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Consider the General Notes on the Information in the Pepperl+Fuchs Product Catalogs
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Copyright Pepperl+Fuchs
16.08.12
Logic Control Units
Logic Control Units
9
•
No setting function or just a reset function to prevent adjustments
from being made
•
Very easy and clear operation with limited functionality
•
Menu-driven operation with a high level of flexibility for the
application.
•
These requirements are fulfilled in this order by the series:
•
KCM (no adjustment option)
•
KCY (simple adjustment of preset values using one button per digit)
•
KC-L and KCT (menu-driven operation and connection via
RS232‑interface, keylock can be activated).
9.2
Tachometers
Tachometers are pulse-controlled time measurement devices.
In contrast to standard tachometers (KCT Series) that count
the incoming pulses within a gate time, TC-type tachometers
evaluate the duration of a period between two subsequent input
pulses (cycle method).
The period duration is allocated an adjustable multiplication
factor and is converted into a rotational speed or speed
depending on the operating mode.
Benefit:
The cycle method requires only one pulse per revolution and a
maximum of two revolutions to detect the rotational speed with
high accuracy.
Rotational speed = 1/T x 60 min
-1
T = time between two pulses
min-1 = revolutions/minute
9.3
Sensor End Stages
Sensor end stages form the interface between the sensor
and the system controller or actuator if the output signal of the
sensor cannot be further processed directly. This is the case,
for example, where a two-wire sensor with NAMUR interface
must directly switch a load.The sensor obtains its power supply
from the sensor end stage, which also monitors the line if
necessary. The sensor end stage evaluates the sensor circuit
and switches its output accordingly. Sensor end stages are also
useful for connecting three-wire sensors. For example, if the
current load for the sensor-specific end stage is insufficient for
the connected load, or if a semiconductor output needs to be
converted to a potential-free relay output.
9.4
Rotation Speed Monitors
Rotation speed monitors are devices for displaying and
monitoring periodic signals, i.e., frequencies in general and
rotation speeds in particular. Periodic signals occur in almost all
areas of automation and process technology.
The input signals are evaluated depending on the cycle method,
i.e., through period duration measurement, and are converted
into frequency or rotational speed by a very quick microcontroller.
Particular
attention
was
paid
to
rotation
speed
monitoring during the development of these devices.
Displays and data can be provided in either Hz or
1/
min. It is also possible to automatically apply the actual rotation
speed of the drive for applications with slow processes. For this,
several pulses per sensor revolution can be converted into the
rotational speed using an appropriate setting.
The monitoring function operates using a trip value for which the
upper and lower hysteresis value can be freely selected within
the respective measurement and display range. The output
signal is generated when the predefined limits are exceeded or
not met.
In addition to the ON delay and OFF delay, pulse function, and
OFF delay timer, it is possible to select the direction of operation
for the output, i.e., for underspeed or overspeed monitoring. A
built-in start-up override prevents false signals during start-up of
the monitored system.
All common two-, three-, or four-wire proximity switches and
incremental rotary encoders can be used as signal sources.
Terminals are also available for connecting proximity switches in
accordance with DIN 19 234 (NAMUR).
9.5
Frequency Voltage
Current Converters
Frequency voltage current converters function in the same way
as rotation speed monitors. The difference is that a voltage or
current value that is proportional to the input frequency is emitted
as the output signal:
•
0
V ... 10 V
•
2
V ... 10 V
•
0
mA ... 20 mA
•
4
mA ... 20 mA
The pulse output provides the input frequency divided by an
adjustable factor (1 to 1200) for further processing.
