Wednesday, March 28, 2012

Getting CellLog8 Data Out

I've been helping a contact with getting the CellLog8s to transmit data to a PC and thought that the info might be useful to anyone else trying to get the slightly quirky data transfer to the slightly quirky German LogView software to work.

First thing to note about the CellLog8s and PC connections is that the USB port on the logger is not isolated from the PC and is not isolated from the battery pack being monitored.

The CellLog8s should have opto-isolated data lines to USB.  But they also wanted to be able to power the thingy from USB so that means a connection to the PC...  The later product (PowerLog) comes with a cludge of a solution in that it has a USB cable with the power pins not connected!  Rubbish solution, as immediately you'll loose the original "isolated" cable and use a normal one and BOOM!

I know about the issue and have from my own experience blown up a hand-held oscilloscope by running it from the DC-DC converter on the solar system instead of the internal batteries only.

I get away with plugging the CellLog8s USB into my little laptop because I make damn sure that I only run the laptop on batteries and not plugged into ANYTHING else (even use wi-fi for network connection).  It's all good if the PC is running on internal power and is not connected to anything where the solar battery power can escape back to itself in a loop and... BOOM!

That's why all the data interfaces on the Morningstar charge controllers are opto-isolated.

Next is that you need to install the Junsi serial port driver that came with the device on a mini CD.  Do not just plug the CellLog8s into the PC as Windows 7 will find the device and install a built-in USB serial port driver that does not work.  Install the Junsi one first and then plug the device into the USB port and check that the Windows USB notification says it has found and successfully configured the Junsi driver.

Also note that you must be using a non-64 bit version of Windows.  Windows 7 comes in 32 and 64 bit flavours and the Junsi drivers do not work with 64 bit Windows.  This is not because they don't work but because Windows 7 64 bit enforces a "no install" security policy for unsigned 3rd party drivers.  The 32 bit editions do not enforce this.  They'll complain that the driver is unsigned but allow you to install it anyway.

I've managed to get the LogView thing to work without problem.  I don't log continuously but have managed to download the CellLog8 on-board log file with no trouble.  I'm using v2.7.3.481 (which came on the CD with the CellLog8).  You don't need to mess about with the device file.  Go to the Device> Choose Devices and Ports menu.  In there, use the drop down lists to choose Junsi and CellLog8.  It even shows a picture of the device when you select it.

Then all I did was tick the "Automatic start recording" option and select the COM port to talk to it over in the "RS232 Seriel" drop down list.  The CellLog8 driver you installed earlier (you did install the supplied driver, not rely on the Windows one?) will be listed as "Junsi something or other COM x".  You have to have the CellLog8 connected to the PC via the USB cable before starting LogView for it to find the Com port that gets discovered and enabled by Windows as soon as you plug the CellLog8 in.  If you don't plug the logger into the USB before starting LogView, it won't find the serial port.

The "Automatic start recording" option means that whenever you start LogView, it tries to connect to the port used last time for the CellLog8 and it opens the recorder session in LogView (ready to receive any data).  If CellLog8 is in logging mode it will transmit individual data every 2 seconds (or whatever you set in CellLog8).  If you are not logging, it will still open the channel but have nothing to receive.  When you then go to the logfiles menu on the CellLog8 and select "transmit", the file will be broadcast on the serial port and LogView will be listening for it and will save it in the PC memory (which you can then save to disk).

If you do not put the "Automatic start recording" option on then you have to press the record button on the LogView panel BEFORE hitting "Transmit" on the CellLog8 (otherwise LogView won't be listening for the broadcast).

Transmission of a big log file (say 30,000 entries) can take a few minutes!  You will see NOTHING on LogView while this is happening (apart from the green communication lights on LogView flashing).  You WILL see CellLog8 counting though the log entries to show progress of the BROADCAST.

When the transmission is completed, the CellLog8s will beep and then LogView will draw the graph of the data received.  At this point the data is only in memory and you should save the data from the File > Save As menu option in LogView before messing about with the data.

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