AUMA actuators’ advancements to Modbus loop capability for valve automation has benefited data transfer speed and safety in the power industry. AUMA has reported that the Modbus initiative triples the maximum possible data transfer rate, and significantly reduces the feedback time of actuators in the loop, which improves the overall response time of the system. AUMA has supplied the industry with fieldbus enabled actuators for over 15 years and Modbus looped systems for over five years. The company’s latest Modbus systems comprise a SIMA master station with up to 247 actuators, suitable for installations where long cable distances are involved. The looped solution is capable of supporting conventional copper cable lengths of just under 300km and uses the Modbus RTU protocol based on RS-485. Additionally, if the redundant loop is interrupted, data communication to all installed actuators is maintained without any restrictions. An automatic commissioning feature for the new system from AUMA reduces start-up times and configuration errors.
When the SIMA master station is switched on after completion of the wiring, it can determine the number of actuators connected, automatically assign the slave addresses of actuators and set the desired baud rate. As a result, manual setting of the communication parameters at each actuator is no longer required, which leads to considerable time savings during commissioning. Communication problems, such as slave addresses assigned twice or transmission rates set incorrectly, are also avoided.