Modbus in the browser

Sending alarms with Modbus: Master writes to the register - Web-IO sends e-mail

Equipment controlled via Modbus is mostly found in closed systems. The equipment is monitored using a host computer on which special or critical operating states are displayed and signaled.

The new generation of Web-IO Boxes provides the Modbus master, depending on the model, with up to 12 virtual registers (coils). Setting these registers does not change anything in the real IO status of the Web-IO, but an internal alarm is triggered. When alarms are present the Web-IO informs the user depending on the configuration by e-mail, SNMP trap or syslog. Logging the alarms via FTP is also possible.

In this way the Modbus master can even signal operating states across different locations.

Modbus in the browser: The Web-IO brings process data written by the master into the browser

Modbus systems are generally monitored using host computers on which specially adapted visualization software is installed. This limits the number of workstations which allow viewing into the system.

The new generation of Web-IO Boxes opens the way to modern web technologies for Modbus.

The Web-IO provides 128 bytes of freely writable memory in the form of virtual registers. The Modbus master can write any desired amount of process data to these registers. Using simple HTTP requests these process data can be read out by Web applications and displayed in the browser.

A table format display of the register contents is already implemented in the Web-IOs. Using JavaScript, AJAX or PHP the process data can be post-processed and graphically displayed.

Switching with Modbus TCP: Access to digital inputs, outputs and counters

The new Web-IO generation enables reading of input/output status and counters and, depending on the model, switching of up to 12 outputs.

Modbus and Web: Combine existing systems with web services

With Modbus TCP the W&T Web-IO boxes now support an additional protocol from automation technology.
Integrating into existing systems is child’s play thanks to the standardized Modbus protocol.