Benefits to HMIs

Lots of pros listed here but none of the cons. HMI/automation suppliers (myself included) will tell you that it is simpler to operate but it is not in our interest to mention that deskilling your plant/process operators is not generally a good thing. I have encountered situations where I can hear a gearbox whine and obviously about to fail but the operator ignores the sound because his HMI does not show that there is a fault. Warn users that HMIs, SCADA' IIoT, industry 4.0 and automation supplement controlling the equipment but will not and can not replace the eyes and ears of a trained operator.

There are situations to employ HMIs and situations where it is a poor option. Many modern compressors have an HMI installed. It tells the user if the oil is too low or the temperature is too high and how many hours remain to the next service. The advanced electronics of the HMI is less reliable and more expensive than the two light bulbs and the hours run counter that it replaced. The oil and temperature sensors remain unchanged. The thermal overload relay cuts out the motor and then informs the HMI that the motor has tripped. The soft buttons on the screen are more prone to vibration faults than the replaced hard start/stop buttons, and the Emergency Stop still has it's own dedicated circuit that bypasses the HMI.

Then there is the flip side to that argument: well-trained operators can free up some time to make additional rounds where they actually check equipment, appearance, sound, smell, etc. Maybe even shoot an IR temperature here and there.

The HMI makes it easier to keep the logs up to date, and can help in start-up and shut-down mode a lot by allowing the operator to see what is happening on a number of pages nearly instantly, and he does not have to walk over to that piece of equipment to see how it is behaving at the moment.

Poorly designed HMI's are not the fault any more than guns are at fault for killing people. The fault with HMI's comes from failing to describe sufficient details in the begining. Just like most PLC programs that barely accomplish the task.

Good diagnostics have to be built in or added after the initial installation. Only smart people get around to doing that. That is where the shortage comes from.

Advantages of HMI Touchscreen

Visualization: What can the operator pay attention to on the screen during the interaction with the machine during the shift, or what content is not paying attention to? These answers will affect how to overcome automation and process challenges, and how to deal with potential and costly mistakes. For example, research uses darker colors in most areas of the screen, and more vivid colors in unusual conditions, which can attract the attention of the operators.

Pattern recognition: The use of display mode increases the speed and accuracy of the operator's assessment of conditions. In the traditional interface, the operator needs to read and compare the values. Modern human-machine interfaces use patterns that people are more familiar with, so the display itself becomes information and requires less explanation.