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If you want to acquire a scale weight directly from your scale (your Truck Scale for example), your scale must be connected to a digital weight indicator and the digital weight indicator must be connected to your computer.

 

This is typically done by connecting the digital weight indicator to a serial port on your computer or an Ethernet connection on a router or network switch.

 

Of course once your scale is connected to your computer you will need software to read the data from the digital weight indicator.

Configuring the digital weight indicator

You'll need a scale and a digital weight indicator. Your digital weight indicator will look something like this:

 

Your indicator must be capable and configured to send weight data continuously (often called streaming or stream mode) or on request (demand mode).

 

While it may be capable, that doesn't mean that it been configured correctly. You may need to have a service technician change your indicators configuration to enable it to send continuously or on request.

 

Sending the data continuously (streaming) is the preferred mode and easiest to debug.

 

Your indicator should not be configured so that the scale operator has to manually cause the indicator to send data (e.g. by pressing the Print key on the indicator front panel).

 

If you are connecting a bench scale or a laboratory balance the digital weight indicator and scale will be usually be a self-contained unit.

Serial port connection

The RS232 serial port remains the most common way to connect your digital weight indicator to your computer.

 

 

 
Using the example and assuming the digital weight indicator transmitting data continuously, the terminal marked TX would be connected to pin 2 on the 9-position connector and the terminal labeled COM would be connected to pin 5.
 
If the indicator can only transmit data on request, the terminal labeled RX needs to be connected to pin 3.

 

 
Most new, off the shelf computers (especially laptops and notebooks) will not have an accessible serial port so you will need a USB-Serial adapter or serial port server. The simplest choice is a USB-Serial adapter.
 

 
 
The other alternative is a Ethernet-based serial port server. If the computer is located more than 15 feet from the digital weight indicator, the serial port server is a good choice. If you need to connect any more than 2 scales to your computer a serial port server is an excellent choice.
 
 

 
If you are unsure about any of the items listed above, contact us.

Connect using Ethernet

It is becoming more common digital weight indicators and electronic bench/platform/lab scales to support Ethernet.

 

If you are using Ethernet (either TCP or UDP), we will assume the indicator has an RJ45 connector and you can use generic off the shelf CAT5 or CAT6 cabling. Select the cable that is appropriate for your network hardware, connect one end to the indicator and one end to the switch or router and you're done.

 

If you must connect the indicator directly to your computer you may need a crossover cable or crossover adapter.

IP address and port number configuration

The critical part of the Ethernet configuration is assigning the indicator an IP address and port number. Then you need to make sure the indicator is on the same IP network as the PC and that the port number is available or your software will be unable to make a connection to the indicator.

 

You should always assign a static IP address to the indicator making sure it's valid for the network your PC is connected to and that it's not in the range that may be used by your networks DHCP server. Don't allow the indicator to be assigned an IP address by DHCP.