Danfoss ECL 2000 User Manual page 97

PI controller
Pt 1000
Room influence
Service settings
Stand-by
Summer cut-off
Timer
Weather compensation
Proportional-integral controller. This is the method or algorithm that the ECL 2000
uses to control temperature. A PI controller combines:
•
A proportional controller, which provides fast control ensuring that the
controller's output signal is proportional to the measured process variable. The
effect of the proportional controller is determined by the parameter amplification
or proportional band.
•
An integral controller, which helps remove any constant deviation of the process
variable from the desired value (the setpoint). The parameter integration time
determines the effect of the integral controller.
Temperature dependent resistance: 1000
approximately 3.8 /K.
This facility allows the controller to reduce or increase the flow temperature in a heat
circuit if the room temperature exceeds a user-defined maximum or minimum.
The service settings are a number of parameters that determine how the ECL 2000
functions. The service settings can be displayed and modified via the controller's
service menu.
In this operating mode, automatic control of heat and hot-water circuits is disabled.
However, the controller constantly monitors the flow temperature in the circuits.
Should the flow temperature drop below 6 °C, the controller activates heating in order
to avoid frost damage.
This facility enables the controller to close down a heat circuit when the outdoor or
room temperature exceeds a user-defined level.
The ECL 2000's timer function enables the controller to switch on and off some
external device, according to a user-defined 7-day, 24-hour plan.
A facility that enables the controller to take outdoor weather conditions into
consideration for heat circuit control. In the ECL 2000, this facility is based on a user-
definable weather compensation curve which determines what the flow temperature
should be when the outdoor temperature varies. It is possible to set up weather
compensation curves for flow and return temperatures in heat circuits.
EY.65.H4.02
at 0 °C. The resistance varies by
Glossary
91