IEEE Std 1865.2-2019 pdf download – IEEE Standard Specifications for Maintenance and Test of Distributed Control Systems in Thermal Power Stations: Operation Service and Management.
5.2.3.2 Inspection of data acquisition signals Based on the requirements for design of process systems of a power plant, the designed I/O signals are continuously acquired and processed, and then stored in real-time and historical databases, so as to achieve the information sharing of the DCS. The reliability and accuracy of data acquisition helps ensure the safe operation of control and protection system; therefore, inspection shall be performed to identify and record abnormal indications in time: a) Check the screen displays of the DCS to verify that all signals are used in response to the operational requirements of the unit. Record the signals that could not be used in the operation and verify that the record for the cause analysis and the solution plan are in place. b) Check the display values of the parameters to verify that they are consistent with the actual situation of the power production process without signifcant deviations. Check the actual value and the historical trend of the parameters to verify that the requirements for the process control are satisfed and the display is normal. Record and print the displays and curves of the abnormal parameters, such as wrong parameter values, curve upside-down, sudden change, fuctuation, discontinuousness, signal rate protection action, over range, etc. c) The operation mode of the redundancy signal shall follow the requirements for the reliability of operation monitoring. d) The deviation of the same measured parameter transmitted from different sensors shall be less than the permissible comprehensive error of the measurement system. The deviation of redundancy signals with the same measurement accuracy shall not be greater than twice the allowable comprehensive error of the measuring system. e) During normal operation, frequent alarm signals and fickering of too many parameters shall not occur on display.