7.3.7-3 Numerical Input Values

The HSI should provide feedback to support the user in verifying the correctness of numerical values entered.

Additional Information:
At a minimum, the value should be depicted as digital readout. However, additional feedback can further aid users in detecting input errors. For example, for control setpoints, reference values can convey the implications of the new value for plant operations and, thus, support the user in identifying a value that is too large or too small. Reference values include the actual value of the process variable, the current setpoint value, the normal operating limits, and the alarm limits. Graphical feedback might include a bar chart depicting the input value (i.e., the bar's length corresponds to the magnitude of the entered value). The reference values and the graphical representation may be combined.