A human-machine interface (HMI) displays process data from a control system to a human operator. The operator can then monitor the industrial process and transmit control signals using the HMI, which typically takes the form of monitors or touchscreens. An HMI provides graphical representation of the process, alarms and events, historical data logging, reporting, and real-time monitoring capabilities to help operators oversee and supervise control processes.

2.  A human-machine interface (HMI) is a system
that can be connected to the DCS or SCADA
control system and the HMI would display the
process data to the user. The HMI would
display the processed data to a human operator
and by the HMI system, the operator can
monitor and transmit signals to the controllers
to do the required operations.
 HMI as a user control station and mostly this
would be in the form of monitors or touch
screens with buttons attached to it.

3.  Monitoring and controlling of industrial
process
 User-friendly configuration and due to this, it
can also be monitored by a new user
 Good connectivity features it can be connected
to other software, devices, and system
 Powerful thin client technology
 Sophisticated alarm and trending
 True client/server architecture for ease of
scalability

4.  Graphical representation of the process
 Alarms and events – Recording specified changes
and operator actions
 History database, this is to keep the record of the
process values
 Logging -keep logs on the operation of the
automation system
 Reporting – generate incident reports
 It would be useful to monitor and supervise the
control process
 It would represent the plant in real-time
 Statistical process control

5.  HMI would act as the user interface in a process
control system, HMI would provide a graphics-
based visualization of industrial control and
monitoring system. HMI would make sure that the
human-machine interaction can be easily done.
HMI would vary from control panels for power
plants to the screen and input keys of a cell phone.
The major part of an HMI is the interface between
the user and the machine so that users can send
required signals to the controller to control the
machines. The major input device in an HMI
would be the keyboard, toggles, switches,
touchscreens, and mouse. It would display the
progress of the process to the user.

6.  It can detect abnormal situations before the
alarm occurs
 Good success rate in handling abnormal
conditions
 It would quickly complete the abnormal
situation tasks

7.  The HMI graphics is an important way of
representing the industrial process so they
should be descriptive and it should not have
colors with high contrast. In earlier days the
HMI displays were really colorful and it would
poorly depict the numerical data there won’t be
any correlation between the graphics and the
data. It would display less information with
more pictures. Now we can see many changes
in HMI and now there are high-performance
HMI with better graphical features.

9.  Nonschematic depiction
 Limited usage of color
 Grey background is used to reduce the glare
 No animation except for alarm related
 Embedded trends with better parameters
 Analog representation with value relative to normal,
abnormal, and alarm
 Hierarchical display of screens and sub-screens
 Low contrast depiction in 2D not in 3D
 Proper navigation
 Alarm colors would only be used for alarms
 Indicators would only appear in the event of an alarm