Rack Monitor 8800E/8801E
Document: Operation Manual
Date: 16-Jun-2011
Version: A.6
Page 20 of 35 H71343
Sensor detection.
The 8800E and 8801E rack monitor is an auto switching rack monitor and will detect automatically the 3 types
commonly used overfill sensors. Before the rack monitor switch to permissive the following steps will be performed.
1. Individual short detection between sensors and ground.
2. Resistive ground detection via pin 9
3. Ground bolt detection via pin 9
4. Sensor type detection
5. Detected sensors complies to EN13922
6. Detected sensors complies to Rest Of the World specifications (ROW)
7. Detected sensors appears to work but not complies to the above specifications.
Note: Overfill sensors commonly used in industry are not necessary compatible with commonly used Rack
Monitors in industry.
The specification of the ROW overfill sensor are based on an extensive worldwide sensor collection. All
parameters of those sensors are collected and the boundaries are stored in a table inside the 8800E/8801
Rack monitor
.
Note: The European Standard EN13922 describes the following points.
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Functions
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Major components
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Characteristics
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Test methods
Note: in some cases the rack monitor is still able to use the connected sensor as an overfill detection device. The
operator will be asked to accept the detected sensor by using the Blue bypass key.
Step 1.
In this step the rack monitor is checking if all wires are connected to a sensor and there are no shorts between
channels.
E.g. If on the tank truck one sensor is connected to two pins on the socket or one dummy channel is used to
emulate two dry sensors the Rack monitor will detect this as a short and show this on the LC-Display.
Step 2. & 3
Although ground verification is continues it is mention in this document as a step.
Since many Tank-Trucks are equipped with a ground bolt the 8800E/8801E Rack Monitor will accept this
automatically as a proper ground verification.
Be aware that conform the EN13922 in combination with Five-Wire sensor(s) the earth verification is
connected in series with the vapour recovery hose interlock switch
Step 4.
The Rack monitor will apply power to the sensor and analyze the measured signal.
In case of a Two-Wire Thermistor sensor, a special algorithm will be used to heat the sensor to his operating
temperature. This will be shown on the LC-Display with a H at Line 7
Also the Green LED indicator will change intensity until operating temperate is reached.
Note: Time to heat the sensor depends on ambient temperature and used Thermistor type.
07
S E N S O R
S T A T E
:
H H H H H H H H
If no Two-Wire sensors are detected, power will be applied at channel 8 and a pulse will transmitted at pin 4
If a return pulse is detected the rack monitor will continue with Five-Wire senor(s).
