Appendix MSX-E3701-DIO
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.
Input level
The input level is the logarithmic ratio between
two electrical values of the same type (voltage,
current or power) at the signal input of any
receiving unit. This unit is often configured as a
logical level related to the input of the circuit.
The input voltage corresponding to logic “0” is
between 0 V and 15 V and the voltage
corresponding to logic “1” is between 17 V and
30 V.
IP degree of protection
The IP standard defines the degree of
protection of a system against dirt and water.
The first figure after the “IP” (e.g. 6 in IP 65)
indicates the degree of protection against solid
objects penetrating the housing. The second
figure indicates the degree of protection
against liquids penetrating the housing.
In IP 65, the figures 6 and 5 have the following
meaning: 6 = full protection against moving
parts and against dirt penetration;
5 = protection against jets of water from any
direction.
In IP 40, the figure 4 equates to protection
against contact with small objects and
protection against small foreign bodies (larger
than 1 mm). The figure 0 means that there is
no protection.
Level
Logic levels are defined for processing and
displaying information.
In binary switches, voltages are used for digital
values. Here, the two voltage ranges “H” (high)
und “L” (low) represent the information.
The “H” range is closer to plus infinity; the “H”
level corresponds to digital 1. “L” denotes the
range closer to minus infinity; the “L” level
corresponds to digital 0.
Limit value
Exceeding the limit values, even for a short
time, can easily result in the destruction of the
component or the (temporary) loss of
functionality.
MAC address
MAC = Media Access Control
This is the hardware address of network
components used to identify them uniquely
within the network.
Optical isolation
Optical isolation means that there is no flow of
electrical current between the circuit to be
measured and the measuring system.
Protective circuit
A protective circuit is set up on the actuator
side to protect the control electronics and
provide adequate EMC safety. The simplest
protective circuit involves connecting a resistor
in parallel.
PTC
= Positive Temperature Coefficient
The best-value resistance sensors are either
specified as PTC or NTC thermistors. A PTC
thermistor has a positive temperature
coefficient, hence, “PTC”.
Resolution
The resolution indicates how precisely a signal
or value is held within the computer.
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