Siemens SIPROTEC 6MD665, Manual, Page: 17 / 222

1.1 Overall Operation
3
6MD665 Manual
C53000-G1876-C103-3
Microcomputer
System The control functions and the measurement quantities are processed in the microcom-
puter system
µ
C. They especially consist of:
• Control of command outputs,
• Decision for close commands,
• Processing of indication inputs,
• Storage of annunciations, fault data and fault values for fault analysis,
• Control of signals for logical functions,
• Filtering and conditioning of the measured signals,
• Continuous monitoring of the measured quantities
• Monitoring the communication with other devices,
• Querying of limit values and time sequences,
• Management of the operating system and the associated functions such as data
recording, real-time clock, communication, interfaces, etc.
Analog inputs
(optional) The measuring inputs (I
Lx
, V
x
) convert the currents and voltages coming from the
transformers and adapt them to the level appropriate for the internal processing of the
device. The device has 3 current and 4 voltage inputs.
The current and voltage inputs can be used separately for measured value acquisition.
Within the scope of configuration, one- or three-phase evaluation functions are avail-
able for evaluation of the analogue inputs and evaluation after the Aron connection.
With voltage inputs, both phase-earth and phase-phase voltages can be applied. In
addition to a three-phase system, another reference voltage for synchronisation tasks
or a displacement voltage V
n
can be measured via the fourth voltage input.
Furthermore, two measuring transducer inputs are available.
The analogue values are transferred further to the IA input amplifier group.
The input amplification IA stage provides high-resistance terminations for the ana-
logue input quantities. It consists of filters that are optimised with regard to bandwidth
and processing speed.
The analogue-to-digital (AD) stage consists of a multiplexor, an analogue-to-digital (A/
D) converter and memory components for the transmission of digital signals to the
microcomputer system.
Binary Inputs and
Outputs Binary inputs and outputs from and to the computer system are routed via the I-/O
modules (inputs and outputs). The computer system obtains the information from the
system (e.g remote resetting) or the external equipment (e.g. blocking commands).
Outputs are, in particular, commands to the switchgear units and indications for
remote signalling of important events and statuses.
Front Elements With devices with integrated or detached operator panel, information such as mes-
sages related to events, states, measured values and the functional status of the
device are provided via light-emitting diodes (LEDs) and a display screen (LCD) on
the front panel.
Integrated control and numeric keys in conjunction with the LCD facilitate local inter-
action with the device. Via these elements all information of the device such as con-
figuration and setting parameters, operating messages and measured values can be
accessed. Setting parameters may be changed in the same way.
In addition, control of circuit breakers and other equipment is possible from the front
panel of the device.