digistst

Thermostats

Thermostats or Digital Controllers
It is important that when considering heating any system you also bear in mind that you will need to control that water temperature accurately to avoid heat loss and larger than would be heating bills. With this in mind we offer an excellent Digistat Controller.
With any piece of equipment offered for sale at ERK we think it's a good idea to explain why you should make the decision to part with your hard earned cash...
A Thermostat is a simple negative feedback controller: when the temperature (the “process variable” or PV) goes below a set point (SP) the heater is switched on.
A very familiar everyday example is bringing a kettle of water to the boil in the shortest time, which is achieved by applying full heat, then turning it off when the water reaches a boil. A closed-loop household example is most thermostats, wherein the heating element or air conditioning compressor is either running or not, depending upon whether the measured temperature is above or below the setpoint...
In your pond application it means that the Digistat Controller maintains desired temperature by turning the applied power on and off (as opposed to continuously varying electrical voltage/current) this based on temperature feedback is an example application of bang–bang control. Although the applied power switches from one discrete state to another, the water temperature will remain relatively constant due to the slow nature of temperature changes in materials. Hence, the regulated temperature is like a sliding mode of the variable structure system setup by the bang-bang controller...

Pro-Line Digistat Controller

The Pro-Line Digistat Controller:
 
Digistat & Probe (Digital Readout, Very Accurate)
The Pro-Line
The Microprocessor-Based Digital Electronic ThermoController comes complete with an external probe.

Proline Probe

Available in lengths:

1.5M
3M
6M