Joined: 13 Mar 2007
Location: Netherlands and Kazakhstan
|Mar 26, 2007 2:52 pm
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.