Daikin EWWQC13AJYNN [60/130] Setpoint reset of the chilled water

Daikin EWWQC13AJYNN [60/130] Setpoint reset of the chilled water
Functional Control ESIE07-05
2–54 Part 2 – Functional Description
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2.4 Setpoint Reset of the Chilled Water
Introduction Among the MicroTech NC controllers options, there are also several possibilities to regulate the unit
with particular logics or outside signals. The setpoint reset function gives the possibility to modify the
local setpoint of the chilled water according to the following logics:
double setpoint
external signal
OAT (outdoor ambient temperature) reset
return water reset
Double setpoint Through an external contact (optionally a switch is installed on the electric panel control), it is possible
to vary the local setpoint of control between two well defined values. Such option results are
advantageously applicable in case of installation with ice bank. When the temperatures of evaporator
outgoing water are inferior to 4°C, the introduction of the correct quantity of Anti-freeze in the hydraulic
system is required.
External signal The setpoint override allows, by use of an external signal, to override the chilled water setpoint.
This function is activated by enabling the analog input B3 of the controller. A 4-20mA signal can be
used to change the setpoint.
For inputs lower than 4mA, the water setpoint is set to the local setpoint
For inputs between 4 and 20mA, the setpoint is obtained by linear interpolation between the
setpoint and the setpoint + setpoint diff (entered in the user menu)
For inputs higher than 20mA, the water setpoint is set to setpoint + diff.
Remark: The value entered for the setpoint diff can also be negative.
Enable Double
Setpoint
Y
Setpoint
Cooling Double
Heating Double
Setpoint
12.0 ˚C
- - - - ˚C
Setpoint
diff.
Setpoint
Setpoint
Setpoint +
diff.
Input signal
4mA 20mA
ESIE07-05.book Page 54 Friday, December 21, 2007 3:21 PM

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