Category: Connectivity

Scales and balances become more useful when they are connected to other equipment such as a PC for data acquisition, a PLC, data logger, printer, etc.

On this page you will find all articles about the connection of scales to other devices.

Using verified Ohaus SJX scales with our software

Most class I and II weighing instruments use what is called an “auxiliary indicating device” with a “differentiated scale division”1: On the display, the final digit or digits are visually distinct from the others. This is also the case with Ohaus SJX scales that have been verified (e.g. the SJX6201M):

Note how the scale division (d) is one tenth of the verification scale division (e) when weighing in g

This digit is enclosed in square brackets when the weight is sent over one of the optional interfaces (such as RS-232, USB, or Ethernet). Example:

   1234.[5]     g

By default, our software does not capture a digit that comes after a non-numeric character. This can be easily fixed in two steps. We’ll use screenshots from Simple Data Logger as an example, but the procedure is basically the same for our 232key virtual keyboard wedge software2.

1. Change the regular expression used to capture the weight

In the Input tab, click the Customize button and replace the regular expression with the following one:

(-*[0-9]*\.?[0-9]*\[[0-9]+)

This will ensure that the opening square bracket and the last digit are also captured (shown in blue in the Event Log):

Remove the bracket

The string we’ve now captured is not a number because it contains a bracket. Writing it to a file like this would make things complicated when processing the data later.

Fortunately, you can easily remove the bracket: Go to the Process tab, check Enable Editing, and enter the opening square bracket “[” in the Remove characters field:

SDL will now properly write the complete weight as a number to the CSV file, which can be opened in Excel or other programs:

Important: If you are utilizing our software in connection with a verified scale, please ensure that such usage is compliant with the regulations and requirements of your local jurisdiction.

1: See OIML R76 (PDF) for further information
2: For an example that uses 232key, see this article

A GX16 connector that does not fail

If you’re working in the weighing industry, you’ve probably come across the GX16 connector:

GX16 connector
Typical GX16 connector (male)

This circular connector is named after its M16 thread and can have up to 8 pins. While it is frequently referred to as an “aviation connector”, I sincerely hope that it is not actually used in aircraft, as I’ve seen many of these connectors fail. Their tiny screws are prone to coming loose, which renders the strain relief useless. Then it’s only a matter of time before the cable is pulled too hard and the wires detach.

What does it take to make a reliable GX16 connector?

This is the Ohaus Catapult 5000 scale:

Ohaus Catapult 5000 scale

It uses an overmolded GX16 connector to connect the platform to the indicator:

Ohaus Catapult 5000 scale indicator

We’ve sold hundreds of these scales and never had an issue with them that was caused by the connectors. This is due to the extensive work that Ohaus put into making them, as demonstrated by the photos below. Apologies for the photo quality, I didn’t take them in our photo studio and it shows.

Completely disassembled GX16 connector
Disassembly of the overmolded Ohaus Catapult 5000 GX16 connector (female) reveals that it contains a complete regular connector, including the metal backshell
The screws of the strain relief are secured with heat shrink tubing
The connector is completely filled
After removal of some material
Further material removal reveals that heat shrink sleeves were used after soldering

Further info

A&D EK-i/EW-i scales: Changing the data transmission mode

The scales are equipped with an RS-232 interface and can be connected to a PC for data acquisition (if necessary via an adapter from RS-232 to USB). They are known as “Everest EK/EW compact balances” in the US.

Applications such as the following can be used to capture the weight:

  • Simple Data Logger (writes the weight to a file with date and time),
  • 232key (enters the weight as simulated keystrokes directly into another application),
  • WinCT (a collection of 3 applications from A&D),
  • LabVIEW,
  • any terminal software (useful for testing data transmission).

Data transmission modes

EK-i and EW-i scales support the following transmission modes:

  • Prt 0 – stream mode: continuous transmission of weight with approx. 10 values/s,
  • Prt 1 – PRINT key (default setting): transmission when pressing the PRINT key on the scale,
  • Prt 2 – auto-print A (positive values only): automatic single transmission when the weight is stable (return to zero required before next transmission),
  • Prt 3 – auto-print B (positive and negative values): automatic single transmission when the weight is stable (return to zero required before next transmission),
  • Prt 4 – command mode only: request-response mode, the computer sends a command to the scale and it responds with the weight value.

Notes:

  • The display flashes briefly (in Prt 1, 2 and 3) to confirm the data output.
  • Commands from a connected computer can be sent in all modes.
  • The PRINT key is active in all modes except Prt 4.
  • There is no interval mode. If you want to capture the weight in certain intervals (e.g every minute), you need a software that supports polling with a timer (or you could set the scale to stream mode and discard most values).

These data output modes can be found in the Func class of the scales’ menu:

Excerpt from the user manual (see link below)

Changing the transmission mode

  1. Turn on the scale.
  2. Press and hold the SAMPLE key until the scale displays “P-3.00” (or a similar value). The scale shows “Func” next.
  3. Press the PRINT key to enter the function settings menu. The first setting “PoFF” is displayed.
  4. Press the SAMPLE key 8 times to enter the “Prt” setting. By default, “Prt 1” is set.
  5. Set “Prt” to the desired value by pressing the RE-ZERO key (see description above).
  6. Confirm the setting with PRINT. The balance displays “End” briefly and then “CP Hi”.
  7. Restart the scale by pressing the MODE key.

Further information