We have been working on #Industry4.0 Implementation and Industrial automation for more than 4 years. We see that the requirements are continuously changing to have more control on the operation and at the same time the data need to be sent and managed from the central server.
Today in the traditional system, we have a #HMI which has some program running to ensure that the human communication is transformed to send commands to PLC for it to read from sensors and write to actuator interfaces. PLC programs are done to work in tandem with the HMI.
In our projects, we were able to read and write via Digital interfaces to get the automation done bye passing the PLC. I believe we will be able to achieve the same with the analog interfaces as well.
Why such smart IoT Devices will replace PLCs on the long run.
1. Data communication both the ways comes by default enabling centralized control.
2. No need for the local data or instructions anymore.
3. Devices has become robust as PLCs running 24 X 7 for years in Industrial conditions.
4. Most Important point- No need to do programming at two places.
5. The customizable functional blocks of PLCs will be replaced with NO CODE / LOW Code application being embedded into these devices.
This is something that will happen over the next 10 years. There is a equal chance of PLC getting evolved with much better sophistication and merge the HMI programming into its layer and HMI will be just displays and eventually become the current day micro devices.
My Post on Linkedin - https://www.linkedin.com/feed/update/urn:li:activity:7031122084877455360/
I totally agree IIoT has a place in the picture and can better perform many of the functions that a carried out using a PLC today.
I am fairly confident the PLC will not be replaced completely, due to a few things namely real time os, memory mapping, STL etc. I think its more likely as you say at the end of you post The PLC will evolve (and already is) to include many of the smart functions carried out by IIoT.