Hybrid Plug-in Connectors for Motor Control Systems

Motor control systems are increasingly becoming more compact while their use is growing with applications in Industry 4.0 and Industrial Internet of Things (IIoT). In fact, motor control systems are prevalent in varied industries like food and beverages, material handling, and robotics. However, as the size of the controller shrinks, designers are facing a new challenge—routing power and signal easily and cost-effectively—while ensuring operator safety and electromagnetic compatibility.

One can use advanced open source interfaces to connect both power and data signals with a single compact connector. Although this does simplify connectivity, the quality, design, and performance of the connector become critical to ensure signal integrity, EMC, and compliance with IP20 requirements.

Designers have moved to Hiperface DSL and SCS open Link, open-source interfaces, to allow the same connector to carry both power and data. This not only saves space but also lowers the cost and simplifies the design of high-performance motor controllers.

The communicating cable has two shielded wires for bi-directional communication based on RS-485, and other wires for encoder power, motor power, and motor brake controls. There are three elements—a three-phase power supply cable, a shielded motor brake cable, a shielded data pair for digital data transfer—enclosed within a shielded cable.

The Hiperface DSL offers a data transmission rate of 9.375 MBaud, over a cable distance of up to 100 meters between the motor controller and the motor. It is possible to transmit data on the cable in two ways—cyclically, given signal and noise conditions, or synchronously with the controller clock.

The motor feedback interface design of the SCS open Link system can supply bidirectional data between the motor and controller. This includes encoder data at rates up to 10 MBaud. It is possible to use two or four-wire implementation. This link is optimized for Industry 4.0, and especially for emerging IIoT solutions, including motor condition monitoring and predictive maintenance.

For SCS open Link and Hiperface DSL to operate reliably, the connection needs optimum shielding between the motor/encoder and its drive. The number of interfaces reduces with the use of plug-in connectors and connection terminals. It is also important to have unbroken shielded cables between the motor/encoder and the drive. However, as the drive connector is non-standard, designers must be careful when designing their own connectors for meeting performance requirements.

OMNIMATE Power Hybrid connectors are an alternative to the SCS open Link and Hiperface DSL. These are a three-in-one solution providing signal, power, and EMC features that implement the SCS open Link and Hiperface DSL protocols. Moreover, the hybrid connectors save space on the motor drive printed circuit board and in the controller cabinet.

The hybrid connectors are available in several configurations. These include six-, seven-, eight-, and nine-position connections. They include power and signal contacts with push-in wire connections. The pitch is 7.62 mm, conforming to the IEC 61800-5-1 and UL 1059 Class C 600 V standards. Several practical design features in the connectors provide high reliability. For instance, the adequate separation between encoder and power connections ensures minimum EMC.