The Beckhoff MX-System: New automation construction kit replaces the control cabinet

The robust baseplate, consisting of an aluminum profile, forms the basis of the MX-System as a rear panel. It offers standardized plug-in connections onto which the various function modules of the MX-System can simply be plugged and then screwed in place using captive screws located in the modules.

The baseplate can vary in size and can contain up to three rows, each with a maximum of 24 slots. Behind each slot row there is a backplane that distributes different voltages and EtherCAT as communication bus among the slots, depending on the type. Thus, the baseplate can be adapted almost arbitrarily to the respective requirements of the machine.

A distinction is made between two types of backplanes and thus slots: Data backplanes with MX-C slots, via which the modules are supplied with 24 V DC or 48 V DC and EtherCAT, and power backplanes with MX-P slots, via which the mains voltage (3-phase + N 400 V…480 V) and the DC link bus (maximum 848 V DC) are distributed. An MX-P slot can be loaded with a maximum of 35 A, while the underlying power backplane can provide a maximum of 63 A.

The respective MX modules can also have different sizes depending on their function. For example, a simple MX I/O module will typically fit in a single MX-C slot to provide power and communications, while larger drive modules may go across multiple slot rows, as these modules require a plug-in connection to a MX-C slot for communications and MX-P slot for power. The function modules can also vary in width and can be up to 3 slots wide. For example, with large power modules, the power can be fed in parallel via two MX-P slots.

Since each function module plugged onto the MX baseplate is also an EtherCAT device, comprehensive diagnostics are available for the entire MX-System. Furthermore, the MX baseplate has a complete housekeeping system that permanently monitors environmental parameters such as temperature.

The MX baseplate can be easily attached directly to the machine using screw connections and can thus be integrated into the machine installation space both visually and functionally.

To supply the MX-System with power, power feed modules are provided for the mains connection. Each of these has its own fuse, which can be replaced when the system is in a de-energized state. To reach this state, the power supply modules have a load-break switch as a main switch, so that the MX-System can also be de-energized under load. The main switch can also be locked in the 0 position. This makes the MX-System easy and safe to maintain.

The power supply modules feed the three phases as well as the neutral conductor of the mains voltage into the backplane; the respective function modules are in turn supplied with the required voltage via the MX-P slots. The power supply modules are available in different sizes for 16 A, 32 A or 63 A.

If fed in, the three-phase mains voltage and the DC link voltage are distributed over the entire power backplane. The outgoing connectors of the respective MX slots can supply the plugged-in modules with both voltages and are loadable with up to 35 A. The entire backplane can be loaded with up to 63 A.

In addition, the 400 V AC and 600 V DC voltages can be fed out of the MX-System with the aid of power feeder modules and fed into other MX baseplate stations, for example. Cascaded decentralized systems can thus be set up without any problems. The power feeders record the currents and have appropriate fuses to reduce the conductor cross-sections.

All function modules that use the 400 V AC fuse the voltages within the respective module. The 600 V DC modules are protected by electronic monitoring in the corresponding backplane modules.

The extra-low voltages 24 V DC and 48 V DC are also fed into the modules via the corresponding backplane and the MX-C slots. For this purpose, the voltage can be fed directly into the backplane via a filter module or, alternatively, a power supply module can be plugged into the system, which generates the extra-low voltage directly from the 400 V AC or 600 V DC of the 2-row MX baseplate. In addition, the power supply modules and bus coupler modules directly contain a power supply unit and thus supply the data backplane with 24 V DC and 48 V DC respectively. A maximum of 20 A can be supplied to the backplane via an MX-C slot. By connecting power supplies in parallel, larger currents of up to 30 A can also be distributed across the backplane. The 24 V DC or 48 V DC are fused within the function modules to enable the cross-section of the outgoing lines to be reduced here as well.

EtherCAT also runs as a fieldbus in the data backplane and is routed to the modules via the MX-C slots. Thanks to the proven, robust and fast EtherCAT communication, even the most complicated machines can be implemented using the MX-System and cycle times << 1 ms can be achieved. Furthermore, functions such as hot-swap are directly integrated, so that modules can be exchanged or additional subsystems or MX baseplate stations can be connected even during operation.

Since each function module is thus automatically an EtherCAT device, comprehensive diagnostic data is available for all modules and thus for the entire MX-System, which can be conveniently viewed and analyzed on the central controller.

The consistent use of EtherCAT in each MX-C slot also tends to make the proven and powerful TwinSAFE Safety functionalities available to each module. Accordingly, safe I/O and motion modules with well-known safety functions such as STO/SS1 or Safe Motion are available in the MX-System.

Furthermore, modules such as an IO-Link Class B master also have a safe disconnection of the supply voltages of the actuators.