KROHNE OPTISENS OAM 2080 EN - Manual (Page 20)

4
ELECTRICAL CONNECTIONS
20
OPTISENS OAM 2080
www.krohne.com 08/2010 - MA OPTISENS OAM 2080 R01 en
4.3 Connection diagram and grounding
4.4 Rake guard limit switch
To protect the sensor and cable from being damaged or destructed by rakes or other moving
parts, the meter has an N/O contact input for the connection of an external limit switch (you have
to buy this switch with another manufacturer). The sampling cycle will only start if this switch is
closed.
The function of the limit switch is to trigger the sampling process. When the moving device (e.g.
a rake) contacts the limit switch, the sampling process starts. You can define the number of
passes of the moving device that should occur before starting the sampling process with the
help of the converter (see "Trig" in the "Advanced setup" within the menu "Settings"). For
information concerning the electrical connection of a rake guard limit refer to the next chapter.
If there is no danger for the sensor or cable to be caught by moving devices (i.e. installation in
thickeners without stirrers), you can set an alternative sampling mode in the converter
controlled by the build-in timer. In this case you must wire the connections for the rake guard
switch to one of the converter relays (for further information see section "Relay outputs" in
chapter 4 "Electrical connections" in the MAC 080 handbook) and set a timer interval in seconds,
which triggers the sampling cycle accordingly (for further information refer to
Timer interval
(optional) on page 29).
1 Push-button (door open/closed)
2 Switch for manual hauling (up/neutral/down)
3 Spare I/Os
4 I/O for rake limit switch (24 VDC)
5 Power (live)
6 Power (earth)
7 Power (neutral)
CAUTION!
To avoid damages or destructions, use a limit switch in all applications where a rake or other
moving devices may come in contact with the sensor or cable! The manufacturer does not
assume any responsibility for damages caused by the absence or malfunction of the rake guard
limit switch.
INFORMATION!
Defining the interval of the sampling process is suitable when the position of the moving device
is well known (e.g. with surface rakes). If the moving device contacts the limit switch during
sampling, the sampling process stops and the sensor moves upwards.
.book Page 20 Friday, August 20, 2010 1:07 PM