Window 7 through prolific USB to RS232, work with Modbus (watlow F4D)

[Ott]

Hi,

It's a strange issue - when work with WindowXP, after connect USB to RS232 and connected through Modbus, I could talk to it. Now with upgraded window 7, same setting (rate 19200), the com port could not be detected. if I type it in at MAX, click Validate the error message is "0xBFFF0011". If disconnect Modbus, just WIndow 7 and USB to RS232, after disable and Enable the COM port under device manager (Control panel), Click Validate in Max, it's a success message. Labview 2010 is used.

Any one worked with using window 7 to control the Watlow F4D?

Any comments?

Thanks,

Ott

[Josh_B1]

Hi Ott,

What USB to RS 232 device are you using?

Regards,

Josh B

[coyotejr83]

I'm using a Prolific PLM2303 chip USB- Serial to comunicate LAbView VI to a serial device on WIndows 7 servicepack 1. I can launch the VI but after a while (sometimes 20 minutes, the most has been 1:30 hours) I get a bluescreen crash. What is happennig?

[coyotejr83]

I'm using a Prolific PLM2303 chip USB- Serial to comunicate LAbView VI to a serial device on WIndows 7 servicepack 1. I can launch the VI but after a while (sometimes 20 minutes, the most has been 1:30 hours) I get a bluescreen crash. What is happennig? It doesn't happens if I use simply Hyperterminal. The machine has a Intel Core 2 Duo What else shoul I say in order to help? I've tried 2 differents converters with the same result

[RavensFan]

Are you continually closing and reopening the com port in a loop?  If so, don't.

What chipsets do the other converters you used have?  I remember seeing posts where people have had problem with converters based on the Prolific chipset, and the problem went away when they used a FTDI chipset based converter.  Search the forums on that topic and see what others have had to say.

[coyotejr83]

I've given up on crank that projecto on that PC, I've asked my customer to send me another PC because exactly the same program on MY Lap top works with no problem, Both are Windows 7 service pack 1 based, I run the program on my Lap Top using the same converter and the same RS-232 device. I've asked some guy computer especialist and they told me than the problem could be the processor (Centrino on mine and Core duo on theirs)

Just to answer yout question: Yes, I'm opening, writing, reading, flulshing the send buffer and closing on every reading cycle (500 ms), but, as I told you, when working on my lap top I have no problem at all. About the chipset, I have no the data currently, as I told you, I've send the computer back, but one of the first thing I made when the failure show, was to update the chipset directly form Intel's website

[coyotejr83]

Eureka! Well, first I'vo gotta say that I went back to my customer after a while and ask him for a second chance to solve the roblem, let's say it was a matter of proud.

I've found that the USB-Serial converter installed a set of two .sys files: the driver itself named ser2pl.sys and another file named serenum.sys. Well, the bad guy was serenum.sys. I replaced it with an older version downloaded from Internet... E voilá!

I hope this helps someone in the future, I think it's quite impossible that I'm the only guy in the world having this problem, and some kudos wouldn't look bad in my curriculum.

Cheers everybody!

[teritask]

I was just browsing through the forum and saw Watlow communications, which I've done extensively. I'd like to commend you for actually posting your solution! Too many people do not do that and it ticks me off when I see the same problem I'm having and no one bothered to update their results. I try to update all mine, even if it was a dumb error on my part.

Thanks again.

[Vanir]

One thing to remember is that your windows RS232 manager will sometimes change the ASTRL number of your RS232 port.  You need to play the "am I plugged in" game with your RS232 device.

1) disconnect your RS232 device.

2) Quiry the list of plugged in devices (make a list )

3) Insert your RS232 device.

4) Quiry the list of plugged in devices (make a list )

THe new RS232 device is yours.  

There is no logic or reason as to when these RS232 port re-assignments occur. They mostly occur after windows updattes that require a restart. 

I have attached the software that I use to control a Watlow FR4 controller.

If you have trouble then contact me at    www.gpibsoftware.com 

[dognic21]

Could you elaborate a little more on these two driver files that you referenced in this post? I am having a similar issue to what you were. I have seemed to stop the bsod from happening but when I read the watlow temp for a while the port just freezes up and I can not close the program or reconnect to the watlow without restarting the computer. I slowed my reads down to every ten seconds to allow the modbus communications to have ample time to perform its read. I run a db9 to usb serial converter to write and read from the watlow. I only right once at the beginning of the program and read temp every ten seconds. It will run for 10 to 45 minutes then freeze.