Appendix MSX-E1516
6
Appendix
6.1
Glossary
Cascading
Cascading means connecting multiple similar
elements together to enhance their individual
effect. The individual elements must be such
that the outputs of a given element are
compatible with the inputs of the subsequent
element in terms of values and functionality.
Digital signal
A digital signal is a digital representation of a
constantly changing value or other piece of
information. Digital signals consist of a finite
number of values. The smallest possible
difference between two digital values is
referred to as the resolution. Digital signals are
discontinuous in terms of value and time
ranges.
EMC
= Electromagnetic Compatibility
The definition of the VDE regulation 0870
states: Electromagnetic compatibility is the
ability of an electrical installation to function
satisfactorily within its electromagnetic
environment without unduly affecting its
environment and the equipment it contains.
Ethernet
The Ethernet is a baseband bus system
originally developed in order to connect mini-
computers. It is based on the CSMA/CD access
method. Coaxial cables or twisted-pair cables
are used as the transmission medium.
The transmission speeds are 10 Mbit/s
(Ethernet), 100 Mbit/s (Fast Ethernet) and
1 Gbit/s or 10 Gbit/s (Gigabit-Ethernet). This
widely used technology for computer
networking in a LAN has been standardised
since 1985 (IEEE 802.3 and ISO 8802-3).
Ethernet technology is now common practice in
the office environment.
After making even very tough real-time
requirements possible and adapting the device
technology (bus cables, patch fields, junction
boxes) to the harsh application conditions of
the industrial environment, Ethernet is now
also increasingly used in the field areas of
automation technology.
Event
An event is an occurrence detected by the
MSX-E system. Where e. g. a short-circuit is
detected and an event is activated, a short-
circuit warning can be sent via the event server.
Ground line
Ground lines should not be seen as potential-
free return lines. Different ground points may
have small potential differences. This is always
true with large currents and may cause
inaccuracy in high-resolution circuits.
Hysteresis
Hysteresis is the difference between the start-
up and shut-down voltage. In TTL circuits, it is
typically 0.8 V; in CMOS circuits, it depends on
the supply voltage.
IEC
= International Electrotechnical Commission
The IEC is a UN body affiliated to the ISO
(International Standards Organisation) which
sets standards for electrotechnical parts and
components.
Input impedance
The input impedance is the ratio of voltage to
current at the input terminals when the output
terminals are open.
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