Spearheading Synchronisation with Actuators

SIPOS Aktorik (Germany), supplier of standard and specialist actuators, has addressed synchronisation of valve stems. Traditionally, a mechanical process links two gearboxes to one actuator and this approach is frequently satisfactory. However, stems can be a considerable distance apart and this automation issue has been addressed by SIPOS.

The company’s synchronisation solution is achieved without the need for special programming in an external PLC. A master actuator receives its control signal from the PLC (OPEN/CLOSE, PROFIBUS or analog): from there, the setpoint is transmitted to the slaves via a 4-20 mA loop ensuring that control information is received simultaneously.

To ensure optimal performance, actuator operation is monitored internally at two levels. At the first level, if deviation is larger than a programmable value, then a ‘slow’ signal is generated and at the second level, a ‘stop’ signal is transmitted.

SIPOS advises that, unless these measures are taken, mechanical problems due to preprogrammed one-sided loads can occur, such as canted penstocks or twisted stems, which are costly and time consuming to resolve. Additionally, if site conditions mean that valve stems cannot be coupled mechanically, then issues can extend beyond synchronisation of the two stems to include operation of more than one valve or gate.