Hey there! As someone just starting out with servo systems, I totally get how overwhelming it can feel. You're basically trying to solve three puzzles at once: matching your PLC's communication protocols, finding compatible drives, and sizing everything correctly for your mechanical load. Let me break this down in a practical way.
First, focus on your PLC's communication protocol - this is your starting point. Most modern PLCs support EtherCAT, PROFINET, or EtherNet/IP. Check what your specific PLC brand supports, then look for servo drives that speak the same language. Many drives today support multiple protocols, which gives you flexibility.
For mechanical sizing, don't get lost in complex calculations right away. Start with the basics: what's your load's weight, how fast does it need to move, and what's the required precision? Aim for an inertia ratio between 1:1 and 10:1 (load inertia to motor inertia) - this is the sweet spot for most applications.
My best advice? Talk to application engineers from reputable servo manufacturers. They can help you match components and avoid both overspecifying (which wastes money) and underengineering (which causes reliability issues). Also, consider using integrated servo systems where motor, drive, and communication are designed to work together - they simplify compatibility headaches dramatically.