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Communication Types

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Communication Types

Two types of communication are available for the interaction between the operator device and the endpoint (e.g., PLC control). Gateway communication offers features such as push notifications and an internet connection. In direct communication, the operator device communicates directly with the endpoint.

Direct or Gateway Communication

When creating an HMI operator app, the question quickly arises whether direct communication between the operator device and the endpoints is sufficient or whether the Unified-E App Manager as a server, i.e., gateway communication, is required.

For the following HMI operator app requirements, gateway communication with the Unified-E App Manager is the right solution:

  • The plant or machine should be operated simultaneously with multiple operator devices.
  • The plant should be operated or monitored via the internet on a smartphone or tablet.
  • Central functions such as message logging or data point connections should remain active even when the operator device is turned off.

Direct Communication

In direct communication, the operator device is in the same network as the controller. The data necessary for visualization is transferred directly from the controller to the operator device. No additional software or gateway server is required.

The operator app is created using the "Unified-E App Designer" software and then installed on the operator device using the Unified-E App Client program or the "Unified-E" app from the store.

Direct Communication

In principle, a connection between the operator device and the endpoint via the Internet is possible in direct communication. For example, the operator device can securely access an OPC UA server directly using OPC UA, or a VPN can ensure that operator devices and endpoints are in the same network.

Advantages Compared to Gateway Communication

  • Unified-E App Manager not required
  • No PC required for operation, Android or iOS operator device is sufficient
  • One-time license, as no online services are used

Use Cases

  • Stationary HMI
  • Remote control with a smartphone
  • Mobile maintenance
  • Mobile calibration and setup of machines

Supported Endpoints and Protocols

For Windows operator devices, all endpoint adapters (protocols) available from Unified-E are supported.
For the Android and iOS platforms, only the following protocols are supported:

  • OPC UA
  • Modbus
  • Siemens S7
  • Allen Bradley

Licensing

A direct license is required per operator device.

The prices can be found under Licenses -> Direct License .

Gateway Communication

In gateway communication, data exchange between the operator device and the plant runs through a Windows computer. With the "Unified-E App Manager" software, the computer becomes the gateway and is responsible for encryption and user management. The app manager is ultimately responsible for data exchange and forwards app requests to the respective endpoints. The gateway PC (app manager) is usually on-site with the customer and must have access to the endpoints of the operator app - usually via a local network.

Gateway Communication

The following variants of gateway communication are possible between the gateway and the operator device:

Internet Firewall-Friendly

The smartphone communicates with the gateway indirectly using a relay messaging service via the Internet. Advantage: The gateway does not have to accept incoming HTTPS connection requests, so additional configurations on the router or firewall are not necessary.

Internet Direct

The smartphone communicates directly with the gateway, which is connected to both the Internet and the local (production) network. This type of communication requires setting up port forwarding on the router or firewall.

Local Network (Offline)

In this type of communication, it is assumed that the gateway PC is not connected to the Internet. Therefore, there are some limitations: Local push notifications are only supported on Android devices, and licensing is done with an offline license key.

Advantages Compared to Direct Communication

  • Additional endpoint adapters available for the integration of production data (SQL, JSON)
  • Firewall-friendly, encrypted communication via the Internet, no port forwarding or fixed IP address required
  • Sending messages via push notifications to smartphones

Use Cases

  • Remote control with the smartphone via the Internet
  • Stationary HMI with central data storage and central functions such as data point connections
  • Plant operation with multiple operator devices
  • Dashboards

Licensing

Licensing is done on the gateway PC. When purchasing a license, the number of registered control devices determines the price. The use of push notifications and online services is optional. If these services are utilized, annual service fees will apply.

The prices can be found under Licenses -> Gateway Licenses .

And this is how it continues...

Various endpoint adapters are available for communication between the operator device and the endpoint. During communication, the necessary data point values are read for visualization or data point values are set during active operation. Both standard protocols and protocols of established PLC manufacturers are supported.

Learn more