Additional technical information (COSY)

COSY functions in the same way as an electric light switch with the hose conducting electricity as part of a circuit as shown in the diagram. The principle relies on the hose couplings being electrically connected, but this condition is normally met in order to prevent the build-up of electrostatic charge.

Principle of operation

A control circuit is established with a hose as one of the condutors. When the hose is disconnected the circuit is broken. An electrical resistance prevents any significant flow of current into the installation.

COSY(T) in the loading bay

COSY(T) is used to monitor mobile tankers. It measures the resistance between the tanker and the fixed installation and can be used to monitor three types of connection:

• Product flow hose
• Vapour return
• Earth (ground) connection.

The 24V DC signal from COSY is used to switch an alarm or control relay.