Controlling Loads - Emerson XM670K Installing And Operating Instructions

12 Controlling Loads

12.1. Temperature Probe
Reference for Regulation
Up to 5 temperature probe can be used for the
temperature regulation. It is possible to set the probes used
for temperature regulation. Up to 5 Temperature inputs Pb1,
Pb2, Pb3, Pb4, Pb6, can be used.
To support above function, the parameters rPA, rPb, rP3, rP4,
rP5 are used. Which temperature probe methods of combine
is set by par. rPd among the following: Average, Minimum,
Maximum, First, or Mix.
rPd = rPA: Temperature detected by the probe set in the
parameter rPA.
rPd = rAb: Mix between rPA and rPb defined by rPE parameter.
rPd = AUr: Average temperature of all the probes defined as
Regulation Probe in the parameters rPA, rPb, rP3, rP4.
rPd = LoE: Minimum value among all the temperature probes
defined as Regulation Probe in the parameters rPA, rPb, rP3,
rP4.
rPd = HiE: Maximum value among all the temperature probes
defined as Regulation Probe in the parameters rPA, rPb, rP3,
rP4.
12.1.1. Sensor Failure
In case of multiple temperature sensor regulation: (rPd = rAb,
Aur, LoE, HiE), and with sensor failure, the remaining sensors
are used for the regulation.
In case of all sensor failure, the regulation will be performed
according to Con and COF parameters.
12.2. Dual Temp Mode Operation
Controller can have up to 4 pre-set regulation.
The preset regulation is set in the parameter MAP.
By digital input or supervising system is possible to enable the
second regulation mode, set in the parameter M2P.
In this way a dual temp case can be easily set and controlled.
12.2.1. Second Map Function by Digital
Input Configuration
By setting on digital input among i1F, i2F, i3F as the "nt" the
map set in the parameter MP1 is loaded when the digital input
is enabled.
12.3. The Solenoid Valve
The regulation is performed according to the temperature
measured by the thermostat probe that can be physical probe
or virtual probe obtained by a weighted average between two
probes (see parameters table description) with a positive
differential from the setpoint. If the temperature increases
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and reaches setpoint plus differential the solenoid valve is
opened and then it is closed when the temperature reaches
the setpoint value again.
In case of fault in the thermostat probe the opening and
closing time of solenoid valve is configured by "Con" and
"CoF" parameters.
12.4. Pump Down Before Defrost
The following parameters has been added:
Pdt pump down type (nu; FAn; F-C)
With Pdt = nu, the pump down is not enabled.
With Pdt = Fan, when a defrost trigger is given:
a. Compressor relay will be open.
b. EEV valve (if present):
i. will be closed with CrE = N, Y
ii. will be open with CrE = EUP or EU5
c. Fan will be forced on for Pdn time
With Pdt = F-C, when a defrost trigger is given:
a. EEV valve (if present):
i. will be closed with CrE = N, Y
ii. will be open with CrE = EUP or EU5
b. Compressor relay and Fan will be forced on for Pdn
time
Pdn pump down duration (0 to 255 minutes)
12.5. Defrost
12.5.1. Defrost Starting
In any case, the device checks the temperature that is read
by the configured defrost probe before starting the
defrost, after that:
• (If RTC is present) Two defrost modes are available
through the tdF parameter: defrost with electrical
heater and hot gas defrost. The defrost interval is
controlled by the parameter EdF: (EdF = rtC) defrost is
made in real time depending on the hours set in the
parameters Ld1 to Ld6 in workdays and in Sd1 to Sd6
on holidays; (EdF = in) the defrost is made every IdF
time.
• Defrost cycle starting can be operated locally (manual
activation by means of the keyboard or digital input or
end of interval time) or the command can come from
the master defrost unit of the LAN. In this case, the
controller will operate the defrost cycle following the
parameters it has programmed. At the end of the drip
time, it will wait until all the other controllers of the LAN
finish their defrost cycle before restarting the normal
regulation of the temperature according to dEM
parameter.
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