I’m a field service engineer for food packaging machines and never an automation specialist, but i can provide you with few hints.
For all automation systems to work, you have to first use a clear and detailed mechanical plan with all of details finalized. If you achieve this, you must specify the kind of motions involved, e.g.: linear or rotary. This lets you have in mind the number and kinds of motors and actuators you need(servo, ac single phase, ac 3 phase, pneumatic actuator).
Per motors you may need relay contactors (for single speed discrete/on-off type motors like blower fans and liquid pumps), VFD for speed controllable ac 3-phase motors(similar to conveyors, liquid tank level control pumps or rollers).Servo motors need Servo drivers to manipulate their precise movement.
These are generally your output devices, you will want your input devices to get put down. This is often level sensors, flow sensors, proximity switches and other devices if required. The reason why i’m stating out this routine is usually to allow you to define the specifications required for your control system hardware requirements. All PLC manufacturers layout their product line-up based on system complexity.
Most PLC hardware is sold as reconfigurable rack chassis. Basically you have the CPU which is the master brain which is supplemented with I/O device that could be slotted in like cards. Additional complex systems which needs servo motor can have servo card to get in touch with servo driver, communication bus cards like CAN-BUS, PROFIBUS and DEVICENET and sensor cards for special sensors like RTD temperature sensors and level sensors.
So work out you IO devices list, then get the necessary software and hardware needed. You may need additional hardware necessary for for fancy touchscreen technology HMI, line automation an internet-based diagnostic and asset monitoring functions. That’s the way a guy with mechanical background can approach complex automation problems.
The solutions could differ depending on different manufacturer offering particularly if you use beckhoff based systems. The best way to start may be to work on existing machines so that you can discover the basics. Then go obtain a few catalogs from reputable manufacturers to understand the market industry can give. I always suggest people to go through Omron catalogues. There is also a free of charge automation web based course which will educate you on the infant steps needed.
You have to be capable of design complete PLC systems: architecture design, hardware specfications and selection, logic narratives, logic programming, connection drawings. Everything. Perhaps you just need some additional training around the more knowledge about every bit of kit, on how to program or properly connect them, however it is not rocket science, a fantastic mechanical engineer should probably excel for this just like any other engineer. The main facet of control system design is always to comprehend the process you’re going to control and also the goals you would like to achieve.