Function & operation
This CPU handles the full feature set: the 32 kbyte input and 32 kbyte output process image sizes define the maximum I/O data that can be exchanged each cycle — enough for a mid-sized machine cell with several distributed racks. The single PROFINET port supports MRP (Media Redundancy Protocol) with MRP Automanager and MRP Manager roles per IEC 62439-2 Edition 2.0, plus MRP Client, enabling ring topologies for network resilience. MODBUS TCP is built in, so the CPU can talk directly to drives, HMIs, and third-party devices without an additional gateway. Up to eight communication modules or CPs (PROFIBUS, PROFINET, Ethernet) can be inserted via the backplane, extending connectivity beyond the onboard port. The RS-485 port on X3 provides a serial drop for legacy fieldbus devices or point-to-point links, while the PROFINET interface handles real-time motion control and I/O synchronization. The CPU supports IPv4, DHCP, DCP, LLDP, SNMP, and HTTP/HTTPS for standard and user pages, making it manageable in a modern IT/OT network.
Applications
The CPU 1516T-3 PN/DP is specified for machine and plant automation where deterministic motion control and high-speed I/O are required — packaging lines, printing presses, material handling, and assembly cells. Its MRP support suits ring-topology PROFINET networks in continuous-process plants where a single cable break cannot stop production. The MODBUS TCP capability also makes it a natural fit for retrofits where existing equipment speaks MODBUS.
Market & positioning
Within the family, the 1516T-3 PN/DP sits above the standard 1516-3 PN/DP by adding technology functions for motion control (the 'T' designation). It targets machine builders who need coordinated axis control without stepping up to the high-end 1517T or 1518T CPUs. The ability to insert up to eight communication modules gives it the flexibility to integrate PROFIBUS segments or additional PROFINET networks alongside the onboard port.
Lifecycle & availability
The 6ES7516-3TN00-0AB0 carries a RoHS compliance date of 19-01-18, indicating it has been in production for several years. No end-of-life or phase-out notice is recorded in the available evidence; the CPU remains an active catalog item from Siemens. Sourcing is through standard distribution channels; lead time and availability should be confirmed via RFQ.