Controllers offer enhanced Profinet functions
Siemens has expanded its Simatic S7-300 and S7-400 portfolio of mid-range controllers with new models and improvements such as new firmware, enhanced Profinet functions and integrated Web servers. The enhanced Profinet functions include Shared Device, Intelligent Device (I-Device) and Media Redundancy Protocol (MRP). These are said to make it easier to configure systems, for example in failsafe applications, as well as supporting leaner and more versatile topologies with multiple networked controllers.
♦ With Shared Device, several Simatic controllers can access a Profinet I/O device, allowing both standard and failsafe CPUs to use the same distributed I/O system.
♦ I-Device allows I/O to communicate with higher-level or central controllers. Previously only hierarchical access from the central CPU to lower-level I/O devices was possible. I-Device also makes it easier to network controllers from different projects, for example, or to integrate Siemens controls in a network with controllers from other manufacturers.
♦ MRP increases plant availability in a redundant ring-type network using industrial Ethernet switches or the Profinet interfaces of the Simatic controllers and distributed I/O systems. If communications are interrupted in one section of the ring, only that segment is affected and the plant can continue to run, allowing maintenance and repair work to be carried out without time pressure. The MRP protocol ensures a reconfiguration time of less than 200ms.
The new firmware also provides improved diagnostic functions via user-definable Web pages and supports Profinet’s isochronous mode.
The S7-300 family now includes the 319-3 PN/DP CPU with more memory and a bit processing time of 4ns – 2.5 times faster than its predecessor. A new addition to the S7-400 family is the 412-2 PN/DP CPU aimed at less demanding applications.