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5. DESCRIPTION OF THE PARAMETERS
To modify the parameters, see chapter 4 “Parameters.”
• Probe settings: parameters (/*) (see Table 4.a)
- Type of probe: from /01 to /08: enables the reading of the corresponding analogue input or
sets the function
• Functions of the probes
Type of unit Parameter H01
Temp. control
probe
1st circuit
Antifreeze probe Cond. temp. Press probe
1st circuit
probe
1st circuit
2nd evaporator
Antifreeze
probe
2nd circuit
Cond. temp.
probe
Press. probe
2nd circuit
B2 (low outlet
temperature)
B2 (low outlet
temperature)
B2
B3
B4
Not used
B7
B8
B3
B4
Not used
B7
B8
B3
B4
B6
B7
B8
B2
B3
B4
B6
B7
B8
B2
Not used
Not used
B6
Not used
Not used
B2
B3
B4
B6
B7
B8
B3
B3
B4
B7
B7
B8
B2
Not used
B4
B6
Not used
B8
B2
B3
B2 (low outlet
temperature)
Not used
B3
B3
B3
B3
B3
B4
B4
B4
B4
B4
B4
B6
B7
Not used
Not used
B7
B7
B7
B7
B7
B8
B8
B8
B8
B8
B8
0=
air/air
B1
1=
air/air heat pump (cooling/heating)
B1
2=
air/water Chiller
B1/B2 single
circuit (B1/B5 two
circuits)
3= air/water heat pump (cooling/heating)
B1/B2 single
circuit (B1/B5 two
circuits)
4= water/water Chiller
B1/B2 single
circuit (B1/B5 two
circuits)
5= water/water heat pump rev. on gas cooling B1/B2 single
circuit (B1/B5 two
circuits)
heating
B1/B2 single
circuit (B1/B5 two
circuits)
6= water/water heat pump rev. on H2O cooling B1/B2 single
circuit (B1/B5 two
circuits)
heating
B3
7= Air-cooled condensing unit
8= Air-cooled condensing unit rev. on gas
9= Water-cooled condensing unit
10= Water-cooled condensing unit rev. on gas
11= Cooling-only air-air unit with electric
B1
heating
Table 5.a
- Min/max voltage and pressure values
From /09 to /12: sets the minimum/maximum voltage and pressure for the ratiometric signal.
- Probe calibration
From /13 to /20: calibrates the corresponding sensor (from B1 to B8).
- Digital filter
/21: Establishes the coefficient used in the digital filtering of the value measured. High values
for this parameter will eliminate any continuous disturbance at the analogue inputs (however
decrease the promptness of measurement). The recommended value is 4 (default).
- Input limit
/22: Establishes the maximum variation that can be measured by the probes in one unit
program cycle; in practice, the maximum variations allowed in the measurement are between 0.
1 and 1.5 units (bars, °C or °F, depending on the probe and the unit of measure) approximately
every one second. Low values for this parameter will limit the effect of impulsive disturbance.
Recommended value 8 (default).
- Unit of measure
/23: Selects the unit of measure as degrees centigrade or Fahrenheit. When the parameter is
modified, the μC2SE automatically converts the values read by the NTC temperature probes B1,
B2, B3 into the new unit of measure; while all the other parameters set (set point, differential etc. )
remain unchanged.
• Antifreeze, auxiliary heater: parameters (A*)
- Antifreeze alarm set point/outlet limit (low ambient temp. for air/air units)
A01: when probe B2 is installed on the coil represents the temperature (antifreeze set point) of
the water at the evaporator outlet below which an antifreeze alarm is activated; in this condition
the compressors corresponding to the circuit in question are stopped, while the pump remains
on to decrease the possibility of freezing. The alarm is reset manually (or automatically, depending
on parameter P05) only when the water temperature returns within the operating limits (that is,
above A01+A02).
In the Air/Air units (H1=0,1) the value represents the low room temperature warning threshold;
this alarm, activated according to value read by probe B1 or B2 (depending on parameter A06) is
signal only, and is reset depending on the value of P05.
If probe B2 is placed in the outlet air flow (air/air units), A01 becomes the outlet limit, and if the
outlet probe reading (B2) < outlet limit (A1) then:
1. bypass waiting time A3;
2. stop the compressors; if already off go to pt. 4;
3. bypass waiting time A3;
4. close damper with 50% duty cycle if FC active and the ambient temperature means damper open
or dead zone. If FC is not active go to pt. 6;
5. bypass waiting time A3 after having closed r28 twice (from the end of the last period);
6. If B2 < A1 the alarm “A1” is activated. The alarm reset depends on P5.
34
Example of antifreeze/outlet limit management
1
ON
OFF
A1
A1+A2
2
Fig. 5.a.a
Key:
1. freecooling or comp
2
2. probe B2
μC SE - +030220426 - rel. 2.3 - 10.06.2011