KROHNE OPTISENS OAM 2080 EN - Manual (Page 11)

DEVICE DESCRIPTION
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OPTISENS OAM 2080
www.krohne.com 08/2010 - MA OPTISENS OAM 2080 R01 en
Main electronics unit
The main electronics unit is located at the front door in a separate enclosure. It controls all
mechanical events in the device and communicates with both the sensor and the converter. The
communication with the converter is done through a RS-485 interface.
Other signals going in and out of sludge blanket meter are also conducted to the main
electronics unit. The unit collects the values of the sludge concentration from the sensor and
transmits them to the converter.
Sensor
The sensor is connected to a cable that supplies the sensor with power. The cable also transmits
the communication signals to the pickup board.
The sensor contains a near-infrared light source and a receiver. Both are positioned in such a
way that the emitted near-infrared light has to pass through the liquid before reaching the
receiver.
Cable connection terminal
The separate box in the lower left corner of the enclosure contains the connection terminal for
the external wire connections. To the left of this terminal block there is a safety switch that will
disconnect the power when the enclosure door opens.
On the top of the terminal box there is an emergency motor control switch witch the functions
"Up" and "Down". It allows to control the sensor movement even if the normal control function
does not work.
Pickup board & axle board
The pickup board is mounted on a spring loaded lever arm and transfers power and
communication signals to the cable drum. It also measures the revolutions of the cable drum
with the help of sensors.
The axle board on the cable drum is powered contactlessly ("inductively") from the pickup board.
It communicates with the main electronics unit via the pickup board and with the sensor via an
optical RS-485 interface.
Heater & fan
The heater is located behind the drum mounting plate. Together with the fan it maintains a
stable temperature inside the enclosure of the meter. The position of the fan is on the top right
side of the enclosure.
.book Page 11 Friday, August 20, 2010 1:07 PM