Hands-on Modbus Cloud Connect – Instant Read & Instant Write via Narrowband-IoT

There are many solutions for remote monitoring. Many gateways can read and send measured values. Some can write parameters. But what can you do if parameters spontaneously need to be changed remotely or if a new measured value is required that is normally transmitted only once a week?

Daniel Schmitz — Sales Engineer IoT

July 4, 2023

About the blog article series:

Modbus is a data communications protocol and has become a de facto standard protocol to connect industrial electronic devices. But how could those devices become part of the internet of things and what use cases could be developed? With this series of blog articles, we would like to give answers, ideas, suggestions, and helpful hints. To demonstrate how easy, it is to bridge the gap between devices and IT/cloud infrastructure by using Modbus Cloud Connect.

Scenario / Example

Your company is an established service contractor in building technology. Among other things, heating systems are maintained and operated and they are distributed nationwide. Your customer (e.g., a retirement home) reports that the heating is not getting warm enough. The supply temperature is normally transmitted once a week and was last transmitted five days ago. The affected heating system is more than 300 kilometers away from your nearest service technician. The service technician is working to capacity on other projects, and the general shortage of skilled manpower rules out new hires on short notice.

Instant Read / Problem identification

You can remotely request the latest value of the heating system’s supply temperature via the Modbus Cloud Connect gateway on the dashboard of this heating system by simply clicking a button. Here you notice that this value is not the standard value of the last couple of months. Probably this value was changed directly at the heating system.

Thanks to the instant read feature, there is no need to think about all scenarios during the initial operation. The dashboard remains tidy. It is therefore sufficient to receive/send only the measured values at a fixed interval that are important in standard operation settings. This can also mean that values are automatically requested by your backend if, for example, a value of a modbus register exceeds/undercuts a threshold value or an alarm register jumps over. By using the instant read feature, measuring data can be read remotely and ad hoc when necessary.

Instant Write / Problem-solving

By using further features on the dashboard of the heating system, you can change the supply temperature. Here you enter the new value, which is again transferred to the system by clicking a button via the Modbus Cloud Connect gateway and written there in the specific modbus register.

Modbus Cloud Connect provides an instant write function. This can be used directly in the self-service-portal or via HTTP or MQTT. With the instant write function, the registers of the connected actuators can be changed ad hoc. Thus, registers can be accessed quickly and easily, even if they have not been configured in the dashboard beforehand.

Simply easy

Both instant read and instant write are very useful features for configuring modbus slaves. Especially if you want to connect an unknown modbus slave, the documentation is sometimes not complete. Sometimes modbus slaves have to be configured first so that the parameters, like baud rate, parity, and number of stop bits, are equal to those of the other connected modbus slaves. Instant write is a very helpful feature for this.

Modbus Cloud Connect makes it easy to use, flexibly connectable and broadly applicable. Your device, directly to the cloud.

Do you have any questions or would you like to start a Modbus Cloud Connect project?

Daniel Schmitz — Sales Engineer IoT

Hi, I'm Daniel. Do you have any questions about Modbus? Feel free to contact me by e-mail.