Sensors Types
Two-Wire sensors.
Five-Wire sensors.
Sensors and Grounding
Before continuing describing the functionality of the rack monitor a short explanation of the sensors and ground
verification. As mentioned above there are three industrial standard sensor principals.
Thermistor sensors are not commonly used therefore the 88XX does not support this type of sensor.
To avoid misunderstanding this manual will refer to Two-Wire sensors (2-Wire) and Five-Wire (5-Wire) Sensors.
The sensing circuit of a 2 (and 5) wire sensor are not necessarily done with a optic detection circuit other detection
principles are also used.
Two-Wire sensors can be used on vehicles with no more than eight compartments. Standard Gantry controllers are
monitoring all 8 channels (see dipswitch setting for 6 channel US version). This means the remaining channel(s) on
vehicles equipped with Two-Wire sensors with less than 8 compartments must be connected to an electronic
Dummy (e.g. part number 1920). All sensors are individual wired / connected to the Rack monitor and more than
one wet compartment can be detected at the same time.
The Five-Wire sensors are connected in series and therefore capable of handling more than 8 compartments.
Because of this, only one wet compartment can be indicated at the same time. A special diagnostic wire is used to
determine the wet compartment. The 88XX can handle more than 12 compartments but only 12 will can be
indicated on the LED display. (Maximum 12 compartments according EN13922)
The 88XX will try to determine which compartment is wet if a good connection is made between plug and socket
and wiring are done carefully, the 88XX shall indicate the correct compartment on the Liquid Crystal Display.
Note: Displaying the correct wet compartment is only possible if there are no bad connections.
Ground verification is done via pin 9 on the terminal and plug-socket connection.
For NEN-EN13922 application pin 9 is also used for detecting if a Vapour recovery hose is properly connected to
the Tank-Truck when five-Wire sensors are used.
Note: The Vapor Recovery Hose is checked via pin 8 on a Tank-Truck equipped with Two-Wire sensors in
EN13922 compliant locations (only).
Note: Consult socket drawings for detailed information.
The 88XX Rack Monitor is capable of detecting a resistive ground connection as well as a Ground-Bolt (GS1000 or
GS1001) connection on a Tank-Truck. Make sure connection between pin 9 and pin 10 via the Tank-Truck chassis
is less than 1kΩ.
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