VISA events

[Eugen Graf]

Hello, if I use VISA event "Serial Character", I get follwing error Message:

Error -1073807315 occurred at VISA Wait on Event in SK_Task_Read_Parse_A.vi->SK_Interface_A.vi->SK_Main.vi

Possible reason(s):

VISA: (Hex 0xBFFF002D) The event queue for the specified type has overflowed. This is usually due to previous events not having been closed.

Can anybody say me, how to get it away and why it appears?

I tryed to discard occurences before waiting on event, I tryed to enable/disable event before/after I wait on it. But it comes again and again.

Eugen

[Eugen Graf]

No answers. Nobody uses serial port? It's too specific?

My last BD is following.

http://forums.lavag.org/index.php?act=attach&type=post&id=5622

Eugen

[i2dx]

QUOTE(Eugen Graf @ Apr 24 2007, 10:35 PM)

No answers. Nobody uses serial port? It's too specific?

My last BD is following.

http://forums.lavag.org/index.php?act=attach&type=post&id=5622''>http://forums.lavag.org/index.php?act=attach&type=post&id=5622'>http://forums.lavag.org/index.php?act=attach&type=post&id=5622

Eugen

Eugen,

I use the RS232 VIs for serial communications, and I never had any serious truble. I've never heard of this issue, therefore, I can't provide an answer. The best ressource for such issues is the NI website and if you can't find any entrys for that error# there, I'd suggest to contact an AE @ NI support.

[Eugen Graf]

QUOTE(i2dx @ Apr 25 2007, 08:15 AM)

Eugen,

I use the RS232 VIs for serial communications, and I never had any serious truble. I've never heard of this issue, therefore, I can't provide an answer. The best ressource for such issues is the NI website and if you can't find any entrys for that error# there, I'd suggest to contact an AE @ NI support.

Ok, I deleted all Event VI from my BD and replaces them by normally Wait VI -> error is avay now, but my program is no more event controlled.

It's a pity.

Eugen

[Eugen Graf]

No more suggestions?

Eugen

[chrisinlf]

QUOTE(Eugen Graf @ May 7 2007, 04:18 AM)

No more suggestions?

Eugen

I am currently working this issue in LabView 8.2.1 and am experiencing exact same error.

I don't want to do a primitive polling method, as I am launching 3 simultaneous serial port monitors from TestStand

(Probably LabView monitor VI with 2 clones on different Com Ports)

They all need constant communication with each other and with TestStand and polling is a pretty clunky way to

go in this "event driven" day and age.

1 Possible issue is that I am not using NI Serial Port Hardware, and although it is a shame, some of their software

and drivers only (fully) support their hardware especially when it comes to advanced features.

I may end up writing this in C# if that is the case.

Hope to report success in a day or two...

[jdunham]

QUOTE(chrisinlf @ Dec 16 2007, 07:18 PM)

I am currently working this issue in LabView 8.2.1 and am experiencing exact same error.

I don't want to do a primitive polling method, as I am launching 3 simultaneous serial port monitors from TestStand

(Probably LabView monitor VI with 2 clones on different Com Ports)

They all need constant communication with each other and with TestStand and polling is a pretty clunky way to

go in this "event driven" day and age.

1 Possible issue is that I am not using NI Serial Port Hardware, and although it is a shame, some of their software

and drivers only (fully) support their hardware especially when it comes to advanced features.

I may end up writing this in C# if that is the case.

Hope to report success in a day or two...

If you are doing constant communication, then polling is no big deal. Of all the reasons to decide between LabVIEW and C#, that's just about the least important one.

Just poll the serial port 10 times per second, and read all bytes available. If you're handling a little data, then 10Hz is no sweat. If you are handling tons of data (which means your baud rate is pretty high) then it's probably way more efficient to process the input at 10Hz then to run your code for every new byte.

If you are reading the port in a subvi containing a loop with a wait function, then you may want to wait 0ms on the first iteration in case your data is already available at the serial port.

The serial port is asychronous anyway, so you can't count on any specific timing of the data arrival. That would seem like the main reason to use VISA events. If you simply must be event driven, then just write a polling loop, and put all the characters into a queue as they arrive. Then when NI comes up with a fix, you can replace your workaround.

[elyness]

QUOTE (Eugen Graf @ Apr 24 2007, 12:20 PM)

Hello, if I use VISA event "Serial Character", I get follwing error Message:

Error -1073807315 occurred at VISA Wait on Event in SK_Task_Read_Parse_A.vi->SK_Interface_A.vi->SK_Main.vi

Possible reason(s):

VISA: (Hex 0xBFFF002D) The event queue for the specified type has overflowed. This is usually due to previous events not having been closed.

Can anybody say me, how to get it away and why it appears?

I tryed to discard occurences before waiting on event, I tryed to enable/disable event before/after I wait on it. But it comes again and again.

Eugen

I know it's been a long time since your post. I just discovered this problem myself. The solution, in LabVIEW 8.6 anyway, it to close the Event reference after the event occurs. The wait on Even vi returns the event reference. Just use a normal Visa Close on this reference and you should be good to go.

Eric