Assign permissions to com port

I am trying to get help or information on assigning permissions for com ports. I am getting communication read errors on software that we use to read meters. The com port is correct in device manager and for the particular software. Communication is good,
as long as we are logged in as administrator. We have assigned admin rights to the software for the users, but it appears that the com port needs admin priviledges assigned. The software vendor recommended giving admin rights to the user over the entire machine.
I would only do that as a last resort. Does anyone know how to assign permissions on com ports?

Hi,
If you don’t want to grant the administrator privileges for your users, I suggest you distribute the software via Group Policy.
You may refer to: Permissions and rights have been removed from the Power Users group in Windows Vista
http://support.microsoft.com/kb/2028493
Also, if these COM ports are usb based, check the usb devices too.
As I known, it is not possible to access Advanced screen or Advanced settings without the administrator rights. This issue is more related to hardwre device drivers, you'd better follow the device manufacturer's instructions. I think, you may give admin
rights to the user over the entire machine as software vendor recommended.
Hope it helps.
Regards,
Blair Deng
Blair Deng
TechNet Community Support

Similar Messages

HyperTerminal sees a COM port but VISA does not

It should not be possible that HyperTerminal sees a COM port but VISA does not. Does anyone know why or have any ideas?
Here's some more info: I wrote a LabView (LV) program and deployed it (via the Application Builder) to some of our production department's PCs (some Windows XP and some Windows 7). We use it to set up products we design and manufacture through our device's USB serial port. The USB port is actually a virtual COM port (VCP) - a USB to Serial converter or "bridge". We have a custom driver for our device and since each device's USB bridge chip is programmed with a different serial number, every time we connect a new device to the PC the installer runs and assigns a new COM port number. This is so our customers can use multiple devices on a PC. Fine. On one of our production PC's we were close to COM900 ports (HyperTerminal sees only up to COM256) when suddenly Win7 would not allow any more. We were able to uninstall orphaned (non-present) COM ports from DeviceManager ("DM") by starting it from a command console (DOS window) with a special command-line switch, "set devmgr_show_nonpresent_devices=1" then "start devmgmt.msc" (I have this in a batch file). In DM View menu you can "Show hidden devices" and uninstall them as if they were connected. I've also tried uninstalling them the normal way when the device was actually connected. Either way, sometimes, not always, depending on the COM port number, after reusing that port number by installing a new device which picks up that old, freed-up number, LV VISA doesn't see it. In other words, when "Refresh" is clicked in the COM port VISA list box, any new devices installed should be and normally are seen. (Refresh is not needed if the application is started after the device's driver is installed. It is only need if the LV application is open with the new device is added.) However, HyperTerminal does see it and lists it in the Properties screen, the "Connect using..." list box. And the port works with HyperTerminal. (Of course we've tried rebooting after uninstalling and/or reinstalling the device, with the same results.)
When I've spoken to the NI Applications Engineers in the past about serial port issues (not about this problem) they have confirmed that if HyperTerminal can see the port then NI VISA should also see it. This is crazy. I am posting this in hope that someone can shed some light on this problem.
Thank you. -Ed

Good catch. Yes, we're using the Silicon Labs CP2102 and have created a "custom driver" installation package. Our new PCBs have a factory-programmed chip, so the PC reuses that COM port (COM3 on that PC). The problem is when we we re-program the CP2102 (setIDs exe) with our PID, and device strings (including the S/N), the PC runs our installer and assigns the next COM port number. I was hoping that maybe it would go up to 64K or something! Anyway, it surpassed COM256 but we ran into this problem when almost up to COM900.)
There is a registry entry for each SN device, which shows the assigned port. If we delete the key with regedit, the COM port database (don't know the file name) still has the port number. That's where Device Manager comes in. It seems to allow us to manually delete the ports, but it would take quite a while to delete 900. (I was trying to make a batch file for DevCon, but couldn't get it to see the HW ID of the devices in need of deletion.) So we tried manually deleting a few. After doing that Device Manager shows that Windows (and HyperTerminal) can reuse the port number when a new device (new SN) is installed, but, as you know from this post, VISA cannot see unless I manually add it in MAX.
I can't see how it has anything to do with the Silicon Labs driver. I might have to delete ALL of MY devices, then uninstall the driver files, reboot, then reinstall, as you suggested with the SiLabs driver. However, I don't see how VISA will now see these changes. VISA must have it's own database. That's what I thought deleting the ports in MAX would clear out, like a fresh install, but apparently not.
I've been through Silicon Labs' tech support on other issues and they've been able to help on some. I could run this by them.
BTW, have you noticed that Silicon Labs' chip and driver, while faster than NI's own "bridge" or serial-USB converter (I returned it because at $100 it's performance was worse than a $20 converter you can buy in Staples), is substantially slower than a real serial port? For example, our device can transmit 250 readings per second (a 12 byte string). A real serial port used with my LabView program can keep up, i.e.., graph & tabulate at that rate, but with a VCP we only get about 70 RPS. Same code. Can't figure this one out. They say the've tested the driver to 900 KB claimed. We're using 115KB here. Anyway, the VCP driver makes it look like a COM port which LV thinks it is. Why is it slower than a real port when the USB should be able to work almost 10 times faster than I'm using it (up to 1024 bytes per mSec per the full-speed USB spec, which SiLabs claims they verified)?
Anyway, I appreciate your help. Thanks! -Ed

Cant assign com port to resource name

I'm setting up a vi that will be used on a target pc, where the com port available on the target (com5) is different from the ones available on my development pc. I'm trying to create a constant or control at the input of my hardware vi that identifies the com port, but it won't let me assign com5, apparently because my development pc doesn't have com5 available. If I give it a selectable control that I can select at run time on the target, it defaults to a com port not available to the target and when launched it hangs up. How can I hardwire (make default) the resource name to a com that is unavailable on my dev. pc?

Mark, please see attached screenshot of my vi. I tried what you suggested. The drop down constant that is wired to the CILXS vi is what pops up when I create control, so that is the text format I duplicated with the unwired string constant shown above it. Of course, when I tried to use it I deleted the drop down constant and wired in the string constant, and it didn't work. The error message says insufficient location information. Any other ideas?
Attachments:
com.JPG ‏79 KB

Programmatically assign com port

Hi
I have an applicaton that uses USB-Serial adapters (Keyspan). This system is in an open lab situation with multiple users and multiple laptops runing the LabVIEW program. Each computer's registry assigns different comports to the Keysapn USB-Serial converter. I've been able to query the registry and determine what com port Windows has assigned to Keyspan.
How do I take this info and programmatically assign a com port or Visa resource name that LabVIEW is to open? Is there some simple Visa property node for "Resource Name" that I am not finding or is this more difficult than my awareness?
All of the laptop computers will be using Windows XP and LabVIEW 8.6 runtime engine.
Thanks
Glen

You can take the com port name as a string and wire it into the VISA functions. It will generate a coercion dot, but it will work.
Message Edited by Ravens Fan on 03-16-2009 10:30 AM
Attachments:
Example_VI_BD.png ‏1 KB

Serial COM Port to TCPIP

I saw a lot of posts that deal with this, however: I have a test rack with 24 UUTs, each has a usb to Ethernet adapter. I want to use each adapter to talk to the UUT with the same IP (can't changed it it's static). I need to be able to go through a com port and communicate to a specific UUT, knowing that I am communicating through this specific com port, not any other of the 24.
I saw a few virtual drivers, that seem to do this, but has anyone done anything of this nature before? I know I can create a NI Visa resource in NI MAX but that doesn't help me, because I can't link a com port to that resource, can I?

rsmrostov wrote:
‎You wrote that you have a USB-to-Ethernet adapter. Did you mean the TRIPP-LITE extender?
yes
That is simply a USB extender, no conversion to Ethernet. - obviously
Then why did you describe it as a USB-to-ethernet adapter?
rsmrostov wrote:
Does your device speak TCP-IP or serial? -TCP-IP
Where is the USB-to-serial adapter, and what model is it? non, there's a driver that comes with the device, that must let you talk to TCP/IP
Is it integrated into the DUT? - most likely, not sure to be honest, as I am helping out one of the guys who plain just doesn't know.
What can you tell us about the DUT? - Linux based device, has a fixed IP
You showed us a screenshot of MAX, listing several COM ports. So, those COM ports somehow exist on your system. You also said that only one of them is connected to the DUT. If this is true, then the COM port must be created outside of the device (for example, a USB-to-serial adapter). However, if the device doesn't use serial communications, then it doesn't make any sense to have a USB-to-serial adapter at all, because there's no easy way to run TCP over serial.
It sounds like you need to do some research on exactly how your DUT works, what types of connections it offers, and what protocol it uses. If you absolutely need to connect to multiple devices, each of which have the same IP address, I would recommend that you get a bunch of cheap home NAT (network address translation) devices, often seen as a home/office router (allows you to connect multiple computers to a single internet connection). Assign each one a unique IP address within the same subnet, plug them all into an ethernet hub or switch, and plug one DUT into each router. Configure the router's internet address to match the subnet of the DUT, and set each router to route all incoming connections to the IP of the DUT.

Lab View is not detecting two com ports of system

Hi,
In my PC, three com ports are there COM1, COM4 and COM6. But when we create new visa resource name, lab view is detecting only COM1 port. I want to know is there any way to correct this.
Regards
Shivakumar Singh

Hi,
First of all check if the ports are visible in the NI MAX. If not, you can try to Create New Port by going into Measuremenmt & Automation Explorer. Assign the Port values accordingly. This can be done by right clicking on the Ports (Serial & Parallel) section of the Devices and Interfaces tree.
Regards,
Deepu.

Wrong Com Port order with PXI - 8422 in a Win2k system

While using my PXI-8422 on WinNT4.0 and NI serial driver ver 1.44 Ports were assigned com numbers top to down. ie Port1-COM1 , Port2-COM2 , ...
However on win2k and NI serial driver ver 1.45 ports were assigned com numbers in the reverse order. ie Port1-COM4 , Port2-Com3 ,...
And when i try to change com assignments the sytem hangs while trying to access the ports.
Any idea how to solve it?

Topcu,
We have seen the reverse order behavior before for serial devices in Windows 2000.
The first thing is to make sure that you tried to change the com assignments properly. If you only tried to change them in Measurement and Automation Explorer, it may not work. Here is the proper way:
1. Select Start>Settings>Control Panel and double-click on the
System icon.
2. Click on the Hardware tab and click on the Device Manager button.
3. Double-click on the Ports (COM & LPT) icon.
4. Double-click on the port you want to configure.
5. Click on the Port Settings tab.
6. Click on the Advanced button. The Advanced Settings dialog box
should pop up.
7. Change the COM number in the COM Port Number field. (You can
use a COM number that is designated as in
use, as long as no hardware
is actually using that COM number.)
If this is how you tried to reassign your ports and your system still hangs, please go to www.ni.com/support and click on Request Support in the black panel to let us know.
Sarah Fenney
Applications Engineer

VISA "Find" not seeing COM port but Win7 sees it

Allo. I'm trying to communicate via virtual com ports with a device with an FTDI chip. The device with the FTDI chip has both a USB type B port as well as a 9 pin dsub port, and I need to verify both ports work.
I'm using a laptop with Windows 7 and my program is in LV 2010. I have a Sabrent USB to serial cable to test the dsub port, and a standard USB cable to test the other port. I've installed the latest FTDI drivers and when I plug in both cables and look under Windows Device Manager, I will see both of them under unique COM port settings (usually COM4 and COM 5). So Windows sees and recognizes both virtual COM ports, and no yellow warnings.
However when I run the "VISA Find" function in LabView, it only sees COM5 (the Sabrent serial cable) but not the COM port using the USB type B cable. I send the results of the "VISA find" to a display and it will show other ports, like the parallel port, so I know it's seeing more than one port.
Any ideas why Windows can see the two COM ports but the "VISA Find" function can only see one? My guess is there's something with the FTDI driver set up.
Amateur programmer for over 10 years!

Yes, but its not for the faint of heart!
You can probably do what you want by using the refresh "F5" in MAX or add this token
[VISA-CONFIG]
ShowRegisteredDevOnly = 0
to C:\ProgramData\National Instruments\NIvisa\visaconfig.ini
Another thing to try is to recover the unused COM Port numbers each time you change the device. By default Windows will "Save" those previously connected COM port numbers an if it sees the device again it will re-assign the old number. This means that the COM number keeps getting larger and larger. At some point the PC's BIOS will say that's rediculous and you will experience trouble.
Programatically you could call
C:\Program Files\National Instruments\NI-Serial\NiPortConfig.exe to launch the same utility. there is probably even and unpublished switch to click just that one big button for you but I can't find it.
It looks like you may be running into some part of this known issue
Jeff

Multiple COM Ports after installing to peer to peer Brother Laser Printers.

My particular situation is one Iv'e never encountered in thirty years of working on micro-computers. I have a peer to peer LAN hooked through a Gateway (4-Port \ WIFI (Frontier=Telco) ADSL\MODEM\Router made by Net Gear. I have 4 Wireless ip's and 3 cat 6
wired ip presences on the LAN. All the network is MS WIN 7 64 bit software and all the computers are 64 bit hardware, I have the home Group numbers matched up and everything shared on the LAN side of the Gateway. The problem on one of the clients (Dell
Notebook, 2 years old) is that when I installed the two cd's with the Brother suite of software (HL-2270 DW Monochrome laser printer and a (MFC-9130 CW Color Laser all in one Printer\scanner\fax\copier everything was fine for a while until the two printers
began to jump their dynamic assigned IP's. So, I statically assigned on the two printers with the ip address they worked on after rein stalling both software cd's ; uninstalled the old software first of course. I am hunting for a fix, something in the OS or
Registry short of a clean reload of the whole Dell notebook to bring the ports back to 3 LP and 4 com ports! They read 4 lpt ports and 24 COM ports presently.
Thanks For You Time,
Jamie Skinner
[email protected]

Have you gone into Devices and Printers, right clicked on one of the printers and selected "Printer properties" and then the
Ports tab and tried deleting the unwanted Com ports there?
Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”

Programmatically identifying com ports by their physical port number

I have a system with a NI PXI 8420/16 card. Once in a while a glitch in my PXI system occurs such that my physical RS-232 ports get re-assigned different com port numbers. Then I have to go into MAX and reassign my aliases to re-align my LabVIEW application with my port hardware. Is there a way to stop these glitches from happenning? OR is there a way to programmatically identify a physical port's com number?
Solved!
Go to Solution.

See if this helps: http://forums.ni.com/ni/board/message?board.id=170&message.id=490257#M490257

FTDI virtual com port driver (VCP) and Labview 2009 - random connection loss

Hi,
I am using an FTDI chip to go from USB to serial communication (FTDI Driver: 2.06.00). It seems to work at first but then after some time the connection gets lost ("connection for the given session has been lost" or "I/O error"). This happens in MAX as well as the built executable of the program I am running. Latest VISA drivers are installed - 4.6. I have tried flushing the buffer before and after communication with both visa clear and visa buffer flush vis. The lost connection seems to happen randomly.
I have seen other threads about this issue but they never reach a resolution. One thing i notice is that there are two FTDI devices in this system and only one fails, however when I unplug the working device the one that fails is able to connect again.
To sum up here are the system specs:
Windows XP SP3
FTDI 2.06.00 and older 2.04.02 drivers both fail.
2 FTDI devices on the system - they do get assigned different COM ports
Labview 2009 run-time
VISA 4.6 run-time
Thanks for any help.

We use Targus ACH63US Super Mini USB 2.0 4-Port Hub. It doesn't require external power but if you have a high power device you will have to plug the Targus hub into two usb ports on your pc (one provides power and the other does power and data transfer). They provide the usb Y cable to do this.

Write among COM ports in the same PC without cables

How can I write to the memory address(es) of a serial COM port? I would like to send data from one serial COM port to another in a manner similar to the that of the 'Simple Data Client' and 'Simple Data Server' vi examples. This must sound strange since this is exactly what a null modem cable will do, externally. I would like to eliminate the cable connection between COM ports that exsit in the same PC and communicate between them, internal to the PC, somehow.
Currently, I am using a LabVIEW vi to read a serial message on COM1, translate it, send the trsanslation out on COM2, so that a separate windows program (no .DLLs to interface with LabVIEW) can read the message on COM 3. COM 2 and COM 3 are connected by a null-modem cable. This requires three COM ports, and two serial cables. I realize that I can use a physical loop-back jumper on COM2, for instance, where I send and read the translated message on COM2, but I still wonder if there is a method for doing this in memory, or something. Is there a way to accomplish the same objective with one cable (into COM1), no loop-back jumpers, and only two serial ports? In summary, I want to read on COM 1, translate in LabVIEW, then write directly to another COM port, internally, without using a serial cable. Can the 'IN PORT' or 'OUT PORT' vi's apply here? Are these tools only for parallel ports?
Hope this is not too confusing.... It seems like I am always trying to do something with LabVIEW that was not meant to be done....
Thanks.

Thank you. If I pay the price they ask, this looks like it will create and share virtual COM ports - exactly what I need. However, I would really like to find a way to do this in LabVIEW, such that I do not have to make my application dependent on another piece of third party software. The 'Simple Data Client.vi' and 'Simple Data Server.vi', included in the shipset examples, seem to do this for TCP/ IP ports. I wonder why the COM ports cannot be addressed at the memory level, in a similar manner???

Can two users share a COM port?

I have a system services Labview executable that opens a VISA session on a COM port.
But I also have a User Interface VI that needs to communicate with the device on same COM port.
Is this possible? Can I use a Shared Variable to keep the VISA Resource name and have multiple users (one at a time) communicate with the device?

LabVIEW semaphores and all other LabVIEW objects like queues, notifiers, events, etc are not only process local objects only but even application context local only. While this makes no difference for built applications it is important inside the development environment as each LabVIEW project lives in its own application context (and tools started from the Tools menu run in yet another context). To do what you want to do, you need to implement some form of interapplication communication as Mark already mentioned. Or you can access named OS semaphores by calling OS APIs.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

How can I write to multiple daisy-chained network serial addresses through a single COM port?

I have a VI to write to 3 PI Mercury motor controllers using daisy chained RS232 connected via a Prolific USB-to-Serial adapter. I know that it is possible to talk to the individual controllers because the PI terminal that I have recognises the addresses of multiple controllers and designates them Device 1,2,3. The VISA resource name when configuring the port just comes up as COM5 most of time, with seemingly no way to specify an address on that COM port. Occasionally the VISA resource is ASRL5::INSTR and as this is disconnected and re-connected, this address moves up a number (e.g ASRL7::INSTR). Can anybody tell me how I can configure my serial communication to allow me to individually communicate with the different devices through a single COM port?

What does the manual say about addressing? RS-232 is not multidrop, the resource name is correct, and there is no additional configuration needed. There would have be a specific write in order to address a certain controller.

How to use shared variables to address multiple Watlow controllers on the same COM port

Hello,
I am trying to use LabVIEW 2010 to control 4 Watlow temperature controllers on one COM port. 3 are Model 96 and 1 is an EZ zone controller. Each controller has a unique modbus address, and I am trying to read from and write to individual registers (such as closed loop setpoint) using shared variables. I am getting return data when reading (although the data appears to be invalid), but am unable to change the value in the register by writing. How can I be sure that the Modbus server is sending commands to the correct controller?
Chuck
Solved!
Go to Solution.

Peter,
Thanks for the reply. I have actually solved that problem. I realized that the Modbus server address has to be the same as the controller's Modbus address.
I have, however, run into another problem. Perhaps you could help me with that. I have a system with 4 Watlow controllers, 3 are series 96 controllers, one is PID only and 2 are ramping. The 4th controller is an EZ zone. I am using RS485 for communications and the controllers are all wired in parallel for communications and power.
I have set up 2 Modbus servers for 2 of the controllers.
This is the first I have ever worked with Modbus based communications. I have successfully programmed using the Modbus read/write VIs, and am wanting to move to shared variables. My questions right now revolve around addressing, Modbus I/O servers and COM ports. Specifically, at this point, I know the addresses need to match up between the server and the slave device (Watlow controller in my case), how many servers can I create and use on one COM port? If the number is limited, is there a way I can specify an address that I want the server to talk to? Will the broadcast mode work to request data values from the controllers?
I'd appreciate any information you can help me with, or if you could point me to some sort of concise 'How-To' for Modbus communication.
Thanks.
Chuck

Assign permissions to com port

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