System Architecture

There are three hierarchies in NCS4000 system: upper management (HMI), controller and field devices. The field devices include fieldbus sensor, fieldbus transmitter, fieldbus converter and 4 - 20mA instrument. The following Figure 2 illustrates NCS4000 system architecture hierarchy.

Figure 2 NCS4000 System Hierarchy

NCS4000 system consists of NCS4000 controller, workstation, and field device and control network. At the most one NCS4000 segment includes 32 NCS4000 controllers. And the NCS4000 workstation is industrial control computer; there should be less than 222 workstations in one NCS4000 segment in principle.

A NCS4000 system structure is shown in Figure 3.

Figure 3 A NCS4000 System Structure

1)  NCS4000 controller: As an industrial control device, NCS4000 controller performs collecting the field data, operation controlling, network communication and device diagnose and maintenance. It is composed of controller module, power module, I/O subsystem and other additional components. NCS4000 controller is the kernel of NCS4000 system.

2)  NCS4000 workstation: As a normal computer, NCS4000 workstation performs control strategy configuration, HMI display and history data recording.

3)  Necessary network devices: i.e. switcher.

4)  Control network: HSE (or EPA) standard.

Controller Hardware Architecture

NCS4000 system provides full distributed control function. By using the HSE (or EPA) control network, the NCS4000 controller in the network can fulfill real-time communication to achieve a control loop.

NCS4000 controller consists of controller module, power module, I/O subsystem and other additional components, as shown in the following Figure 4:

Figure 4 Hardware Architecture Of NCS4000 Controller

1)  Controller module: In the NCS4000 controller, the unit that updates and processes the field I/O data, executes the control arithmetic and communicates on the network, is called NCS4000 controller module. Two CPUs are used in controller module: one is used to manage I/O module, identify I/O and data output; other is used to execute control arithmetic, communicate and process the protocol. At most 255 control processes are supported, and up to 5000 function block can be executed, additionally, hot plug and device redundancy are supported.

2)  I/O subsystem: I/O subsystem provides the access to the field I/O signal, and consists of various types of I/O module, I/O terminal block and I/O backplane.

　 •  I/O backplane: I/O backplane uses passive serial bus. It is the data exchange channel for NCS4000 controller module and I/O module, and provides the operation power for I/O module. I/O backplane is designed to support the hot plug of I/O module. I/O backplane provides several communication baud rate, and supports high speed update rate for discrete input, as fast as 1ms.

　•  I/O module: I/O module can connect almost all field signals, such as 4 - 20mA standard industrial signal, discrete input signal, RTD signal and TC signal. I/O module also includes fieldbus communication module that is used to connect the fieldbus to NCS4000 system. Now NCS4000 system supports FF H1, HART, Profibus DP and Modus fieldbuses. In addition, I/O module is designed to be self-diagnosed for the convenience of diagnose and maintenance.

　•  I/O terminal block: I/O terminal block is the connecting point for the field signal. Now the termincal block can connect 8 channels and 16 channes signal. It is also support redundancy.

3)  Power module: The power module of NCS4000 controller is 1+1 redundancy. The input power is 24VDC, and output power is 20W. The power module is hot plug and has over-current output protection, over-voltage output protection and panel diagnose.

4)  Additional components: The additional components of NCS4000 controller include extension line, left extender and right extender. The I/O subsystem of NCS4000 system can be extended by extension line, which is 10 meters at most.

In NCS4000 system 32 NCS4000 controllers are supported and there are 4 I/O subsystems (can be upgraded to 8) in one controller. Each I/O subsystem contains 8 I/O modules, and each I/O module may have 8 or 16 I/O channels.

The system can be extended by the fieldbus communication modules.