Service RPC

Who it’s for

Engineers operating devices behind a ThingsBoard IoT Gateway who need to send a command through to the device itself — writing a Modbus register, calling an OPC-UA method, prompting a poll. The command has to reach a device the platform cannot address directly, and the gateway is the route.

What it does

The Service RPC widget sends RPC requests through the gateway to the devices connected behind it, or to the gateway’s own connectors. Pointed at a gateway, it lets a service-level command be composed and dispatched, with the gateway translating it into the connector’s own protocol.

• Commands reach devices the platform cannot address — the gateway performs the protocol translation.
• The widget can target either a connected device or a connector, which is the difference between commanding equipment and reconfiguring the route to it.
• The response comes back through the same path, so a two-way call’s result is visible.
• Access follows the dashboard, so the ability to command behind the gateway is granted by dashboard permissions.
• The Service RPC widget requires the gateway to support the command for the connector in question; an unsupported request fails at the gateway rather than at the device.

How to set up

Data keys

The Service RPC widget takes no data keys — the request is composed in the widget.

Method	Direction	Parameters	Sent when
Gateway service method	Two-way (request-response)	The composed request, translated by the gateway’s connector	On each send

Target

Setting	Default	Effect
Connector mode	Off	Targets a connected device; turn on to address a gateway connector instead

Point the datasource at the gateway device, not at the device behind it. The gateway is the entity the platform can reach, and it is the gateway that resolves which connected device the command is for.

How to customize

• To address a connector rather than a device — turn on connector mode, which changes what the request is aimed at.

Tips

• Check the connector’s documentation for which service commands it implements before building a dashboard around them. Support varies by protocol, and a request the gateway does not recognize fails in a way that looks like a device problem.
• Keep this widget on an engineering dashboard rather than an operational one. Commands sent through a gateway can reconfigure the route as well as the equipment, and that is not a distinction an operator should have to make under pressure.