User manual

21
ON
1
OFF
A1 A1+A2
2
ENGLISH
µC
2
SE process chiller +030220416 - rel. 1.1 - 27.04.2010
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
1
st
circuit
Antifreeze probe
1
st
circuit
Cond. temp.
probe
Press probe
1
st
circuit
2
nd
evaporator
Antifreeze
probe
2
nd
circuit
Cond. temp.
probe
Press. probe
2
nd
circuit
2= air/water Chiller B1/B2 single circuit
(B1/B5 two circuits)
B2 B3 B4 B6 B7 B8
4= water/water Chiller B1/B2 single circuit
(B1/B5 two circuits)
B2 Not used Not used B6 Not used Not used
11= Cooling-only air-air unit with electric heating
B1 B2 (low outlet
temperature)
B3 B4 Not used B7 B8
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 fi lter
/21: Establishes the coeffi cient used in the digital fi ltering 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 modifi ed,
the µC
2
SE 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
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).
- Antifreeze alarm differential
A02: This represents the differential for the activation of the antifreeze alarm; the alarm condition cannot
be reset until the temperature exceeds the set point + differential (A01+A02 or A14+A02).
- Antifreeze alarm bypass time low room temperature from unit start in heating mode
A03: This represents the delay in the activation of the antifreeze alarm when starting the system.
- Auxiliary heater probe in heating
A06: This determines which probe is used for control the auxiliary heater. The meaning of the parameter
is the following:
A06 = 0 => Control probe see Table 5.a.a
A06 = 1 => Antifreeze probe see Table 5.a.a
Not valid if A10= 2
- Antifreeze alarm set point limit
A07: Establishes the minimum limit for setting the antifreeze alarm set point (A01).
- Heating (electrical heater or hot gas bypass) set point
A08: Represents the threshold below which the heating function is activated.
The set point in heating is compensated according to the following equation:
The heating function could be realized by electrical heater or hot gas bypass valve. The set point in
heating is compensated according to the following equation:
Set_heaters (heating) = A08 + (Compensated set point - Set point set)
A08 could both be absolute value or relative value to set point according to the parameter r43.
Example of antifreeze/outlet limit management
Fig. 5.a.a
Key:
1. freecooling or comp
2. probe B2