Sunday, February 13, 2011

Hardware of XC600 PLC

The XC600 PLC has a modular design. The basic unit consisting of the base, power supply, CPU and operator modules can be expanded with function modules for communication. Modules for the standard PROFIBUS-DP and CANopen networks are therefore provided for this purpose. They provide the controller with access to the I/O devices that log process data signals and control actuators.

The process signals can also be connected locally with XI/ON Input And Output modules. This requires the use of the power supply module with the integrated XI/ON interface and the base module with the XI/ON adapter. A module consists of a circuit board that is embedded in a frame. The special frame design makes it possible to stack the modules together, thus allowing compact functional units to be combined to suit the requirements of the task at hand.

The circuit boards of the individual function modules meet the requirements of the PC/104+ specification. In addition to dimensions, the specifications also stipulate the requirements of the PC/104+ bus that connect the modules. This bus also carries the power supplies from the power supply module to the individual function modules.

A configuration containing XI/ON input/output modules must always include the XC-ADP-XION base module with theXC-POW50-XION-UPS power supply module. The power supply module adapts the PC/104+ bus to the XI/ON module bus using the XI/ON interface. This bus is connected out from the base module. The adapter on the base module provides the interface to the XI/ON modules. The 24 V DC field power supply of the XI/ON modules is also connected to the base module.

Control cabinet design
The arrangement of components in the control cabinet is an important factor in ensuring that system and machine functions are free of interference. During the planning and design stages, as well as during implementation, it must be ensured that the power and control sections are separated. The power section includes the following components:
• Contactors
• Coupling modules
• Transformers
• Frequency inverters
• Current converters

Dividing the control cabinet into to areas with different power and interference levels is recommended as an effective prevention against electromagnetic interference. In small control cabinets, this can often be provided sufficiently by using separators in order to reduce interference.

Ventilation
A minimum gap of 5 cm between passive components must be provided in order to ensure sufficient ventilation. If active components (e.g. load power supply, transformers) are fitted next to each other, a minimum gap of 7.5 cm must be ensured. Observe the values specified in the technical data.

Switching the power supply on/off
The UPS ensures that the XC600 controller is switched off properly in the event of a power supply failure. This requires the inputs/ outputs of the UPS device and the other devices to be wired. If the supply voltage to the UPS device drops, the controller is supplied with the battery supply voltage. The contact ”C1” in the UPS device opens and the circuit at the Power Fail input of the power supply module is interrupted. This will cause the controller to initiate the PFI signal, which will cause the system to shut down. The controller requires around two minutes doing this.

By connecting the Battery off input of the UPS to contact C2, the UPS device can switch off the battery supply voltage after two minutes. The battery is then used only for these two minutes so that further battery backup protection is ensured occur. If power is restored after two minutes, the controller will start up again according to how the operating mode selector switch is set.

A different routine is followed if the power supply to the UPS returns within two minutes: while the power to the UPS device has failed, the controller is at first initially supplied by the battery voltage until power is restored. As the UPS device signals the power failure to the controller (Power Fail input), the controller starts a system shutdown (2 minutes). The following message will be shown on the display: ”PFI shut down in progress”. The operation ends with the message”TURN OFF YOUR CONTROLLER” on the display.

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