Home / Industrial Scale API: REST, JSON Output & Remote Control

Which devices connect to the scale?

The scale and your receiving computer connect through an Ethernet switch or Wi-Fi access point on a reachable local network. UpScale hosts the REST API and can also send JSON pushes. Your PC or local server runs the requesting or receiving software; an external backend is optional.

GET weight retrieval

Your application requests a reading from UpScale. The indicator replies with JSON.

Scale-originated JSON push

UpScale POSTs JSON to your receiver periodically or through PRINT.

Separate remote controls

Your application POSTs supported zero, tare or other commands to UpScale.

A local collection workflow does not require an internet connection. Your application handles any backend forwarding and its authentication. ScaleAPIMonitor is a local JSON-push receiver demonstration with separate scale controls; a custom GET client can run on the same type of computer.

How do GET requests and JSON push differ?

GET weight retrieval starts with your application requesting a reading from UpScale, either on demand or through polling. JSON push starts with the scale sending an HTTP POST to a configured receiver periodically or through PRINT. Both deliver JSON weight data. Remote controls are separate POST requests sent to the indicator.

The addresses and ports in these scenarios are examples. Use the indicator’s configured API endpoint for GET requests and your application’s reachable receiving URL for push delivery. Set up these two endpoints before testing. Remote zero/tare commands are POST requests to the indicator, separate from POST delivery to your receiver.

A shipping application can request a package weight when an operator saves a shipment. A tank-monitoring application can receive periodic readings. An operator can use PRINT to send the reading associated with a particular weighing step. These are example workflows; the receiving application handles its own records and business rules.

For the application-level workflow and practical weighing uses, see web application weight data collection.

Set up the scale and receiving application

Begin with an UpScale-equipped scale configured for the API option and Ethernet or Wi-Fi TCP/IP. Record the indicator’s IP address and configured HTTP API port. For push delivery, also identify the receiving computer’s reachable network address, listening port and URL path. The indicator and receiver have separate network endpoints.

The addresses and port numbers above are examples. Use the port configured on your indicator. The receiver’s port is configured in your application. A scale cannot send to the PC’s localhost address; give it the PC’s network address. Keep the devices on a trusted network with the required connections permitted.

Read weight through the weighing scale REST API

Send a GET request to the indicator’s weight resource to read its current weighing state as JSON. The response identifies the displayed weight, unit, tare and gross/net mode, with platform and stability information where provided. Field names are case-sensitive, and the meaning of Weight depends on the Gross mode flag.

curl "http://192.168.1.141:8080/api/1.0/weight"

Example response:

{"Platform":1,"Unit":"lb","Weight":128.4,"Tare":2.0,"Gross":false,"Stable":true}

In this constructed example, the net reading is 128.4 lb and tare is 2.0 lb, so gross weight is 130.4 lb. A timestamp or device name added by your receiving application describes that application’s record; it is separate from the indicator’s documented response.

Receive periodic or PRINT-triggered JSON

Web API Push sends weighing data from UpScale to an application that accepts HTTP POST requests with JSON bodies. Configure the receiving URL on the indicator and select periodic or PRINT-triggered delivery for the workflow. The receiver parses the reading, validates the fields and decides how to store or use it.

1. Start your receiver on a computer reachable from the scale.
2. Enter that receiver’s full URL in UpScale’s Web API Push configuration, including its listening port and path.
3. Use the JSON output and HTTP POST delivery configuration.
4. Select the required delivery trigger: periodic readings or PRINT.
5. Place an item on the scale, wait for the configured interval or press PRINT, and inspect the JSON received by the application.

A POST to your receiver delivers data. To operate the scale, send a separate supported REST command to the indicator. For ERP systems such as NetSuite, a receiving bridge can map the weighing data and perform the ERP’s authentication and record-writing steps.

Use remote zero/tare control

Remote commands call the indicator’s REST API with HTTP POST. They reproduce supported button actions such as ZERO and TARE while keeping data delivery separate. The examples below act on the current displayed platform. Unit and gross/net commands toggle state; applications can read the resulting state back to verify the change.

curl -X POST "http://192.168.1.141:8080/api/1.0/button/tare/click"
curl -X POST "http://192.168.1.141:8080/api/1.0/button/zero/click"

Use POST for these commands; entering the command address in a browser normally sends GET. The REST HTTP API reference describes the read resources and button actions.

Try ScaleAPIMonitor with a scale or demonstration

ScaleAPIMonitor is Arlyn’s free, open-source Python tool for viewing incoming JSON and testing REST controls. It runs a local web dashboard, accepts scale pushes and separately calls the indicator for button commands. Its demonstration mode supplies simulated readings and a mock scale API so you can explore the workflow without hardware.

1. Install Python 3.8 or newer and download ScaleAPIMonitor. Extract the files and open a terminal in that folder.
2. Start the receiver with the command below, or use run.bat on Windows.
3. Open http://localhost:8080/ on that PC and copy the dashboard’s push URL into the scale. Use the receiver’s network address, not localhost.
4. In the dashboard’s Scale control panel, enter the indicator’s IP address and configured API port, then select Test connection.
5. Trigger a push and inspect the reading. Test a supported control when the weighing operation permits it. Restrict access to the trusted local network; the monitor dashboard has no login.

python scale_push_monitor.py

# Explore simulated readings and controls without a physical scale:
python scale_push_monitor.py --demo

Allow the receiver’s selected port on the trusted local network so the scale can reach it. Monitor-only routes such as /api/state, /events and /api/scale belong to the PC program. They are not additional indicator endpoints. See the monitor user guide and integration examples for application code.

Frequently Asked Questions

Choose an API-equipped scale

For a new Arlyn scale, select the UpScale touchscreen indicator and the API option with Ethernet or Wi-Fi on the Configure and Buy page. Use Scale Options to compare communications, then use this guide to connect the scale to your application, receiving service or local test computer.

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