Connection and disconnection of slaves during operation with EtherCAT Hot Connect
The efficiency of industrial automation systems stands and falls with their uninterrupted operation and high flexibility with regard to dynamic configuration changes. The following example illustrates what this means in practice:
Let's imagine a production plant whose assembly robots have tool changers in order to realize several production processes with one hardware. In terms of industrial communication, a tool change means that slave devices have to be switched on or off during operation. While the network configuration is dynamically adapted, the assembly robot must continue to function without interruption. The master must therefore not cause a system failure due to configuration errors.
To ensure this, the EtherCAT protocol for masters offers the “Hot Connect” functionality, which is explained in more detail below.
With Hot Connect, preconfigured sections of a system can be removed from or added to the data traffic before starting or during operation. These sections are called Hot Connect groups and consist of one or more slaves. The groups are connected or disconnected, for example, by switching the participant on or off or by connecting or disconnecting the communication link. Depending on the type of device, rotary switches or displays are usually used for this purpose.
If the master detects a new group at a point in the topology intended for Hot Connect, it initially attempts to identify all slaves via their unique address. Addressing is usually carried out via two different registers or access mechanisms - the second station alias or via an ID. These are assigned to the slaves during the initial configuration. As soon as the master has identified the slaves in a hot connect group, it activates them, puts them into operation and starts the delivery of data frames.
Advantages of Hot Connect
Dynamic configuration:
Hot Connect enables the system to adapt to changes without interrupting operation. For example, this could be machines in a production line that need to use different tools with embedded EtherCAT devices. With EtherCAT Hot Connect, these devices can be switched on and off during operation.
Seamless integration:
The EtherCAT network reconfigures itself automatically. When a new device is connected or removed, the master node reads the updated network configuration and adjusts the communication times and data exchange routines accordingly.
High availability:
Hot Connect increases the robustness and availability of the system. In an industrial facility, minimizing downtime is critical. Hot Connect supports maintenance processes and upgrades without interruption, resulting in higher operational efficiency.
Hilscher's master firmware for EtherCAT, which can be loaded onto any master-capable netX chip, always has the Hot Connect feature on board. This means that every master-capable EtherCAT module, such as corresponding cifX PC cards or embedded modules, can also use this feature.
When configuring a master using a configuration tool such as “Communication Studio with Master DTM”, networks and their topology can be created quickly and easily using a clear graphical user interface. Slaves can be declared as Hot Connect and assigned to their corresponding group. The tool also shows which addressing mechanisms a device supports and allows them to be parameterized.
These Hilscher products support EtherCAT Hot Connect:
Network controller for fieldbus and Real-Time Ethernet (master and slave)
Loadable Firmware EtherCAT Master
PC card PCI Express - Real-Time Ethernet
Communication for PC-based automation
From turn-key products to highly integrated solutions and complementary software, Hilscher is your partner for industrial communication. Get an overview of how we can help you take the networking of your machines to a whole new level!
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