I have problems to communicate with AVL 415 Smoke meter. The self-made .vi and communication has been working for years, but now when I tried to replace the 415 with 415S something strange happened. The newer 415S did not start to work - it gave time out error. I switched back to old 415 and it gives also time out error. As far as I know, I didn´t do any changes in settings during the swap.
The error comes in both cases, when .vi tries to read from the device. The write doesn´t give any errors. I have tried to look the communication with NI Spy and it gives following:
4081. VISA Write ("Smokemeter", ". ASTZ.", 7)
Process ID: 0x0000092C Thread ID: 0x00000084
Start Time: 12:41:52.497 Call Duration 00:00:00.000
Status: 0 (VI_SUCCESS)
4082. VISA Read ("Smokemeter", 100, 0)
Process ID: 0x0000092C Thread ID: 0x00000084
Start Time: 12:41:52.497 Call Duration 00:00:10.000
Status: 0xBFFF0015 (VI_ERROR_TMO)
The similar 415S is running with same vi in other computer without any problems and I have compared the serial port settings, but there seems to be no differences.
I have also trid to communication with test panel in Max, but the result are similar. Read gives time out error. Is it so, that write does not give any error though it wasn´t successful? It feels like there is no communication between port and devices at all.
It is quite a time and your SR haven't been answered yet. I will take the case over starting from now. Could you give me more details about your module? About your AVL 415 and AVL 415S. What kind of driver AVL have? Who did the driver? Was it you or was it the manufacturer? Thank you for your time.
NI Finland Technical Support.
The 415 and 415S uses RS 232 /AK protocol for communication. The .vi we are using in done in-house and there is no specific driver from the manufacturer. For both, 415 and 415S, we have their own vi´s (where is only some minor differences), which both have been working well for several years. The problem occurred now, when I tried to replace the old 415 with brand new 415S, which should have been almost plug-and-play type of operation.
I connected the new 415S and tried to use, but it gave time out error message. Then I switched to back to 415 and its vi, which had been working recently, but it gave the same error. I didn't change any communication parameters(in MAX or in .vi) and I have checked them several times, but haven´t find the solution.
We have another 415S running on other computer with same vi and it works well, with same commands.
I remember we had something similar problems years ago and the my colleague, who is now retired, did some parameter changes on computer and it started working. Are there some other parameters or setups I should check? The parameters that can be seen with probe or with NI spy seems be similar that are in other computer and 415S, which are working.
As I wrote earlier, write function seem to work well, but when it comes time to read there no byte to read, which leads to time out error.
I tried also to connect the new 415S to the computer, which operates another 415S, and everything worked fine. So it seems that the problem is inside the computer.
Could it be an issue with the serial cable or possibly the COM port failed?
Can you swap out the cable or connect to another COM port (and adjust software port assignment as needed)?
This might be computer problem. How many COM-ports do you have? Can you switch to another COM-port and try with it? Also please check the device is found under Windows Device Manager. There is also another thing that you might try. Run MAX as administrator >> Tools >> NI-Serial >> Recover Unused COM Numbers.
Can you check under your MAX Devices and Interfaces >> Serial & Parallel. What do you see there. Can you attach picture of your MAX please.
I believe also, that there is something strange in the PC we are using. Windows device manager sees the port and says it is OK. Strange thing on the computer is, that device manager says there is two com ports (rs 232), but there is only one connector in backside. We have also NI PCI card for four RS 485 ports. I tried to connect the smoke meter to one of those also, but it did not work either. I have also used the "Recover Unused COM Numbers", but it did not solve the problem.
I´ll send you the picture of MAX, when I get abck to office later this week.
There is "Scan for hardware changes" in Device Manager. Open Device Manager >> Enlarge Ports (COM & LPTxxx) >> right click Scan for hardware changes. This should reconfigure your number of COM ports. Are there any changes?
Here comes the funny part! What happend when you remove that PCI-card from your computer? What happend under Device Manager, What happend when you Scan for hardware changes again?
I believe that it is not issue about RS-485 and RS-232. the customer used already the AVL 415 Smoke meter for a long time, but after trying to replace it with 415S something happened and when he switch back to AVL 415 then it is not functioning anymore. He tested the 415S with another computer and it works perfectly.
Either the current computer is not functioning with 415S but it doesn't make sense why switching back to 415 doesn't work anymore. There is something wrong with the current computer.
NI Finland Technical Support