9
How HMI Has Been Evolving
When addressing these concerns, a systematic analysis must be performed based on
a task analysis of the work that the operator is doing within the actual timeframe. A
time plot of the tasks, workload analysis, and Management of Organizational Change
Study are required to identify whether the operator can safely bring all those units to
a safe state in a timely manner.
The analysis must also consider the number of deviations that can happen, i.e., the
need for a close look at the number of alarms generated by each of the process units,
which may exceed the operator’s ability.
Finally, we must go back to the number of screens an operator can effectively manage. The standards suggest four screens. However, that does not allow for a second
or third operator at the console during s tart-up and disturbances. A full Ergonomic
Assessment is necessary for the control room and the desk to eliminate things that
could compromise situation awareness.
CONTROL ROOMS AND SA HAVE NOT NECESSARILY
EVOLVED WITH THE NEW HMI
A few things that can compromise situation awareness ( SA) have already been mentioned. Still, a more i n-depth look would require the review of the control room itself,
the operator’s console design, the number of screens, distance of the screen from the
operator, and viewing angles. ( In addition to a description of work processes, collaboration and interaction with actors outside the control room).
The screen layouts and navigation techniques must conform with the Philosophy
and Style Guide, which will have rules for colour usage, text size, font types, line
usage, arrow usage, navigation, hierarchy, and consistent use of objects and their
placement on screens.
Once we have control of the number of screens that are optimal for the control
operator, we can consider the console furniture and if features such as sit/ stand will
be available as recommended by most ergonomic studies. The trend today is to provide a large overview screen either above the console or on an adjacent wall. An
overview of the operator’s scope of control is on this display. It should have all the
critical information which the operator must respond to immediately, whether it is
safety, environmental, or process related. How the data should be displayed is found
in the ISA 101 standard ( human–machine interfaces).
Level 1 screens give an overview, where the structure can go down to level 4 details.
The console desktop screens display Level 2, 3, and 4 displays. Under “ Normal” circumstances just Level 2 displays would populate the desktop screens. Level 2 displays
monitor and control approximately 80% of a section of the Level 1 displays.
Level 3 displays are typically the traditional P&ID view of the process with more
detail than the Level 2 screens. Level 4 screens are used for fine details and diagnostics and testing information. It is still allowed to have a screen of faceplate displays
similar to the original eight used in the early days, as this allows the operators to
make multiple quick changes grouped by task. Hence, the hierarchy reveals more and
more specifics as the operator navigates from Level 2 to 4 data ( Figure 1.11).
One of the differences between traditional displays and h igh-performance displays
is to make the operator proactive rather than the traditional being reactive. At the same
How HMI Has Been Evolving
When addressing these concerns, a systematic analysis must be performed based on
a task analysis of the work that the operator is doing within the actual timeframe. A
time plot of the tasks, workload analysis, and Management of Organizational Change
Study are required to identify whether the operator can safely bring all those units to
a safe state in a timely manner.
The analysis must also consider the number of deviations that can happen, i.e., the
need for a close look at the number of alarms generated by each of the process units,
which may exceed the operator’s ability.
Finally, we must go back to the number of screens an operator can effectively manage. The standards suggest four screens. However, that does not allow for a second
or third operator at the console during s tart-up and disturbances. A full Ergonomic
Assessment is necessary for the control room and the desk to eliminate things that
could compromise situation awareness.
CONTROL ROOMS AND SA HAVE NOT NECESSARILY
EVOLVED WITH THE NEW HMI
A few things that can compromise situation awareness ( SA) have already been mentioned. Still, a more i n-depth look would require the review of the control room itself,
the operator’s console design, the number of screens, distance of the screen from the
operator, and viewing angles. ( In addition to a description of work processes, collaboration and interaction with actors outside the control room).
The screen layouts and navigation techniques must conform with the Philosophy
and Style Guide, which will have rules for colour usage, text size, font types, line
usage, arrow usage, navigation, hierarchy, and consistent use of objects and their
placement on screens.
Once we have control of the number of screens that are optimal for the control
operator, we can consider the console furniture and if features such as sit/ stand will
be available as recommended by most ergonomic studies. The trend today is to provide a large overview screen either above the console or on an adjacent wall. An
overview of the operator’s scope of control is on this display. It should have all the
critical information which the operator must respond to immediately, whether it is
safety, environmental, or process related. How the data should be displayed is found
in the ISA 101 standard ( human–machine interfaces).
Level 1 screens give an overview, where the structure can go down to level 4 details.
The console desktop screens display Level 2, 3, and 4 displays. Under “ Normal” circumstances just Level 2 displays would populate the desktop screens. Level 2 displays
monitor and control approximately 80% of a section of the Level 1 displays.
Level 3 displays are typically the traditional P&ID view of the process with more
detail than the Level 2 screens. Level 4 screens are used for fine details and diagnostics and testing information. It is still allowed to have a screen of faceplate displays
similar to the original eight used in the early days, as this allows the operators to
make multiple quick changes grouped by task. Hence, the hierarchy reveals more and
more specifics as the operator navigates from Level 2 to 4 data ( Figure 1.11).
One of the differences between traditional displays and h igh-performance displays
is to make the operator proactive rather than the traditional being reactive. At the same