Which system allows for query and configuration changes over a network for PLCs?

Modbus is a communication protocol designed specifically for industrial automation applications. It allows for query and configuration changes over a network, making it particularly suitable for programmable logic controllers (PLCs). This protocol uses a master/slave architecture, where a master device can send requests to slave devices, allowing operators to monitor and control various aspects of the PLCs remotely.

One of Modbus's strengths is its simplicity and effectiveness in enabling communication between devices on the factory floor. Its widespread adoption in industrial settings means that many PLCs come with native support for Modbus, providing a standardized method for data exchange and device configuration.

By enabling real-time data access and command execution over a network, Modbus plays a crucial role in the interoperability of different devices within an industrial control system, facilitating efficient monitoring and operations. This capability is essential in modern manufacturing environments, where rapid response to changes and issues is vital.