Reading a ClampMeter which uses Silicon Labs CP2102 USB to UART Bridge

[jetsdream]

Hi there,

As I havent found a satisfactory answer to my problem I´m posting this in the hope that anyone may help.

I´d like to use LabView to read values from a clampmeter. Said clampmeter uses an "readonly" optocoupler which puts out data to an USB cable. Installing the drivers for this device it shows up as an:

Silicon Labs CP210x USB to UART Bridge (COM3)

This is an Virtual Com port which I´d like to interface via LabView. I allready used NI MAX -> VISA Testpanel and I get jiberish data from the device. I know that it is working on 2400 baud using 8 bit; 1 stop bit and no parity.

I used a Serial sniffer to evaluate the raw serial data when using the manufacturer supplied software (which works fine by the way). Even then I only saw data which made no sense.

According to some posts I tried to use a dll-node to communicate to the CP2102 Chipset via dll´s provided by Silicon labs, which didn´t work that well. Even if that should work, how do get serial (readable ASCI) data from the chipset? The Functions provided by these DLL´s seem to only target specific tasks when programming the device as a manufacturer. 

I thought a virtual COM port might easily be read using LabView VISA but this one is realy giving me a hard time. Am I getting something wrong what a  CP210x USB to UART Bridge  is and how it is going to be read?

This is the Chipsets manufactuerer site with the Serial Communcations guide: http://www.silabs.com/products/mcu/pages/usbtouartbridgevcpdrivers.aspx

Any hint on how to read data from this particular chipset is highly appreciated. even a Roadmap on how to approach the probelm would be highly appreciated as I´m realy lost on this one.

Greetings,

Jan

[nyc_(is_out_of_here)]

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@jetsdream wrote:

Even then I only saw data which made no sense.

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Made no sense as compared to what?

If their software works, then try to match it.

[LV_Pro]

As mentioned before "made no sense",  what did you see, with your code or MAX looking at the com port, with the sniffer watching the data talking to the manufacturers program. What make and model clampprobe is it? Do they have a serial comm description? Is it returning ASCII, or is it returning some more "binary" encoding? It may be a matter of reconstructing the returned data into something "man readable". Does what you see with the sniffer agree with what you see otherwise, if so then it is probably a formatting issue, with trying to break out the right blocks.

[Dennis_Knutson]

The format of the data has nothing to do with the usb converter or chipset. It had everything to do with what the vendor of this meter decided. Data is not always presented as readable ASCII. Read the manual for the instrument.

[jetsdream]

I just left the Office. What i saw was a bunch of ASCI strings of 17 Byte lenght. I would have expected a human readable String, separated by some delimeter. Instead the Output looked like:

hh................

as soon as I can I'll make a Screenshot while sniffing the communication with the manufacturer software.

Best regards,
Jan

[jetsdream]

The manual is a badly translated minimalistic paper booklet and of absolute no help regarding the USB communication with the device.
How could I reverse engineer the data structure the manufacturer choose? Is there a way to do do such thing?

[nyc_(is_out_of_here)]

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@jetsdream wrote:
The manual is a badly translated minimalistic paper booklet and of absolute no help regarding the USB communication with the device.
How could I reverse engineer the data structure the manufacturer choose? Is there a way to do do such thing?

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The Silicon Labs device is just a conduit. I find it hard to believe that the clampmeter is just some dumb device.

It has to to format the message that is to be sent through the USB to UART bridge; otherwise, what is the point of the software that you are using.

[LV_Pro]

If you are using the correct baud rate then what you are seeing may well be bytes of data, which quite possibly isn't ASCII, so will not display properly in something that displays man readable data. If you have a piece of LabVIEW code that communicates with the  device, and displays something similar to the "sniffer", then in the output screen, which will be a "string indicator",  right click the indicator (when the program isn't running) and select   " '\ ' Codes display" which will show more raw, non-ASCII data. We may be able to discern more from that. If you can also tell us what is being displayed in the manufacturers program ...

[Dennis_Knutson]

You still have not provided anything that help explain what you need to do. The first piece of missing and essential information would be the make and model of the instrument. The second piece would be the manual. The links to silicon labs and all LabVIEW code is just irrelevant at this point.

[jetsdream]

Well the Model is a PCE-PCM1 or Aktakom ACM-2353. the Manual can be found here : http://www.tmatlantic.com/upload/manuals/ACM-2353_User_Manual.pdf But I guess it will not be of any great help. The device itself seems to be of Chinese Heritage and is obviously sold under different brands.