I’m an industry service engineer for food packaging machines rather than an automation specialist, however can give you few hints.
For all those automation systems to operate, you must first have a very clear and detailed mechanical plan with all of details finalized. Whenever you do this, you have to specify the type of motions involved, e.g.: linear or rotary. This lets you be aware of number and kinds of motors and actuators you’ll need(servo, ac single phase, ac 3 phase, pneumatic actuator).
For each and every 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(much more conveyors, liquid tank level control pumps or rollers).Servo motors need Servo drivers to manage their precise movement.
These are your output devices, you will need your input devices to become lay out. This is level sensors, flow sensors, proximity switches and also other devices as required. The key reason why i’m stating out this routine is to enable you to define the specifications essential for your control system hardware requirements. All PLC manufacturers layout their product line-up according to system complexity.
Most PLC hardware is sold as reconfigurable rack chassis. Basically you have the CPU which is the master brain that’s supplemented with I/O device which can be slotted in like cards. Additional complex systems which needs servo motor could have servo card in order to connect 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 workout you IO devices list, then obtain the necessary hardware and software needed. You will need additional hardware required for for fancy touch screen HMI, line automation and online diagnostic and asset monitoring functions. That’s that the guy with mechanical background can approach complex automation problems.
The solutions could differ according to different manufacturer offering especially if you use beckhoff based systems. A good way to start can be to work with existing machines so that you will study the basics. Then go obtain a few catalogs from reputable manufacturers to understand the marketplace has to offer. I suggest website visitors to go through Omron catalogues. There is also a totally free automation web based course which will show you the newborn steps needed.
You need 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 to some additional training on the more knowledge about each piece of equipment, regarding how to program or properly connect them, but it is not brain surgery, a good mechanical engineer should probably excel about this as any other engineer. The most important element of control system design would be to see the process you will control and the goals you need to achieve.