Human-Machine Interaction

Human-Machine Interaction entails the study, making a plan and designing the interaction taking place between humans i.e machine users and the machine itself. It basically is a combination of computer science and behavioral science.

Know the various terms used to refer to HMI

  • HMI stands for Human-Machine Interface
  • MMI stands for Man-Machine Interface
  • GUI stands for Graphical User Interface
  • User Interface

What are the goals of HMI?

 a) To provide a machine which is operating effectively

b) To take feedback from machine to help the operator in taking decisions


Example of Car HMI

a) How does the vehicle give feedback to the operator?

The human, or the car driver in this case presses required buttons for certain functions. The machine i.e the vehicle in this case responds to the actions given by the user. In response to the actions performed by the user, the vehicle gives feedback which can be visual, auditory or movement in case of car.

b) How does this feedback aid the driver in making decisions?

Feedback helps the operator in efficiently performing any required task. For ex, for changing a song, the feedback will be given on the touchscreen now available in cars. It provides the driver with confirmation that certain task has been performed. It also helps in additional functionality.

c) How does the overall design of the HMI help the driver to effectively operate the vehicle?

The HMI provides the driver with all the necessary inputs like buttons, touchscreen display, gears and other controls. It helps to simplify the complicated operations. The operator feedback makes it easier for the user to operate. Thus efficiency is increased.


 Give practical examples of the following HMI concepts:

a) Look and Feel - The example for this would be when humans use computer, the interface of the computer provides a  look and feel about itself which improves the human - machine interaction. Different operating systems have different tabs, design and location.

b) Usability - Similar to above, usability refers to how easy or complex a machine can be for the human user to handle. Different operating systems are designed for various uses and thus usability changes. For ex, Windows operating system is mostly considered to have the most user-friendly interface i.e its usability is better as compared to others.

c) Accessibility - It tells how easily any machine /system is available to the end users. A good example for this would be when Nokia developed Windows smartphone, it lagged behind Android smartphones because the accessibility of the applications was far less as compared to Android.

What is” perceived affordance”?

Affordance are the possible actions an object/system can do. Perceived affordances are what a user perceives the system can do. It might be right or wrong.

Example: Consider a door open inwards. It has no door knob or signifier. The perceived affordance in this case would be that the door may open inwards or outwards.

Why is knowledge of HMI necessary when interacting with PLCs?

HMI consists of components, machinery required to make the system operate. Further it also includes necessary sensors required to monitor certain parameters. PLC is Programmable Logic Controller which gets the data from these sensors. It further converts this data into logical combinations. This is done so that the system can interact with people for different purpose like configuration, programming, alarm reporting, everyday control.

The HMIs vary from simple to complex for PLC. The types are:

  • Simple button and lights
  • Text displays
  • Graphical Touch Screen
  • Complex programming/monitoring software installed on a computer with PLC connected via communication interface

PLCs are computer embedded electronics devices to control and automate machine production lines etc. The unique approach of Unitronics combines both the control and HMI controllers in one PLC. This reduces hardware costs and programming time. It eliminates the need to build another PLC HMI communication unit. These PLCs include onboard integrated input/output. It enables one single unit to carry various operations.

These operations include 1)Process control-  process control application which constantly reading analog values and generating required response 2) Motion control -  motion control positioning of data 3) SMS communication- cellular connectivity generates immediate SMS and GPRS for reporting problems thus providing bi- directional and efficient communication with the operator anywhere.

Unitronics programming abilities include – sophisticated time based functions, closed PID loops, use of maths during application programming and data tables. These PLCs can be remotely programmed and controlled for operation of HMI using internet, ethernet and cellular networks. Applications for PLCs can be developed without any previous knowledge of programming. It can be done one single graphical interface. After development, the PLC is mounted on the control cabinet to carry its tasks.

It also provides graphical interface to the operator. PLCs provide high quality, reliability. Unitronics includes departments pertaining to planning, engineering, software, purchasing, production, training, service and support.IT believes in excellence and their slogan is ‘Committed to excellence’.