Situation Awareness - ISA 101 High Performance HMI

Situation awareness is the perception of environmental elements with respect to time or space, the comprehension of their meaning, and the projection of their status after some variable has changed. It is a field of study concerned with perception of the environment - critical to decision-makers in complex, dynamic areas ranging from aviation, air traffic control, ship navigation, industrial plant operations, military command and control, etc. Having complete, accurate and up-to-the-minute situation awareness is essential where technological and situational complexity on the human decision-maker are a concern.

Instrument Society of America (ISA) 101 Standard
The ISA 101 Standard embraces situation awareness by addressing the design, implementation, and maintenance of human machine interfaces (HMIs) for process automation systems. In so doing, it effectively…

Adroit High Performance ISA 101 HMI
The upcoming 8.4 release includes Adroit’s implementation of ISA 101 in the form of a toolkit that contains controls, wizards, and examples of the necessary graphic symbols and elements to build an HMI application. In meeting the ISA 101 requirements, three primary principles have emerged:




ISA 101 conventions and stipulations

Depicting Alarms
Alarms are divided into 5 priorities, each with an associated colour and geometric shapes: Priority 0 (Blue) is reserved for diagnostic events. Alarms for process variables that have been suppressed (alarm inhibited) are shown with a unique suppressed symbol using a white background:

With regard to audible alarm annunciation, where used, each one of the different alarm priorities should have its own unique alarm sound. For example – Priority 4 Highest – railway crossing bell. The sounds chosen must not be used by any other process or interface in the control room.

An example of this can be seen in theObject Modelling Quick Start Guide, where we create various alarm indications for a hypothetical Pressure Relief Valve.

Contents of the Adroit ISA 101 toolkit
The toolkit essentially consists of a number of graphic form controls and wizards that implement the various elements and artefacts recommended by the ISA 101 standard.

The information content of trends is far more valuable than the mere display of many P&ID elements on a graphic page. Trends are implemented with the following capabilities and characteristics:

Spark Line
When precision is not essential, and simple direction, magnitude, and amount of change is sufficient, a small unlabelled trend is placed next to a process value. The shaded area of a spark line trend represents the normal operating range. Clicking on the spark line brings up the normal range and time, e.g. +- 2° C / 1h

Process Vessel Trend
There are several methods to display the analog value of a vessel. The goal is to depict the level without undue emphasis or distraction. A trend line is used to display the value:
  • Vessel is shown as 2-dimensional
  • Outline is thin (1-pixel) black line
  • Trend timespan is configurable
  • 3 different sizes are available (small, medium, large)
  • With either 2 or 4 alarm set points
  • Vertical orientation only

Analog Indicator
The purpose is to represent the operating state of an analog value graphically so as to be assimilated at a glance:
  • 3 different sizes (small, medium, large)
  • 2 different orientations (vertical, horizontal)
  • Normal operating range is pale blue
  • Inner alarm limits are light grey
  • Outer alarm limits are dark grey
  • Current value shown as dark blue index
  • Trending direction show as directional grey arrow

A controller is thought of and depicted as a physical entity. This way, proper information about its operational status can clearly be shown:
  • Process value – expressed in engineering units
  • Set point value – expressed in engineering units
  • Output value – expressed as a percentage
  • Mode – digital value showing Auto or Manual

Radar Plot
A radar plot is used to create a PRO (Pattern Recognition Object) display element. It produces a polygon shape by plotting each process variable’s current value on a separate plane. It is based on the premise that the retention and recognition power of the human brain is far greater for shapes than it is for a set on numbers:
  • Minimum of 3 and a maximum of 17 process variables
  • Captures and saves process variable values for future reference
  • Recalls pre-captured patterns and superimposes them under real-time pattern
  • Indicates alarms. When any of the process variables goes into alarm, the shape changes colour based on the highest priority in force. The reading(s) in alarm are highlighted
  • The name of each variable and its value can be seen as a tool-tip when the mouse hovers over the relevant axis

Production Target Trend
This trend is used to give operators an indication of how they are performing against a set target. It is also dynamic in that it can be reset with new target value after a process change so that operators are then able to see performance relative to the new target.

Standard ISA Shapes
Different sizes of various standard ISA shapes are provided, once again making use of pattern recognition so that objects can be recognized at a glance. Labelling is not intrusive or of high visibility. In fact, not every item needs a label identification. In particular, tag names are not routinely displayed as they only add unnecessary visual clutter.