Product category:
Waste-water handling, monitors + treatment
News Release from: Hawker Electronics | Subject: DC1/P
Edited by the Processingtalk Editorial
Team on 26 April 2007
DC powered level controller for sewage
sumps
Hawker has always been considered a leader in conductivity level probes and controllers, and now introduce a DC powered level controller for use in conducting liquids
The classic Hawker detection circuitry has always relied on a low AC current passing through the conducting liquid, to cause the energisation of a relay Having an AC circuit is important, to ensure there is no electrolysis occurring on the electrodes
This article was originally published on Processingtalk on 10 May 2005 at 8.00am (UK)
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Generating AC from a DC source means that controllers can potentially generate electrical interference.
Hawker have overcome this problem and have still maintained their normal close switching differential, enabling the sensors to ignore electrode contamination and foaming liquids.
The DC1/P is very low powered, so could be operated easily from a solar battery used in a remote location.
It is fully isolated making it safe to use.
There is also a variable time delay for applications involving waves or surface fluctuations.
Principle of Operation.
The controller in conjunction with Hawker electrodes is used to detect the presence (or absence) of a conducting liquid in a vessel.
When the liquid is detected the DC1/P controller de-energises or energises a relay depending on the fail safe setting and provides the user with a set of volt free changeover contacts.
The unit may be used for pump control or for high or low alarms.
The DC1/P operates from 20-27VDC supply, reverse polarity protected, and generates a 10VAC supply to the electrodes.
The AC supply is critical to prevent electrode corrosion due to electrolytic action.
The DC1/P incorporates the unique Hawker circuit used on its conductivity operated controllers which allows operation in high earthy liquids such as foaming sewage with entrained solids, seawater and chemicals.
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