BS/EN 61069-6-2016 pdf download.Industrial-process measurement, control and automation Evaluation of system properties for the purpose of system assessment Part 6: Assessment of system operability.
Some aspects can be quantified by analysing the ergonomic aspects of the properties, and by measuring the number of actions and time required to accomplish a given task (the efficiency of the human-machine interface), others can be qualified in a descriptive way.
Efficiency, intuitiveness, transparency and robustness each cannot be quantified as a single number, However they can be expressed by a qualitative description containing some quantified elements, such as:
— a coverage factor, obtained by comparing the operating means provided by the system with the specific requirements as stated in the system requirements document;
— applicable ergonomic standards; and
— the time required to give a command, and to request information.
4.1.2 Efficiency
A system has operability efficiency it it allows the operator, with a minimum risk of making errors, to perform his task(s) with a minimum amount of mental and physical effort within an acceptable time frame.
The extent to which the operating means provided by the system minimise operator time and effort required In using the system to accomplish his tasks within stated constraints is a measure of the operability efficiency of the system.
The operability efficiency depends, among others, on the following elements:
— the ergonomic design of the devices (keyboard, mouse, voice input, dedicated knobs, screens, indicators. etc.) used as operating means in support of the human-machine interface;
— the geographical lay-out, the number of these devices and their relative location on the operators’ workplace;
— the shape of the operators’ workplace;
— the limitations imposed by the operating environment and protective clothing (indoor, outdoor, day, night, goggles, gloves, etc.);
— the methods to be used to retrieve information, to issue commands, etc.
4.1.3 Intuitiveness
Intuitiveness represents the simplicity and instant understanding the system provides, which enables the operators to give commands and present information to the operators. Additionally intuitiveness takes into account the skills, educational level and general culture of the operators, who are performing tasks, by using the functions provided by the system.
This domain can be defined in terms of culture, international and/or proprietary standards, etc.
4.1.4 Transparency
Transparency represents the ability, of the operating means provided by the system, to seemingly place the operator in direct contact with his tasks. This enables the operator to give commands and view information, returned from the system, with a realistic view of the actions (and their sequence).
The extent to which these means are provided is a measure of the transparency of the system. The transparency depends on the following factors:
— the logical principles followed to present the functional and geographical structure of the process and the tasks to be performed by the operator;
— the way in which labels and names are used to identify the operating means, and the consistency of their use;
— the consistency in the application of colours, names, audible signals, etc. throughout all tasks and levels of Information;
— the way of the dynamics of the tasks are realistically simulated, to give the operator a ‘real” feel of the task to be performed, etc.
Transparency includes that the information presented by the system is clear, concise, unambiguous, and non-contradictory. Non self-explanatory information can be explained by a more detailed description in easily accessible documentation or a help function for transparency.
4.1.5 Robustness
Robustness includes that the operating means provided by the system to enable the operator to give commands correctly interpret and respond to any operator action. If the operation means are ambiguous. additional information can be requested by the system for removing the ambiguities.
Robustness depends on the following factors:
— the extent to which deviation from the standard generic rules is permitted, and is interpreted;
— the extent to which the system is able to detect and notify deviations and to couple these deviations with requests for further information, etc.BS/EN 61069-6-2016 pdf download.