Monitoring a Watlow F4 Controller

[Dennis_Knutson]

The invalid reference usually means you have not selected the correct port. Did you select the com port by clicking te arrow on the right side of the VISA resource name control?

[PChemist]

I did make sure to have the correct port chosen.  I have been delving a little more into the VIs and noticed that found the VISA Read in WLF4 Utility MODBUS RTU Receive Message.vi is generating the error.  I have checked and re-checked the settings listed in MAX and the F4 itself, they match.  Inside the Init VI is give the following message about the error.

"The ID Query failed.  This may mean that you selected the wrong instrument or your instrument did not respond.  You may also be using a model that is not officially supported by this driver.  If you are sure that you have selected the correct instrument and it is responding, try disabling the ID Query."

I know I have the correct port, driver.  Could it be that the 0 Register that it is attempting to read is incorrect? The Watlow F4 manual lists 0 to be "Model, Diagnostics"

Tracing the error back in further leads me to WLF4 Utility MODBUS RTU Receive Message.vi. I have attached a copy of it below with all of the settings intact. Perhaps one of you can see something wrong in there.

[PChemist]

The Saga Continues...

A friend here turned me onto NI Spy and this is what I captured.

1.  viOpenDefaultRM (0x13020DB8)    Status: 0 (VI_SUCCESS)
2.  viParseRsrc (0x13020DB8, "COM4", 4, 4)  Status: 0 (VI_SUCCESS)

3.  VISA Open ("COM4", False, 0, 0, "COM4")  Status: 0 (VI_SUCCESS)

4.  VISA Set Attribute ("COM4", 0x3FFF001A, 100000) Status: 0 (VI_SUCCESS)
5.  VISA Set Attribute ("COM4", 0x3FFF00B3, 0) Status: 0 (VI_SUCCESS)
6.  VISA Write ("COM4", "........")  Status: 0 (VI_SUCCESS)
7.  VISA Set Attribute ("COM4", 0x3FFF00B3, 0)  Status: 0 (VI_SUCCESS)
8.  VISA Read ("COM4", 3) Process ID: 0x00000974         Thread ID: 0x000004F0 Start Time: 14:46:05.843     Call Duration 00:01:40.000   Status: 0xBFFF0015 (VI_ERROR_TMO)

Perhaps this can help elucidate the problem.  As the name says, I am a chemist and have never dealt with MODBUS before.  Thank you all for the continued help!

Regards,

PChemist

[CStaller]

Pchemist,

Did you ever get this resolved?  I've run into the same problem with a timeout error in the read of the receive message.

[PChemist]

Hi CStaller

 I did get it working, I will try to post the VI in the next couple of days. I currently have an experiment running and don't want to intefere with it.

Regards

PChemist

[labviewleroy]

no you wont. as long as someone helped you, who cares if other people have the same exact problem. Your issue is resolved thats the most important thing. 

[PChemist · Accepted solution]

As much as Dennis attempted to help me it was not his advice, in the end, that solved my problem. I solved it through diligent work and reading on my own part. Including learning an old communications protocol that is not in my field or of interest to me.

Due to Leroy's rudeness I will not be posting my solution on the general forum. If someone needs help they may feel free to contact me.

[asdfff]

oh gosh, what are we to do now? Without someone as smart as you who "runs experiments" and "investigates protocols" the community is lost!

[dewilso4]

^^^^ Really??  Wow, too bad he wouldn't help you do your homework.  Maybe if you asked specific questions, you'd get specific answers (ya' know, kinda like he did).  Instead, you say "It's not working, and I don't know why!!  Send me your code that you spent hours developing so I can see if it works for my very specific situation."  Google a little, read some forums, a programmer's manual here and there, maybe even a specification, and one day you'll be able to solve your own problems too.