Computer Interfacing
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RS232 output from a scale >> USB stick (without PC)

Looking for low cost flash data storage solution from RS232


 

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jacob
New User



Joined: 25 Mar 2007
Posts: 1
Location: The Netherlands - Zaltbommel

Mar 25, 2007 5:19 pm

I have a weighing indicator with RS 232 output to make print outs on a printer -- or send to a PC for storage

I need to have now a ( cheap ) USB stick to store the weihing data
Is there a converter from RS 232 >> USB ?? ---- on both ends of the line there is no PC or laptop !!

look forward to you input
rgds Jacob blom - Ravas
lammert
Site Admin



Joined: 13 Mar 2007
Posts: 145
Location: Netherlands and Kazakhstan

Mar 26, 2007 2:52 pm

Hello Jacob,

First of all welcome to the Computer Interfacing forums!

There are RS232 to USB converters, but they normally only work when connected with a computer where the drivers for the converter are loaded. These drivers are necessary to provide the protocol layer to communicate over USB. In your situation you don't want to use a computer in between the RS232 weighing device and USB flash memory. In that situation there is no processor to perform the communication and protocol conversion so it will not be possible to store the data from the RS232 port to the flash memory. Unfortunately I do not know of any intelligent RS232 to USB converters that you can use in your situation.

There is however a way to solve the problem with a small computer device like a PDA (Pocket PC etc). Most PDA's have the possibility to store data on low-cost flash memories of SD or Compact Flash type. Many PDA's have also an RS232 port. Although most PDA's have a USB port too, that port is normally only used as a slave connection to a PC.

My recommendation in your application is to use a Pocket PC device that connects over the RS232 port to the weighing system, and stores the data on a Compact Flash or SD flash drive. Internal and external flash device readers for PCs can be bought for about EUR 15 at computer stores, so after the data is stored on the flash card, it can easily be transferred to a PC without use of the Pocket PC.

Lammert

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