Current Cost Support Forum

I'm using a .NET application to retrieve the data from my EnviR over the white data cable that was received with the unit. I have downloaded the drivers from the CC website.

I have found that if I leave my PC for a while, the connection on the serial port get disconnected, and thus data is no longer retrieved. After some tinkering, I worked out that this appears to be the powermanagement of Windows shutting down the USB port to conserve energy. How useful, except that the port is in use.

This would appear to be a driver issue not responding to the selective suspend query in Windows (this occurs every 5 seconds apparently) with the correct response, but only after the PC has been running idle for a while (no specific time, but I suspect 30 mins which is my screen power down time, and no the USB port is in the PC, not the screen unit).

Does anyone know if the v3.4.25.218 driver on the Prolific site will fix this issue (CC driver is 3.3.2.102). Unfortunately they do not have a full history revision available to the public, although CC appear to have one.

I had similar problems when I set up my server (HP Proliant micro server / Win 7 ultimate).

I got around it by setting up a new power plan. I can't remember which settings I changed but I think it was mainly Sleep/hibernate after 1440. I've put a full dump of my plan "monitor" at .
Sorry there no nice screen print available.

Just another thought... [Its one of those "have you turned the power on?" type. So just ignore me if I'm off the mark].
I assume you are using the system.io.ports serialport class and doing synchronous reads? Have you set a low readtimeout? On occasions I have noticed the ENVI waiting considerable time, 10-15 seconds, between messages. A low ReadTimeout may break your loop. Of course not setting it is just as bad as it defaults to infiniteTimeout. ...just a thought.

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As a workaround I originally disabled the USB Selective Suspend setting in my power management plan, but after this worked and stopped the disconnections, I've ended up reenabling this, and changing the power management settings in the device manager for the USB Root Hub that the data cable is plugged into. I've set this so Windows will not "turn off this device to save power". As most computers these days seem to have just about one hub per port, this allows all the other USB devices to shutdown nicely, while not affecting the data cable.

I am using the SerialPort class, and no have not specified a timeout. I don't mind the waiting indefinately, although with the limits of the class, this means that unplugging the data cable and then plugging back in is not handled particularly well at this time. Will get around to fixing that one day.

Although the workaround sorts the problem out, I do think that the driver for the data cable, should not allow itself to be shutdown though when there is an active connection on it.