Page 2 of 11
HAWKER ELECTRONICS LTD.
The user should read this manual prior to installation or commissioning.
1. PRODUCT OVERVIEW
The DC1 controller is for use with Hawker sensing electrodes for detecting conducting
liquids. The DC1 can be used with two electrodes to provide high or low level alarm or
with three electrodes to provide control between two levels such as for pump control.
The internal control relay provides volt free changeover contacts and can be set to
either energise or de-energise on the presence of liquid thereby providing a ‘fail to safe’
feature to suit either ‘filling’ or ‘emptying’ of a vessel. Three selectable time delays are
available and can be used to prevent erratic operation due to wave motion, turbulence
or for general time delay applications.
2. OPERATING PRINCIPLE
The controller employs sophisticated circuitry that converts DC to low voltage AC
signals for the electrode circuits. The level controller senses a change in the electrode
signals when the measuring electrodes are touched by an electrically conductive liquid.
Using low voltage AC prevents corrosion of the electrodes (electrolysis) and the low
voltage ensures electrical safety. The electrode circuits are isolated from the users
power supply.
3. MOUNTING, ELECTRICAL INSTALLATION AND CONNECTION
The product contains no user serviceable parts. The product should only be installed
and used by suitably qualified persons, or those who have relevant experience. The
product should be installed in line with national and or local regulations.
Two versions are available: The DC1/P which is DIN rail mounting and DC1 which is
supplied in a wall mounting enclosure. When using the DC1 the user must fit suitable
cable glands for the application. Care should be taken when drilling the cable gland
holes so as not to damage the electronic circuit or enclosure.
An air gap of 5mm minimum should be left around the enclosures outer perimeter for
proper air circulation to prevent overheating. It is recommended that the input supply is
sourced via a suitably fused isolator located near the product. If the user is switching
hazardous voltages through the product’s output relay contacts e.g. mains 240VAC this
should also be isolated and fused locally. Maintenance is not required for this product
other than periodic testing if demanded by the application. Cleaning can be performed
using a mild detergent and care should be taken not to clean the product with
aggressive substances that may damage the enclosure, terminals or labels. Cleaning
should be performed with the power disconnected; the unit should be completely dry
before power is reapplied.
The product should not be mounted close to heat sources; electrically noisy apparatus
e.g. welding machines and inverter drives; locations subject to strong vibrations or
shocks; dusty or corrosive gas environments; outdoors in direct sunlight or high
humidity areas.
