4
Installation and Operating Manual
IP227, Rev DA
Mobrey MCU200 Series
February 2020
1.
Introduction
Delta-Mobrey level control systems for sludge blanket and interface detection applications
require a Mobrey MCU200 Series control unit and a Mobrey ultrasonic sensor (
Figure 1
).
The start of this manual shows how to install the control unit and supported sensors to form
control systems. This is followed by application information for configuration and operation of
the control unit. Finally, there is the maintenance, spare parts, and specifications information.
Figure 1. Typical application with Mobrey 442SD and 402SD ultrasonic Gap Sensors
A. Mobrey MCU200 controller
B. Mobrey 402SD sensor
C. Mobrey 442SD sensor
2.
Sensor installation
2.1
Safety matters
Review all the safety information at the front of this manual.
2.2
How ultrasonic gap sensors work
Each Mobrey ultrasonic sensor contains two piezoelectric crystals. A high frequency signal
(1 MHz or 3.7 MHz) is generated by the control unit and transmitted to one of the piezoelectric
crystals by coaxial cable. This crystal converts the electrical signal into an ultrasonic oscillation.
The sensor design allows the ultrasonic oscillation to pass from the transmitter crystal to the
receiver piezoelectric crystal (
Figure 2
) through a gap. When the gap is in liquid, the signal
reaches the receiver due to the low ultrasonic attenuation of the liquid. When the gap is filled
with air, no ultrasonic signal can pass from transmitter to receiver.
A
B
C
