Home > Siemens SIMATIC S7-300 PLC automation controllers available from CNC Design

Siemens SIMATIC S7-300 PLC automation controllers available from CNC Design

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article image Siemens SIMATIC S7-300 PLC automation controllers

To be able to automate the machines and plants economically and flexibly, customers need optimum solutions for every application area. Whether customers want control only or they also want to implement other automation tasks such as operator control and monitoring, technology, motion control or data archiving, CNC Design always have the right PLC solution for them. CNC Design also provide it with integration in engineering, communication and diagnostics.

The modular Siemens SIMATIC S7-300 PLC automation controllers, available from CNC Design, are optimally designed for control tasks and for ruggedness and long-term availability. They can be flexibly expanded at any time through plug-in I/O modules, function modules and communications modules. Depending on the size of the application, the right controller can be selected from a large range according to performance, quantity frameworks and communications interfaces. The modular controllers can also be used as fault-tolerant or fail-safe systems.

For creating the user programme, the three basic languages statement list (STL), ladder diagram (LAD), and function block diagram (FDB), and the high-level languages structured text (ST) and sequential function chart (SFC) are available. They comply with IEC 61131-3 and are used worldwide as an international standard.

The SIMATIC S7-300 PLC automation controllers have been designed for innovative system solutions with the focus on manufacturing engineering, and as a universal automation system, it represents an optimal solution for applications in centralised and distributed configurations such as, the ability to integrate powerful CPUs with Industrial Ethernet/PROFINET interface, integrated technological functions, or fail-safe designs make additional investments unnecessary.

SIMATIC S7-300 PLC automation controllers can be set up in a modular configuration without the need for slot rules for I/O modules. There is a wide range of modules available both for the centralised and the distributed configuration with ET200.

The micro memory card as a data and programme memory makes a backup battery superfluous and saves maintenance costs.

In addition, an associated project, including symbols and comments, can be stored on this memory card to facilitate service calls. The micro memory card can also be used during operation for storing and accessing data, e.g. for measured value archiving or recipe processing. In addition to standard automation, safety technology and motion control can also be integrated in an S7-300 together with SINAMICS S120.

Depending on the type of Siemens automation controller S7-300 CPU, various high speed counters are available up to 60kHz. They are used for counting and frequency measurement with incremental encoders. The compact CPUs also offer pulse outputs for pulse width modulation for direct activation of valves, final controlling elements and switching devices. The CPU’s are also equipped with integrated control blocks that do not reserve any space in user memory.

Positioning tasks can be solved comfortably in the CPU with the compact CPU 314C. The positioning algorithm for traversing an axis relatively or absolutely according to the rapid traverse/creep speed principle is integrated into the operating system of the CPU. They can be combined with onboard I/Os for simple closed-loop control tasks. A 24V incremental encoder can be connected as the position measuring system. Set points can either be output over 4 digital outputs or one analogue output ±10V.

Standard PID control is a pre-configured controller structure that is easily adapted by connecting or disconnecting functions to and from the control process. Standard PID control is implemented wherever small or medium-scale closed-loop control tasks arise: in temperature control, pressure control, flow control as well as fill-level control. Standard PID Control is particularly suited to applications that have been automated with compact controllers until now.

Standard PID Control contains the following pre-configured examples:

  • Step controllers with line simulation
  • Continuous-action controller with path simulation
  • Multi-loop ratio controller
  • Mixture controller
  • Cascade control

Cam controllers are implemented to activate position-dependent or time-dependent functions. They are far superior to mechanical cam controllers, due in particular to their high flexibility, for example, changes can be implemented by software means during normal operation.

Technology controllers are implemented for technology functions and are a low-cost solution for up to 32 axis. The integrated motion controller provides additional computing power with which comprehensive motion control tasks can be solved with high performance. Parameters are set with S7 Technology, an option package of STEP 7. A block library is available for programming that contains function blocks according to PLCopen. Interfacing to the drives takes place over an additional integrated PROFIBUS interface DP (DRIVE). This provides transparency from HMI through to the drive parameters.

Following are the benefits of technology controllers in the SIMATIC S7-300 PLC automation controllers:

  • High performance with motion control tasks
  • Parameter assignment and programming in the familiar STEP 7 environment
  • Efficient programming with ready-to-use function blocks according to the PLCopen standard

In combination with the PLCopen-compatible motion control blocks, the technology controllers are particularly suitable for coupled motion sequences of multiple axes. Along with position-controlled single axis positioning, primarily complex, synchronised motion sequences are possible, for example, geared synchronous motion, curve synchronization and print-mark correction. The synchronous axes can be coupled to a virtual master or a real master.

The SINAMCIS S120 AC drives have a CU310 control unit to couple them to the S7-300 controller. They offer a functional scope extending from a basic speed controller up to extensive positioning functions. Either a CU310 DP with PROFIBUS DP port or CU310 PN with integrated PROFINET port can be selected. Drive-related inputs/outputs can be connected to the CU using BICO technology. This permits the highest possible decoupling between the drive and the S7-300. Also for the AC drives, when necessary, an additional encoder and drive-related I/Os can be connected direct to the drive.

For multi-axis applications with SINAMICS S120 the drive is coupled to a CU320 multi-axis control unit. The CU320 can control up to 6 axis and can be connected to the S7-300 either with PROFIBUS DP or optional PROFINET. SIMATIC S7-300 PLC automation controllers control complex automation tasks with simple motion control.

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