Ergonomic principles for the design of control centres Part 9 : Displays， controls， interactions
Some standard content:
DL/T 575. 9-1999
This standard is compiled with reference to the contents of displays, controllers and interactions in the research results of ergonomics standardization at home and abroad (see Appendix A).
This series of standards DL/T575 is titled "Guidelines for ergonomics design of control centers" and includes the following 12 sub-standards: DL/T575.1 Guidelines for ergonomics design of control centers Part 1: Terms and definitions; DL/T575.2 Guidelines for ergonomics design of control centers DL/T575.3 Guidelines for ergonomics design of control centers DL/T575.4 Guidelines for ergonomics design of control centers DL/T575.5 Guidelines for ergonomics design of control centers 6 Guidelines for ergonomics design of control centers
DL/T 575. 6
Guidelines for ergonomics design of control centers
DL/T 575.7#
Part 2: Field of view and division of viewing area;
Part 3: Division of hand reach and operating area; Part 4: Dimensions of confined space;
Part 5: Design principles of control center;
Part 6: Principles of overall layout of control center; Part 7: Layout of control room;
Guidelines for ergonomic design of control center
Part 8: Layout and dimensions of workstations; DL/T 575.8
DI/T575.9Guidelines for ergonomic design of control center Part 9: Displays, controllers and interactions; DL/T575.10Guidelines for ergonomic design of control center DL/T575.11Guidelines for ergonomic design of control center Part 10: Principles of environmental requirements;
Part 11: Evaluation principles of control room; 』Part 12: Visual display terminal (VDT) workstation. Guidelines for the design of ergonomics for control centres
DI/T 575. 12
Appendix A of this standard is a suggestive appendix.
This series of standards was proposed by the former Ministry of Electric Power Industry of the People's Republic of China. The drafting units of this standard are: China Institute of Standardization and Information Classification and Coding, Electric Power Automation Research Institute of State Power Corporation, and Suzhou Thermal Engineering Research Institute of State Power Corporation.
Main drafters of this standard are: Liu Wei, Tong Shizhong, Wu Dangshi, Hua Donghong, and Sheng Jufang. 1319
1 Scope
Electric Power Industry Standard of the People's Republic of China
Guidelines for the design of ergonomics for control centres
Part 9: Displays, controls, interactionsDL/T575.9 --1999
This standard specifies the design principles for the input and display of data when the control centre monitors and controls the operation of the system, and gives the requirements and suggestions for the configuration of displays and controllers. This standard applies to the design of all types of newly built control centers, as well as to the technical transformation design of existing control centers. 2 Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. DL/T575.1-1999 Guidelines for ergonomic design of control centers Part 1: Terms and definitions DL/F575.5-1999 Guidelines for ergonomic design of control centers Part 5: Design principles of control centers DL/T575.6-1999 Guidelines for ergonomic design of control centers Part 6: Principles of overall layout of control centers DL/T575.7-1999 Guidelines for ergonomic design of control centers Part 7: Layout of control room DI./T575.8-1999 Guidelines for ergonomic design of control centers Part 1 Part 8: Layout and dimensions of workstations Dl./T575.12-1999 Guidelines for ergonomic design of control centers Part 12: Visual display terminal (VDT) workstations 3 Definitions
The definitions adopted in this standard are given in Dl./T575.1--1999. 4 Displays, controllers and interactions
4.1 Guiding principles
Displays and controllers constitute the human-machine interface, the goal of which is to make human-machine interaction easy (less effort), fast (less time) and with minimal errors. The basic idea of guiding design is: a) In the human-machine system, people should always be in the dominant position, because the operation of the system is determined and executed by the operator. Only when the safety of personnel or equipment is endangered and a clear response is required to be made quickly and reliably, the protection system will complete this response (such as terminating the operation process to avoid danger or loss).
b) When designing the human-machine interface, people's abilities, characteristics, skills, tasks and physiological and psychological needs should be considered. c) The human-machine interface should provide a variety of information and means to enable the operator to complete his control task. 4.2 Expression principles
4.2.1 Distinguish the difference between information (or data) and its expression form. Determine the display content first, then consider the expression form. Approved by the State Economic and Trade Commission of the People's Republic of China on February 24, 2000 1320
2000-07-01 implementation
DL/T 575. 9 ---1999
4.2.2 The operator must be aware of the events that require his response. a) In order to avoid overloading the operator, the displayed events should be classified according to their priority to help the operator make decisions. b) The more urgent the event is, the higher its priority should be, and the more obvious its display method should be. 4.2.3 The displayed information should ensure authenticity
Incorrect information will lead to wrong decisions, which may cause failures or even accidents. True information means that the time, location, value, status, event process and previous and subsequent connections provided by the information are correct. The display of information has the following requirements:
a) Timely update and display of real-time information.
b) For all key information, sufficient redundant information should be displayed so that the operator can verify the displayed information.
b) Displays that do not meet the above requirements should be explained. For example, if the signal showing the valve "closed" is not generated from the position of the valve, but from the switch that causes the valve to close; the information transmission of a measuring point is interrupted, so there is no update of information. If such a situation is not explained, the information displayed at this time is not true. 4.2.4 Expressions should be clear and consistent
4.2.4.1 Clarity
a) When explaining the expression content, use known codes or codes that the operator is familiar with. b) Avoid exceptional codes.
4.2.4.2 Consistency
a) The same code should be used regardless of where the code is displayed at the same work location. b) The same type of information should be represented in the same way, that is, the same terminology, name, color and topology (layout) should be used for the same equipment, event, status, etc.
c) The difference in the representation of different information should be obvious. d) For the same objects at different levels, the displayed images should be as similar as possible. This can be solved by keeping the basic display image (such as symbols) of the high-level objects and adding details to the images of the lower-level objects when necessary. 4.3 Principles of control and system response
4.3.1 The relationship between control actions and system responses a) Every input of the operator should cause the system to respond. b) A specific control action should only cause the corresponding response of the system. Otherwise (such as due to a fault), the operator should be informed of the abnormality.
c) The response caused by the control action should be what the operator expects. d) Pay attention to the coordination between the display and the control action e) The system response should appear within the specified time. If the system fails to achieve the response caused by the control action within this time, there should be a prompt to inform the operator that the system is busy processing this task at this time. 4.3.2 Appropriate selection of display objects
a) Only the objects to be controlled should be displayed on the screen. b) The direct reaction caused by the control action should be displayed on the screen, and the further indirect reaction caused by the controlled object should be perceived. From the above principles, it can be concluded that the design of the human-machine interface depends on the tasks to be completed using the display and controller, as well as the characteristics of the operation, environment and available technology. Therefore, if the task is not understood, this standard cannot be applied. 5 Design process
The following requirements should be considered when designing the human-machine interface: a) According to 1DL/T575.5. The design of the human-machine interface must first be task analyzed, including determining the activities that people need to complete and the activities that operators need to perform at each work location. b) The personnel composition of the design team is very important. It should include ergonomics experts, control engineers, computer experts, and future users (operation management personnel, especially operators) and other personnel from multiple disciplines. In order to ensure the success of the design, future users should be absorbed into the design team; contact should be maintained with potential users to solicit their opinions. The design of the human-machine interface can be carried out in the following steps. In actual work, there is often an iterative process between the steps. 5.1 Step 1: Determine the control room operators and their tasks at their jobs. 5.1.1 These jobs can be used to complete the following two types of tasks: a) Specialize in completing a specific task (such as process control) b) Alternately complete multiple tasks (such as control engineering, process control, maintenance). In this case, the design of the job should focus on the main task and put temporary use requirements in a secondary position. Note: For each item that is performed alternately, the requirements in step 2 should be completed. 5.1.2 In any of the above cases, the following should be clarified: a) The types of tasks that must be completed at each work station, b) The number of personnel required for each task in normal operating mode. c) The number of personnel who should be in a work station to jointly handle the problem in the event of a failure. 5.2 Step 2: List the activities assigned to people at each work station 5.2.1 Each task to be completed at each work station should be specified, as follows: a) Required visual display information.
b) Visual information that should be displayed on the screen (other information can be obtained by observing the process through the window). c) Information that needs to be displayed on the screen at the same time. d) Practical control actions.
e) Information that needs to be expressed in words, and this is used to determine the layout of the work station (see DL/T575.7). 5.2.2 It should be emphasized that:
a) The worst case should be described in detail. b) The exceptions to the above provisions should be listed and the handling methods should be explained, including the number of operators, the number of work positions, equipment conditions, countermeasures, collaborators and the work positions they are in.
5.2.3 Design requirements:
This stage only seeks the information required to complete the task rather than its expression method (such as text, simulation diagrams, curves, etc.) and available technology. The purpose is to focus on the following issues:
a) What must be displayed.
b) What must be controlled (rather than how to control it). Note: The early stages of design are mainly centered around data and information, and its expression method is determined in step 9. 5.3 Step 3: Organize the collected information into images. Generally, it is impossible to display all the variables that the operator wants to evaluate on one display at the same time. Even if multiple parallel display screens are used, they still need to be displayed in sequence on the same screen. Therefore, it is required to organize all the information into several image formats. In the control center, in addition to displays and controllers, some additional equipment may be needed, such as gas alarm screens, fire detection screens, closed-circuit television and camera control devices, communication screens, etc. The locations of these devices and the displays and controllers on them should be listed. Displays and controllers in operation are sometimes used by maintenance personnel or instrument and control engineers to debug the system or change the settings of the automatic system.
Design requirements are shown in 5.3.1~5.3.5.
5.3.1 Use a hierarchical structure
Using a hierarchical structure is conducive to establishing a thinking mode and making positioning easier. In any case, users should be able to easily find answers to the following questions:
a) What stage is the process in?
b) Where can I go from here?
c) How can I get the required information?
5.3.2 Operator's task as the criterion
DL/T 575.9 --1999
a) For monitoring tasks: always set up an overview of the operating conditions of all the equipment monitored by the operator. b) For control tasks: display the controlled object according to the required level of detail, as well as the various indirect reactions caused by it. c) For diagnostic tasks: provide more detailed information so that the operator can accurately determine the fault and decide on the appropriate method to keep the process running.
5.3.3 Prepare data combinations for abnormal conditions Prepare multiple data (image) combinations for various abnormal conditions, and analyze the operator's response to various alarms: 5.3.4 Obtaining information
In addition to the above preparations (see 5.3.3), it should also be possible to obtain information suitable for different conditions through the following methods: a) Call up images according to selection criteria, for example, the operator may have such a need: "Display the alarms generated by facilities named with the letter AB".
b) Use hypermedia links, for example, the operator can call up the process or alarm that exceeded the limit value in the past hour according to the current value of the variable displayed on the simulation screen.
Note: The content of the images used in 5.3.3 and 5.3.4 shall be determined according to the requirements of step 8. 5.3.5 Name of the image
Each image should be accurately identified. Therefore, the name of each image should be unique. When determining the name, the following should be considered: a) The name of the image should be located at the top of the image as a title. b) It can indicate what the image represents (such as a specific unit). c) It simplifies the positioning process, bzxz.net
Note: It should be ensured that the selected name can distinguish between images that look the same even if they are the same. 5.4 Step 4: Determine the number of screen displays and traditional displays The number of displays (including screen displays and traditional displays) must ensure that the operator can provide enough information at the same time to handle the worst working conditions that can be foreseen in the design. Note: In practice or text, screen displays are often referred to as displays. Specific design requirements are shown in 5.4.1 to 5.4.3.
5.4.1 Traditional displays and controllers can be used as backup equipment to provide operators with critical information and maintain control of the system when the computer is shut down or in an emergency. 5.4.2 The number of screen displays is determined by the following factors: a) The amount of information required at the same time:
1) The worst working condition should be considered. In this case, the operator must obtain as much relevant information as possible and complete a series of control operations in the shortest possible time; 2) The operator's short-term memory problem should be considered. If the information currently required must be obtained from several displays, the operator will definitely be under great pressure;
3) In the event of a screen display failure, the remaining displays (including dedicated displays and monitors) should be able to provide all the information required for the operator to continue working. b) Combine the required expressions in parallel (for example, combine multiple displays using full-screen format to display a permanent overview, an alarm list, and a curve that changes over time). 5.4.3 Make use of the experience gained from existing jobs with similar functions as much as possible. 5.5 Step 5: Select displays and monitors for each work position 5.5.1 Basic requirements
Usually, large-screen displays or desktop displays can be selected. In addition, the following conditions must be considered: a) When selecting the size of displays and large-screen displays, a fixed viewing angle should be considered rather than the viewing distance (i.e., the font height should be doubled when the viewing distance is doubled). DL/T575.9—1999
b) The required viewing angle depends on the work task, color and viewing conditions, c) Take measures such as allowing redundant configuration and changing the allocation of displays, so that in the event of failure of one or more displays, even large-screen displays, the operator can still monitor and control the system and enable the system to operate safely. 5.5.2 Desktop monitors
For requirements on desktop monitors, see DL/T575.8 and DL/T575.12.5.5.3 Large-screen monitors
5.5.3.1 Application of large-screen monitors
a) In most cases, large-screen monitors are used as shared monitors outside workstations to provide the same information to multiple people at the same time. b) Before deciding to use a large-screen monitor, it is necessary to consider that the area required to display an image increases with the viewing distance (that is, if the viewing distance doubles, the display area needs to be increased fourfold). The maximum viewing distance can be determined as follows: 1) The user begins to be unable to see the image structure (such as lines) displayed on the screen; 2) If the observer must observe from a certain position, the observer's eyes must be within the "recognition space" (see DI./T575.81999, 5.2).
5.5.3.2 Requirements for large-screen display design a) Consideration should be given to the fact that a larger screen does not necessarily convey more information or images (because it is viewed from a greater distance). The size of the image is mainly determined by the viewing angle. If the viewing distance is doubled, the character height must also be doubled if the viewing angle remains unchanged. b) Providing each operator with a personal dedicated display (rather than a large shared screen) often has advantages in terms of independence, adaptability to input devices (such as keyboards) and displays, economy, and total display availability. c) In practical applications, the combination of a large overview display and a personal display usually meets the requirements well. d) If a personal display and a large-screen display are used at the same time at the workstation, the user's line of sight should not frequently move from one screen to another in terms of information distribution. e) Before changing the image on the large screen, the consent of all users should be obtained. Sometimes, some operators may still need the current image while others have already begun to need the next image. For this purpose, the method in f) can be used. f) Divide the large screen into several areas, each of which is specifically assigned to a person at the workstation. An operator can only change the display content of the area assigned to him. g) Off-screen pointing devices (such as mice and trackballs) should be used so that the operator can keep his eyes on the screen while executing the control program. Devices such as keyboards should not be used, which force the operator to frequently shift his eyes between the display and the control device during operation.
h) When setting up a large-screen display, redundant displays (such as redundant personal displays) should also be provided to keep the current information displayed.
i) Due to the poor flexibility of traditional screens, it is recommended not to use traditional screens with specific displays and controls in work locations where performance indicators change frequently.
j) For some display technologies whose contrast is strongly dependent on the viewing angle, the recognition space (see DL/T575.8) may be limited. The degree of limitation depends on the viewing angle at which the contrast reaches the minimum required value (such as 3:1). k) The maximum viewing distance is determined by the size of the characters and the viewing angle. If a certain viewing distance is required, the character size should be selected appropriately according to the requirements.
5.6 Step 6: The layout design requirements for the screen display and traditional display at each work station are as follows:
a) When arranging traditional displays and controllers, the requirements of Part 4 in Appendix A [6] may be followed. b) When arranging the screen display at each work station, the requirements in DLT575.8 shall be followed. 5.7 Step 7: Distribution of various types of display information on the screen Generally speaking, each screen can be equipped with any type of information (such as overview diagrams, curves, simulation diagrams, alarm lists, tables, etc.). This will facilitate the replacement of a failed display with another display to provide important information (such as overview diagrams). The design requirements are shown in 5.7.1~5.7.4.
5.7.1 Positioning by information category allows the same type of information (such as overview diagrams) to be observed at a fixed location. 5.7.2 Each work station should have an overview diagram that always displays the latest information. The overview map should provide all the working conditions that the operator's workstation is responsible for. In addition, the overview map should also serve as the starting point for searching in the images of each level. 5.7.3 The overview map can be displayed in the following ways: a) Vertical screen (usually this screen can be used from more than one workstation). b) Specific overview map display screen (a dedicated display can be set up at each workstation or a large screen display can be used instead of the vertical screen).
c) Each screen is divided into several areas, one of which is dedicated to displaying the overview map (when the number of parameters required for the overview map is small, this method is recommended). Its characteristics are as follows. 1) Advantages:
No need to prepare an additional spare display for displaying the overview map; other images can be called up directly from the overview map on each screen; flexible use of the screen (it can be decided at any time whether the displayed image should be retained or changed). 2) Disadvantages:
Limited area;
-Requires an area on each display screen to display the same information 5.7.4 If a sequence of important events or the trend of changes in certain process variables needs to be displayed frequently, a dedicated screen can be used to display alarm lists and curve charts.
5.8 Step 8: Determine the content of the image
After all the data required by the operator to perform the task are arranged (step 2) and organized (step 3), the content of each image must be determined. The tasks of step 8 must be completed in close coordination with step 9. Design requirements are shown in 5.8.1~5.8.3.
5.8.1 Determine the content that each image should display: a) Information needed immediately: display the interrelated variables required by the process. b) Urgency: assign status information and other information according to priority; determine the priority according to the speed at which the operator should respond. For example: when using two-level alarms, according to Table 1. Table 1 Alarm priority
Priority
Operator response
Require immediate response
Require attention
Yellow Blue Blue
If it is new information, it will flash before confirmation
c) Level of detail: mainly determined by the level to which the image belongs, that is, related to the corresponding task (see step 3). d The amount of content, the number of processes contained in each simulation diagram, the number of lines to be displayed in each display curve, etc. e) The format to be used: simulation diagram, curve, a set of characteristic diagrams, alarm list, etc. f) Accuracy: the number of significant digits required for digital variables; the accuracy measured by the measuring device; the appropriate resolution required for analog display (such as curve, bar chart).
5.8.2 Establish an appropriate relationship between information and data: a) Provide just enough data to meet the needs so that the displayed information can be clearly interpreted. b) Avoid showing details (e.g. pipe connections, 3D schematics of circular equipment) which may exist in reality but have no relation to the task specified in the image. Note: Details not relevant to the task are a distraction to the work and a burden to the image, complicating the extraction of the truly important information. 1325
DL/T 575.9--1999
5.8.3 Avoid using overcrowded images and distinguish between the following two situations: a) Elements that are continuously required (e.g. symbols, pipes, variables, etc.). These elements convey special information and are relevant to the correct understanding of the image. b) Elements that are occasionally required (e.g. label names, scales, etc.). These elements should be displayed temporarily when needed. Note: To adapt to various situations, it may be necessary to display additional information in the image. Windows can be used for this purpose (see step 10 for details). 5.9 Step 9: Determine the code character table
5.9.1 In order to accurately and quickly interpret data and information, the displayed elements (such as names, symbols, colors, etc.) should be uniformly assigned to several information categories (such as operating mode, type of media to be processed). The following methods can be used: a) Assign at least one unique expression element (such as a special shape, a certain symbol or character sequence) to each type of data (mainly the model of the device).
b) Modify the displayed elements or add some information to indicate the current mode. c) Use visual coding methods, such as shape, color, orientation and flashing coding (see Appendix A [7] for details). 5.9.2 Design requirements: Determine the code (assignment) at the beginning of the project and keep it consistent throughout the application. The specific requirements are as follows.
a) Determine what must be displayed: list all types of equipment with their possible unique states (e.g., a certain type of "motor" may have three states: On, Off, and Interference), and display these states at different levels. b) Use standard codes (e.g., the mimic diagram symbols in Appendix A-4) or codes that are already familiar to future users. c) Select the attributes of the code according to the hierarchical model of the degree of awareness. d) Use multidimensional coding, especially combining color codes with at least one other code. 5.10 Step 10: Develop control procedures
This design is based on the results of steps 2 and 3. The control procedures are developed entirely based on the purpose, control statements (i.e., the order in which objects, operations, and quantitative indicators are given) and the dialogue method (command language, mutual question-and-answer dialogue, menu, fill-in-the-blank method). In addition, measures to reduce errors should be developed. 5.10.1 Control Purpose
a) Positioning:
1) How to obtain the various displays of information required to handle the current situation? 2) How to obtain the information format that best suits the user's current work? b) Adjust the display.
c) Acknowledge alarms.
d) Adjust variables.
e) Change the operating mode (state).
5.10.2 Control Statements
a) To complete a control action, it is necessary to specify the control object, the corresponding operation, and the quantitative indicators of the operation. Example: A control action can be expressed as: "Increase the set value of FRC212 by 5%"
Quantitative index
-FRC212 set value"
-"increase"
b) In a computer-based system, if an object is selected, the system can immediately respond and provide corresponding (virtual) keys to control the selected object.
Example:
If "motor" is selected as the object, the two keys "on" and "off" will appear; if "set value" is selected as the object, the two keys "increase" and "decrease" will be provided, etc. 5.10.3 Reducing errors
DL/T 575.9 -1999
To prevent erroneous control actions and avoid adverse consequences, the following measures can be taken: a) For frequently used control actions, if they are easy to cancel after operation and will not cause serious consequences, they can be controlled by single-clicking.
b) For control actions whose operation consequences are not serious (such as only delaying time and wasting energy) and can be eliminated, the control results should be displayed so that the operator can check and correct them in time. c) For irreversible control actions (such as boiler ignition and electrical equipment grid connection), there should be a confirmation process (such as pressing the confirmation key) before execution. , so as to avoid inconsistency. Note: Using the control statements described above can reduce the occurrence of omissions. d) Control actions and data inputs should be checked by the control system in the following two cases: 1) Control actions or input data are ambiguous, 2) Control actions and input data are absolutely or relatively in different ranges with respect to the current value. 5.10.4 General requirements for human-computer dialogue
a) Dialogue should support the operator to complete tasks quickly and effectively. b) Dialogue should only provide information related to the task to be completed by the operator. c) Those that are used for automatic execution and can be appropriately divided The control actions of the distribution interface software should be performed by the software. For example, in the system startup program, the cursor is automatically placed in the first login area related to the task. d) The format of input and output should be appropriate, and the input and output data should have a certain precision (i.e. the number of decimal places). e) Support should be given to cyclic tasks that simply repeat a certain sequence of activities, as well as batch sequence control and startup sequence control.
f) The operator does not have to enter system set values or those values that can be obtained at certain locations in the process control system. g) The system feedbacks to the operator, or the system sends the operator a request Each dialogue in which the author explains (self-narrates) should be immediately understandable to the operator.
h) The dialogue should provide feedback after each operation of the operator. If the operator's operation may cause serious consequences, the system should provide an explanation and request confirmation. The way and level of detail of feedback should be determined based on the knowledge level that an average operator should have. Feedback and explanations should minimize the need to consult manuals and other external information. i) The operator should have a sense of autonomy (control ability). j) The operator should be able to initiate and control the direction and speed of each interaction until the goal is achieved. k) When the system remembers, the operator should be shown the next operation instruction (give the time to wait). 1) The dialogue should be fault-tolerant and a prompt should be given when an input is obviously wrong. m) The dialogue should be consistent:
1) The position where the system responds should be predictable; 2) Standard positions should be used to display prompts of the same type, such as alarms, image recognition, command input areas, etc. The symbols used should be located adjacent to the displayed graphic outline or device symbol (above or to the left). n) The dialogue should be reversible:
1) Images or pages should be scrollable;
2) Each input should be undoable.
0) When a dialogue can support and guide the user to learn to use the system, then this dialogue is suitable for learning. P) Rules and basic concepts that are conducive to learning should be provided; various applications of process control and tools used by operators to manage the input and output of application processes should be explained; simulation tools can enable operators to try "what if" without immediately affecting the process.
9) Operators should be provided with shortcut keys and system settings for frequently used commands. r) Commands that are not frequently used should be designed to be more self-explanatory and accompanied by guidance information. s) Reduce the number of rules that need to be learned. 1327
5.11 Step 11: Application of windows Rules
5.11.1 Application of windows
DL/T 575.9 --1999
When using windows, two facts must be carefully and explicitly considered: process control or command and control are real-time tasks; the occurrence of a large number of events forces operators to react in a timely manner and they must be notified immediately. Note: Windows on the screen always hinder the observation of the image on the screen. 5.11.2 Design requirements
a) There must be no windows in the overview display. b) Windows should only appear when the operator needs them. Exception: In the event of a system failure, neither updating nor continuing control activities, the system can start a window to provide more important information than from the process.
c) Generally, windows should only appear on the screen temporarily: to provide additional information or virtual control elements for the control object and the current situation (event).
d) Users should be able to close these windows at any time. c) Do not use transparent windows (to avoid blurring). f) Objects and their associated windows (such as with control elements) should appear parallel in the field of view. Note 1: This is to ensure that the system's response to control actions can be observed. Note 2: The window can appear in a fixed position (such as the upper left corner of the screen or in a position related to the object. A better choice is to select a fixed area on the partitioned screen as the window's appearance position. g) Do not display more than two windows on the screen at the same time. Note: The number of windows that appear at the same time will depend on the size of the window, the task, and the density of control elements in the obstructed image. 5.12 Step 12: Select appropriate input devices 5.12.1 Selection principles
The system should give appropriate feedback to the operator's input to inform the operator to confirm and, if necessary, correct his mistakes, including the feeling of pressing a button, the reaction time of a keystroke, the movement rate of the selector (or cursor), feedback information, auditory signals, etc. There are two types of input operations: data entry and point selection. . The general requirements for selecting an input device or combination of input devices are as follows: a) The input device should be appropriate to the operator's task, which is related to the frequency and duration of data entry or selection. For example, it is not necessary to use a large keyboard for tasks where many keys are not in use or text/data entry is infrequent. b) The hardware device of the input device can be dedicated to a specific operation (such as traditional buttons, knob controllers or toggle switches) or general purpose (such as keyboards). In addition, clickers (such as mice) and virtual control elements (such as optical buttons and sliders) can be combined.
5.12.2 Design requirements
5.12.2.1 Traditional controllers
For controllers that require the highest reliability and effectiveness (such as emergency stop devices, fire alarm devices), traditional dedicated control elements should be used. For information on how to select controllers, see Part 3 of Appendix A [6]. 5.12.2.2 Data input device
a) Keyboard:
1) If the operator's task requires data input (letters, numeric characters), a general keyboard should be used; if data input is not required, a special keyboard suitable for completing the task should be preferred. 2) The number of keyboards at work stations should be such that each person working there is equipped with a parallel independent keyboard in the worst case; but appropriate measures should be taken. When one person is performing normal operation, other keyboards will not hinder his work. 3) One or more screens share a keyboard. The main advantage of this is that it can save work space (other equipment may need this space urgently).
DL/T 575.9--1999
Note: The operator must always know which screen he is operating. 4) Membrane keyboards (touch-sensitive) should only be used in dirty or dusty workplaces. Such keyboards are not used in general control centers.
b) Mathematical keyboards:
1) When only absolute values are entered, a numeric keyboard (real or virtual) is used. 2) If a touch-tone telephone is used in the workplace, the layout of the keys on the numeric keyboard should adopt the pattern on the telephone (i.e., the numbers 1, 2, and 3 are in the upper row).
Note: Compared with the numeric layout on a computer, the numeric layout on a telephone has its advantages in terms of ergonomics (fewer errors and time saving). 3) In order to adjust the value (such as fine-tuning the current value), a sliding contact or button (gradual increase or decrease) can also be used. 5.12.2.3 Clickers and virtual control elements Generally speaking, clickers are divided into "on-screen" clickers and "off-screen" clickers. 5.12.2.3.1 Clickers can be used in the following situations. a) The steps used to reach a specific target are limited. b) All selections can be made from one screen. C) Before the operator is allowed to operate (type). d) To reduce typing errors that may have serious consequences. e) When the cursor is used to indicate the position of the control object on the screen, at this time: 1) The cursor position should have obvious visual characteristics (such as shape, brightness and color); 2) Only use the cursor when it is not used frequently. Use a clicker to indicate its position by flashing) The use of a clicker allows the operator to keep an eye on the screen. Note: Clickers are not suitable for text input. 5.12.2.3.2 An off-screen clicker should have the following characteristics. a) It is cursor-based.
b) It can click more accurately than an on-screen clicker. C) It is rugged, easily replaceable, and has a flexible cable connection. d) - A shared clicker should be installed for all primary displays controlled by one operator. 5.12.2.3.3 A mouse should be selected if the following conditions are met. a) There is enough space on the control desk.
b) The same mouse is used c) The same person also uses computer programs for office tasks (such as text editing, spreadsheets, etc.). d) The air and environment are quite clean.
Note: In places where dust, liquids, etc. pose a threat to mechanical clickers, it is preferred to use on-screen clickers such as touch screens or light pens. 5.12.2.3.4 When using on-screen clickers, the following issues should be considered: a) When the shortest operator adopts a forward-leaning sitting posture, the screen should be within the reach of his hand. b) When the operator's elbow is kept stationary at a certain position on the desktop, the operator The user's hand should be able to reach most of the monitor screen.
c) In situations where frequent clicking is required, on-screen clickers should not be used. d) When using a touch screen, parallax adjustment of the cursor to the finger should be used to avoid parallax effects and obstruction of observation of the controlled object.
5.13 Step 13: Physical models and usability checks 5.13.1 Use of physical models
Using physical models can bring many benefits. If it is not possible to use a physical model for every function, at least use a physical model for key expression patterns and interactions. 1329
DL/T 575.9--1999
a) Check the design with future users (for the method used, see Section 11 of Appendix A [5]. b) If a usability check is not possible, at least a pre-test should be conducted. c) Future users should have the opportunity to become familiar with the new human-computer interaction interface, and this should be done by: 1) familiarizing them from the beginning; 2) encouraging their experience and wishes; 3) if possible, trial operation of the system, or at least some parts of the system at an early stage (e.g., several months before delivery).
5.13.2 Revision of the Design Plan
Before implementation of the design plan, the design plan should be revised by the following measures. a) List all problems found during the usability check. b) Prioritize the usability, effectiveness and efficiency issues. The priority ranking can be as follows: 1) Absolutely wrong (meaning "must be eliminated"); 2) Unsuitable (better solutions can be provided that can be processed faster, have lower failure rates and are more economical to implement); 3) Very good.
c) Determine the priority level to which the above problems should be improved. d) Redesign according to the appropriate design steps. 5.14 Step 14: Select the system and check the design solution Check whether the configured display and control system handles all display formats and interaction problems in terms of quality and quantity.2 Modification of the design plan
Before the design plan is implemented, the design plan should be modified by the following measures. a) List all the problems found during the usability check. b) Prioritize the usability, effectiveness and efficiency issues. The priority ranking can be as follows: 1) Absolutely wrong (meaning "must be eliminated"); 2) Unsuitable (can provide better solutions that can be processed faster, have lower failure rates and more economical implementation); 3) Very good.
c) Determine the priority level to which the above problems should be improved. d) Redesign according to the appropriate design steps. 5.14 Step 14: Select the system and check the design plan Check whether the configured display and control system has handled all display formats and interaction issues in terms of quality and quantity.2 Modification of the design plan
Before the design plan is implemented, the design plan should be modified by the following measures. a) List all the problems found during the usability check. b) Prioritize the usability, effectiveness and efficiency issues. The priority ranking can be as follows: 1) Absolutely wrong (meaning "must be eliminated"); 2) Unsuitable (can provide better solutions that can be processed faster, have lower failure rates and more economical implementation); 3) Very good.
c) Determine the priority level to which the above problems should be improved. d) Redesign according to the appropriate design steps. 5.14 Step 14: Select the system and check the design plan Check whether the configured display and control system has handled all display formats and interaction issues in terms of quality and quantity.
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