Weak Data Transfer From Ph Meter To Daq Factory

[izumi1]

After a while, the pH from the pH meter stops transferring to Daq Factory. Could you please help with a line of code that re-initializes the data transfer in the case that it stops? 

 

Thank you!

 

Here is the sequence:

 

device.phmeter.Purge()

private string datain

while(1)

   try

      datain = device.phmeter.ReadUntil(13)

      if (left(dataIn,2) == "pH")

         ph.AddValue(strToDouble(mid(datain,3,1000)))

      endif

   catch()

//      ? strLastError

      device.phmeter.Purge()

   endcatch

   delay(0.1)

endwhile

 

 

[AzeoTech]

You can do this two ways.  First, you can try just adding:

 

device.phmeter.initcomm() inside your catch():

 

catch()

//      ? strLastError

      device.phmeter.initcomm()

      device.phmeter.Purge()

   endcatch

 

Second, you can create a secondary thread that checks the timestamp of ph and reinits the comm port:

 

while(1)

   if (ph.time[0] < systime() - 30)

      device.phmeter.initcomm()

   endif

   delay(10)

endwhile

 

Third, you should consider replacing your USB to serial converter, as that is what is causing the disconnect.  Get a different brand and one rated for industrial use, not a cheap $20 one off a random site on the Internet.  I always recommend the ones from SeaLevel.com.

[izumi1]

When I inserted device.phmeter.initcomm() inside the catch(): 

- I got ALERTS from Daq Factory 

 

Then I used the secondary thread and the pH still stopped logging in my ph channel. 

 

I am not using a USB to serial converter, I am plugging in the USB cord (from the pH meter) directly into COM 6 of the PC.

 

Do you have any other suggestions to fix this problem? Sorry, thanks for all of your help so far! 

[AzeoTech]

Can you tell me what the alerts are?

 

Alas, you are using a USB to serial converter, its just buried in the pH meter which is too bad because you are subject to their whims.  Just for future reference, if you can, buy devices with serial or ethernet connections instead of USB, then if you have to go USB, you can get a converter.

[izumi1]

Yeah, when I inserted device.phmeter.initcomm() inside the catch(): the "Alert" on the bottom right corner of Daq Factory would keep lighting up every time it would log the pH. 

[AzeoTech]

Go to View - Command / Alert to see what the alert message is.

[izumi1]

It keeps saying unable to initialize COM6;can't access port,probably in use by another app.

 

but nothing else is using COM6, I even switched to COM7 and I'm getting the same error.

[AzeoTech]

You can't just randomly pick comm port numbers.  You should go into the windows Device Manager, find the comm ports listed there and figure out exactly which one the device is showing up on.  I know you have no choice, but this yet another reason I dislike USB->serial converters.  They move around on their comm #'s, especially if you plug them into a different USB port.

[izumi1]

I did that. Device Manager says it's reading from COM7 so I just changed COM6 in Daq Factory to COM 7

[AzeoTech]

Just to be sure: you didn't just rename the port, you actually changed the port number to 7?  Also try rebooting to be sure no other software is claiming that port.  And try reiniting the port in daqfactory:

 

device.ph.initComm() 

 

and make sure you get the in use error every time.

[izumi1]

When I go to Device Configuration and click on phmeter, COM6 and COM7 are both options. I clicked on COM6 to delete it but it won't delete. I have phmeter running with COM7 but since COM6 is still there, could that be what is causing the problem? 

[AzeoTech]

1) Go into Device configuration

2) click on Com6, then click on Configure.  It probably won't do anything.  If it does, set the Port to 0 and hit OK

3) click on Com7 then click on Configre.  Make sure the port says 7, hit OK.

 

If all else fails, email us the .ctl doc.

[izumi1]

I did both of those things, COM6 didn't do anything when I clicked delete and nothing happened when I clicked configure.

COM7 is set to port 7. 

I'll e-mail you the file. Thank you!

[izumi1]

pH Electrode Measurements.ctl

 

here's the .ctl

[AzeoTech]

Are you sure you want Xon/Xoff flow control?  I rarely ever see any device that requires any sort of flowcontrol nowadays, and would especially not expect it with something that supplies its own USB port and virtual comm port driver, since the driver itself could handle the flow control.  It may be as simple as that being set to None.

 

Don't worry about the COM6 port.  Even though it shows up in the list, it doesn't actually exist.  

[izumi1]

The manual for the pH meter says to set the flow to Xon/Xoff.

 

Do you have any other suggestions?

 

I am now using a USB to serial converter and I'm still getting the same Alert and the pH stops logging after a certain period of time. 

I used the device manager and made sure I am using the right COM port, could it be something in the sequence? 

[AzeoTech]

When it stops, can you do 

 

device.ph.initcomm()

 

at the command /alert window and have it restart?