Labview 2019 and DDE

[Terry_S]

I need to write a labview client to pass data to and from a software (Quizix PumpWorks) that controls a specialized pump.  The version of the Pumpworks software, I have,  is a DDE Server.  I am using LabVIEW 2019, 32 bit. I found the DDE library in vi.lib/platforms.

I have no problems with performing requests, however when I try a poke (See attached) I get a 14012 error (See attached).  I have also attached the DDE section of the PumpWorks manual.

I understand the technology is old and there are better options of communicating between applications, but this is the software I have.  Does DDE still work with Windows 10?  If so, what do I need to do to make this work.

Terry.

[cstorey]

Looks like commands maybe case sensitive.  You have a "P" in "Set_Press1" whereas manual has "Set_press1".  Try lowercase "p" and see if you get the error.

I'm running a DDE client on Win10+LabVIEW 2019 withouth issues.

Craig

[Terry_S]

Unfortunately the case is not the problem.  I changed the command to a lower case "p" and I get the same error.

[cstorey]

Hmm, according to LabVIEW DDE error codes (See pg 38, http://www.ni.com/pdf/manuals/321551a.pdf) the request is for an invalid item.

[cstorey]

Add a short delay or read the status before attempting the poke?  Try reading the pressure, waiting 1s, setting pressure?

Looking at it again, it might be that the value needs to be a float, while you supply an integer.  Try 99.5?

[Terry_S · Accepted solution]

I figured out the problem.  The "Pumpworks" software installs with a demo version of the software that allows you view the software without have the pump connected.  Because I am developing this application for a client and I don't have the pump, I tried a DDE request with the demo version running and had no issues.  However a DDE poke would return an error.  I assumed that because the DDE requests worked, I was doing something wrong for a DDE Poke.

My assumption was wrong, when I arrived onsite, I discovered that the pump needs to be connected and the actual "Pumpworks" software needs to be running to be able to use a DDE poke.