Safety Instrumented System
Safety Instrumented System, abbreviated as SIS; also known as Safety Interlocking System. It mainly constitutes the alarm and interlock parts in the factory control system. It triggers alarm actions, adjusts or stops the control based on the detection results in the control system, and is an important component in the automatic control of industrial enterprises.
System Features
(1) Based on IEC61508 as the basic standard, it complies with the safety standards for instruments stipulated by the International Safety Association. (2) It has a wide coverage, high safety, and has self-diagnostic functions, which can detect and prevent potential dangers. (3) The fault-tolerant multiple redundancy system. SIS generally adopts a multiple redundancy structure to improve the hardware fault margin of the system. A single fault will not lead to the loss of SIS safety functions. (4) The application program is easy to modify and can be modified according to actual needs for software. (5) The self-diagnosis coverage is large, and the number of points that workers need to check when maintaining is relatively small. (6) The response speed is fast. The response time from input change to output change is generally around 10-50ms. The response time of some small SIS is even shorter. (7) It can achieve the safety design of the entire loop from sensors to actuators, and has monitoring functions such as I/O short circuit and break.