Scale

Service for reading data from FedEx protocol Scales. It has been tested with Mettler Toledo PS scales, but should work for any scale compatible with the FedEx protocol. More protocol support may eventually be added

Installation

1. Clone the repo
2. mix deps.get
3. iex -S mix

Configuration of Scale

Currently Scales need to be configured with the following settings

Checking/Changing Mettler Toledo scale settings

These instructions are for Mettler Toledo PS scales.

1. Press and hold the Units (two circular arrows) symbol for 10 seconds, until the scale displays SETuP?
2. Press the Units key until BAud is shown on the display
3. Press the Units (two arrows pointing to a 0) key to view the baud. If it is not at 9600, press the Zero button until it reads 9600.
4. Press the Units key to view the ASCII bit setting. If its not at 8, press the Zero button until it reads 8.
5. Press the Units key to view the Parity setting. If its not at None, press the Zero button until it reads None.
6. Press the Units key to view the Stop Bit setting. If its not at 1, press the Zero button until it reads 1.
7. Press the Units key to view the Protocol setting. If its not at Proto1 (FedEx), press the Zero button until it reads Proto1.
8. Press the Units key until END is displayed. Press the Zero key until Save is displayed. Press the Units key to accept the changes and reboot the scale

Connecting a scale to a computer

Scales can be connected to a computer using either USB or Serial. A Serial to USB converter may be used.

If you use a Serial to USB converter, make sure you have the proper drivers. Prolific (a serial port chipset) based drivers are more prone to issues than FTDI drivers. Mac OS and many other systems come with FTDI drivers built in; Prolific drivers can be installed on MacOS via Homebrew Cask

brew cask install prolific-pl2303

Once this is installed, you need to find the configured serial port for your scale. Odds are that its at /dev/cu.usbserial, but it may not be. Look in ls /dev/ to find it. It will likely mention usb or serial, not just a plain TTY.

Once you have the serial port, edit config.exs and you're ready to go.

Dummy Scale and Testing

A dummy scale is included for your testing convenience. To use it you will need to use a loopback serial port, such as tty0tty (linux), com0com (windows), or socat (macOS)

Setting up a loopback serial interface is not difficult, but Circuits.UART has a better guide available.

Once you have a virtual port running, edit the config.exs file. Comment out the "real" serial port, uncomment the dummy: true line and lines containing configuration for the loopback serial interface.