Modbus TCP

Modbus TCP is a fieldbus based on the application layer of Modbus with which the data are transferred via standard Ethernet (TCP/IP) (unlike the serial transfer used with Modbus RTU and ASCII).

Unlike most other Ethernet-based fieldbuses, such as EtherCAT or PROFINET, Modbus TCP requires no fieldbus-specific hardware but instead works with normal network cards and routers, which are used by the million. In addition to the price advantage, motor controllers with Modbus TCP can thereby be controlled not only using PLCs but also very easily via standard PCs, as almost every programming language offers a library for TCP/IP communication. Moreover, special libraries for Modbus TCP also frequently already exist.

The use of standard hardware also leads to a disadvantage for Modbus TCP, however: unlike CAN or EtherCAT, Modbus is not, for example, suitable for realtime applications that require an accurately timed synchronization of multiple axes. Transfer via Ethernet is fast but not deterministic, i.e., the transfer times may fluctuate strongly, particularly in larger networks. Modbus TCP is, however, very well suited for applications in which multiple motors are controlled independently of one another, e.g., during format adjustments. It is also possible to start multiple motors at the same time via digital inputs and to simultaneously use Modbus TCP for parameterization and diagnosis.

Nanotec offers motor controllers as well as brushless DC motors and stepper motors with integrated controller and Modbus TCP interface.