Com settings

[FakStory]

Hi,

     I have a very special problem... I can't create additionnal port in MAX. The fact is, I have a device that I don't know which com port he is using. So I need to try some of them ( 0,1,2,3,4,5 or 6)
I'm now using LV 8.5 and MAX v4.3
I've never get this problem before, and by the way, I don't remember exactly how the com port is set. (I thougt it was the same things than using GPIB Visa address, it is naturally recognized...)
Any way, some forum says that I can manually change the visaconf.ini, but I don't have one!!! So I can't modify it...

Thanks in advance

Fakstory

[Dennis_Knutson]

Yes, visaconf.ini appears to be no longer used. I'm not sure where the settings are kept now but I'm also not sure what you want to do. You say you have 6 ports and want to add another. I'm going to assume you are using USB-RS232 converters so are you adding a seventh and it doesn't appear in MAX? Detection of new com ports is automatic and is dependent on the driver for the converter. If it's the same make and model as your other com ports, the driver should be the same and it would be recognized. Does it show up in the Windows device manager.

As far as identifying the others, if these are USB-RS232 converters and you plugged them in all at once and don't know which is which now, unplug one at a time and refresh MAX. Take note of which one is no longer listed and then mark them.

[FakStory]

Hi,
      Thanks for the reply. I'm sorry, but I thinks I miss my explanation...The fact is that I have in all time, COM1 and LPT1 in MAX. Then, when I plug my device, I don't see an additionnal COM port in max... (in addition, I don't really know if my device is really set to COM2, it is maybe COM3 COM4 COM5 or COM6)...I do not have six COM port in MAX. So, I thought I could create a port COM2 in MAX, to try communicated with my device, and then try again with all the COM port remaning until COM6 (by creating a new one each time...)... The problem is, I can't create additionnal COM in MAX. I got this Warning message :

"MAX could not open a VISA session to this static device.  The device was not returned from VISA when finding resources, but MAX was able to use VISA to parse the resource name."
What it's mean?

 I have two tips for you in order to help me... :

Firts of all, Maybe I just don't really understand how COM port is used and it is normal that I can't create one more. (Or there  a problem  here, and maybe it is because I recently install LV8.5...( like a bug.....))
Or, My device is using the COM1, and MAX don't want to allocated additionnal COM port because no device required other port than COM1.

Hope I'm more clear here...

Fakstory...

[Dennis_Knutson]

Is the device a USB-RS232 converter? If so, it should have come with a driver that you need to install. If you did the install, does it show up in the windows device manager as a com port? If it does but not show up in MAX, then it's possible that it is one of the drivers that cannot be recognized by MAX as a com port. There have been some postings about certain converters with this problem. You cannot simply add a com port in MAX. What is the make and model of the converter.

If you have installed the driver and it does not show up in the device manager as a com port, then what does it appear as? Again, it would help if you provided the make and model of this device.

[pankaj]

FakStory,

What is this device that you are trying to use? From your first post, it does appear that you are using a USB-RS232 converter and from what I understood, you don't see any new COM port in MAX even after you plug in the converter. If that is the case, then it is most likely a problem with the converter (e.g. the driver not installed correctly, not installed at all, etc.). It looks like you tried creating static ports and tried to access the created static ports hoping that you could access the ports on your converter. The ports need not be created statically, and if the drivers were installed properly, the ports should have been 'discovered' automatically by MAX.

Regarding 'visaconf.ini', the file is still used but it has moved to a different folder. It is now found (in windows XP) at "C:\Documents and Settings\All Users\Application Data\National Instruments\NIvisa". Please note, however, that we don't recommend modifying this file by hand unless you are absolutely sure what you are doing (and even then, after backing up the unmodified version of the file). This file is automatically modified by MAX when you make relevant changes in your settings.

Pankaj

Message Edited by pankaj on 11-01-2007 11:23 AM

[FakStory]

HI all,
            Thanks for your interrest to solve my problem...

First of all guys, Where did you get in mind I'm using a usb-serial converter? If it was the case, I should already solved it! ...   thanks anyway...

Instead, I'm trying to communicate with a PID controller from omega...The CNI3253-C24 (the C24 mean that I could talk with RS-232 or 485...) But I can't...I called OMEGA engineer, and they have absolutelly no idea about how to solve it...they said that they never see that kind of problem)... That why I'm trying to figure out if it is possible that the problem is in a bad COM port name! It should be the case, because I find the command on the device...(By shorting pin 2 and 3 of the serial port...I re-read the command I sent...) So I suppose that the device don't reconize my command, not because it is not the good string (they confirme us that we send the correct command...in occurence, "*Z02 cr" to reset the device...) But because I don't "knock at the good gate"! In occurence, to the "gate" COM1!...Finally, I want to try to "knock to the gate" COM2, COM3... COM N  ....until I find the good address... But I can't create additionnal COM Port...MAX said that he can't access it or something like that...

There is no USB-Serial here, only a regular RS-232 wire between the device and my computer...

Regards

Fakstory

[Dennis_Knutson]

You made it confusing because you said you plugged in a device and expected a new com port to show up. That is not how it works with com ports. The com ports will be listed whether you have anything plugged in or not. How many physical ports do you have on your pc? You mention com2 through comN. Do you actually have those physical ports? It is rare to find a pc with more than one port these days.

You mention shorting a couple of pins on the com port. Assuming that this is com1, then the loopback proves that the port is working. If you connect to the device and can't communicate, my guess is that you have either wrong settings or the wrong type of serial cable. If you are using a null modem cable, try a straight through one and vice versa.

[FakStory]

Thanks for the answer...

The problem was my serial cable...it was a cross over serial cable...
But I'm happy to read that Com port is independant whether the device is plug or not...that confirme what I tought...
Like you said, my computer is pretty new, and he has only one serial port... Now, just to know, is it possible to replace COM1 by COM2 ? Should I have to delete the COM1? I ask this in case I fall on a device that is set to an other port than COM1...

By the way, Now I can talk with my instrument, but it answer to my command is stange. Per example, When I send *Z02, it is suppose to ECHO this by Z02...But I got V01...Do you understand something about that? In the manual, It says that V01 is a command, and not a answer at all...Nevertheless, it supposes to mean, V01= Data Format...(my string is wrong?!?) He would not answer me Command Error by the appropriate command in the manual?!?...in occurence.. : ?43=Command Error...

Any way... If you think at somethings...

Fakstory

I know this thread looklike I'm dummy, but the device I got make me crazy...This is the first time I got serious problem with a little serial communication...I suppose I miss something and I'm trying to figure it out...I'm refreshing my knowledge!

Thanks again!

[Dennis_Knutson]

Com1 (or com whatever) is just an alias. The actual VISA resource name is ASRL1::INSTR. Since it's an alias, in MAX you can rename it to whatever you want. I don't understand what you mean by a device being set to another com port. An instrument connected to a com port has no idea which port it is connected to and doesn't care.

Can't help with your command problem. You've not provided much information. If you can post the manual or a link to it and the VI you have written (with actual data saved in it), that would help.