, where I have a .lvlibp (packed library, mainly in order to easily move code between different test computers) which is the library the custom step types calls.
The labview project contains lvoop objects for each "module" in the test system, theese objects are stored as references in teststand (DVR) so that the objects are reused and the runtime information is actually stored in the lvoop object and not in teststand (at least for that object). I have tried various methods to do this, for example to actually store the objects as a objects in teststand, but got problems with performance when reading/writing the object back to teststand after each step executed.
The whole packed library is around 10Mb is size, and contains all of the functionality needed, it takes some time to load into memory first time but then acts ok. My problem is that when loading a large object (when looking
If a use a simple .vi that basically writes data to the virtual com port(i'm using VISA here), and then waits for a response, in a loop and measure the actual time for the message to get onto the bus (with a oscilloscope) i get with some tweaking(no tracing etc) a period time of around 3ms from the recieved message to that the next message is sent. I think this time is quite fast and hard to get any quicker with all the layers involved.
The problem I have is when using my objects to do the same thing the load time is quite a lot worse, around 10-20ms, even tough when using a custom step that is quite low level, that basically does the same thing (with some added functionality, crc checks etc)
Is this what I can expect from such a solution that I have choosen?, is teststand "slow" to load objects into memory, or is it my labview code that is slow to load somehow(size of objects? i dont know).