德TURCK图尔克流量开关，NI12U-M18-AP6X-H1141
All sensing ranges of photoelectric sensors and excess gain
curves of retroreflective sensors mentioned in this catalog
were determined with the BRT75 reflector. Retroreflectors are
designed in such a way that light is reflected back in the same
direction. The amount of light reflected back to the sensor depends
on two factors:
1. The size of the reflecting surface
2. The reflector‘s reflectivity
Short distances require a reflector with Ø 25 mm which is capable
of reflecting the light as good as a Ø 75 mm reflector. A
Ø 75 mm reflector reflects up to nine times more light than a
Ø 25 mm and is suited for longer distances.
Refreshing rate
The period a value takes to be formed in an application in device
A, to be sent on line to a device B and made available to
the application there. The refreshing rate should not be confused
with the response time, which is slower in most cases. A
floating average value can be formed for a data volume of 10
ms and given out every 1 ms. In this case the refreshing rate is
1/1 ms resp. 1 kHz, while the response time is 6 ms.
Release point （pressure sensors）
In hysteresis mode, the output switches at the release point
（rP） when system pressure decreases. In window mode, the
output switches at the release point （rP） independent of
whether system pressure increases or decreases.
Is the time a sensor takes to react to a given change of an input
德TURCK图尔克流量开关，NI12U-M18-AP6X-H1141
signal. Exampel: A temperature sensor working at 0 °C is
instantly immersed in 100 °C hot water. After 4 seconds, the
sensor indicates 63 °C. The response time is thus 4 seconds.
Retroreflective sensors （photoelectric sensors）
Retroreflective sensors host both emitter and receiver circuitry
in the same housing. A light beam is established between the
emitter, reflector and receiver. An object is sensed when it interrupts
the beam. Retroreflective sensors share some advantages
with opposed mode sensors such as good contrast and
high excess gain. Moreover, only one device has to be installed
and wired. Of disadvantage are short sensing ranges
and objects with shiny surfaces when using devices without
polarizing filter.
Reverse polarity protection
Protection against false connection.
Ripple
Irregularities in the DC voltage may occur after the VAC mains
voltage is rectified to a VDC voltage （due to the original sinusoidal
wave of the mains voltage）. The remaining wave
troughs can be compensated （“smoothed”） by means of a capacitor
connected in parallel to the load or a coil connected in
series to the load. The remaining AC component after smoothing
is called the ripple or hum voltage. 10% ripple （peak to
peak） of supply voltage is usually tolerated.

德TURCK图尔克流量开关，NI12U-M18-AP6X-H1141