4. ADVANCED SETTINGS 29
4.2 Control algorithms
P13 OFF min.
medium
max. P10 P11 P12
P13
P13 1
2 Fig. 4.c
P13 OFF
ON P14
1
2 Fig. 4.d
ENGL ISH constructor
P08 P07 P07 P08 OFF
min.
medium max. P09
set point
P09
P09 P09
P09 P09
1 2
3 Fig. 4.f
OFF P32 min.
P33 P32 P33
Fig. 4.e
ENGL ISH constructor
4.2.3 General functions: Flush (fan on/off cycles)
To overcome the phenomenon of air stratifi cation, the e-drofan operates fan on/off cycles at minimum speed, even when the room temperature has reached the set point (the local/hot/cold valve remains closed). This helps ensure the correct measurement of the room temperature if the probe on the acqua terminal is not used (control probe B1). If control is performed by probe BT, the fl ush function is disabled.
The behaviour can be modifi ed depending on the operating mode: heating, cooling, dehumidify or automatic. The fan is started after a period of inactivity (due to the set point having been reached or the heat enable or cool enable functions), equal to the value of parameter P32.
The local/hot/cold valve should be installed to use the fl ush function.
par. def. min. max. unit of measure
setting
P34 0 0 3 0= Function disabled;
1= Flush function active in cooling, dehumidify and automatic OFF.
2= Flush function active in heating and automatic OFF.
3= Flush function active in heating, cooling, dehumidify and automatic OFF.
P32 2 0 255 min 0= Flush disabled
>0: Period of fan inactivity (due to the control or fl ush function)
P33 90 0 255 s 0= Flush disabled
>0: Fan duration
Table 4.g
4.2.4 General functions: Extra Flush
This function ensures correct operation when the acqua terminal is not fi tted (control probe B1), overco- ming the phenomenon of air stratifi cation.
Whenever switching from OFF->ON or changing operating mode, the e-drofan runs a fan cycle at mini- mum speed (for the time P35) to make sure the room temperature is uniform.
At the end of this interval, normal operation resumes. This is especially useful in the event of automatic operation. It is deactivated if probe BT on the terminal is used for the control functions.
The local/hot/cold valve should be installed to use this function.
4.2.5 General functions: Autofan (fan speed selection based on the room temperature)
The Autofan function establishes the fan speed when this is not set manually by the user.
In cooling and heating mode the speed is higher the more the room temperature deviated from the set point (including automatic cooling, automatic heating). In fan mode the speed is fi xed at the medium value for the range set by parameters P30, P31, P06 (see the paragraph below). In dehumidify mode the speed is fi xed at the minimum value.
par. def. min. max. unit of measure
setting
P07 7 0 255 °C/10 Deviation of the room temperature from the set point above which the fan is activated at medium speed
P08 7 0 255 °C/10 Deviation of the room temperature from the set point above which the fan is activated at maximum speed
P09 5 0 255 °C/10 Hysteresis of the room temperature-set point deviation Table 4.h
4.2.6 General functions: Continuous ventilation
If required, the fan can be activated in permanent mode; the fan speed is set by the user even when the room temperature has reached the set point (in AUTOFAN the speed is set to the minimum value). The heat cool enable functions have no effect.
parameter setting
P29 0= Continuous ventilation deactivated.
1= Continuous ventilation activated.
Table 4.i The local/hot/cold valve should be installed to use this function.
Key:
1. heating (winter);
2. cooling (summer) 3. room temperature.
ENGL ISH constructor
4.2.7 General functions: Comfort
This function, if activated by P36, disables the modifi cation of the set point, allowing only an offset of +/- 3°C from the set value (in heat, cool, dry and automatic modes).
On the e-drofan master, the set point can be set via a serial connection (see the corresponding paragraph), while the slaves receive the set point from the related master and apply any offset (set from the terminal).
The master automatically loads the set point saved for parameter p01 when starting; this is subsequently modifi able via a serial connection. Set the logic and dependence parameters suitably.
E.g. In a hydronic system, the set point can be set on the e-drofan master and the slaves only allow mo- difi cations of +/- 3 C.
E.g.. In a centralised system (hotel), the room set point can be set via serial, allowing the guest the possi- bility to change it by +/- 3 C.
4.2.8 General functions: Occupancy
This function is used to set a second set point applied if the environment is not occupied, allowing the air-conditioning system to consume less energy and thus achieve cost savings.
The set point is increased by the value set for parameter P18 in cooling/dry mode, or decreased by the value set for P19 in heating mode.
Three typical situations have been identifi ed, represented by parameter P93 “occupancy type”; each type can be optimised using time bands (set via a supervisory system) and occupancy sensors.
status of the instal- lation
occupancy type room status e-drofan operation event activating control at the set point symbol on master terminal OFF (command sent
only once from supervi- sory system)
0 Unoccupied/
occupied
OFF 1= meeting room
2= corridor 3= offi ce ON+ECO (command
sent only once from supervisory system)
0 Unoccupied/
occupied
set point= economy 1= meeting room Unoccupied set point= economy
+ Occupied set point=set value.
When the occupancy timer has elapsed, e-drofan will return to set point = economy.
The occupancy timer is set as follows:
1. Pressing any button (except the ON/OFF button);
2. Pressing the sleep button or activation of the occupancy digital input.
2= corridor Unoccupied/
occupied
set point= economy
+ 3= offi ce Unoccupied set point= economy
+ Occupied set point= set value.
When the occupancy timer has elapsed, e-drofan will return to set point = economy.
The occupancy timer is set as follows:
1. Pressing any button (except the ON/OFF button) or activation on the occupancy digital input;
2. Occupancy timer reset when pressing the sleep button or activation of the occupancy digital input.
ON (command sent only once from supervi- sory system)
0 Unoccupied/
occupied
ON
1= meeting room Unoccupied set point= economy Occupied set point= set value.
When the occupancy timer has elapsed, e-drofan will return to set point = economy.
The occupancy timer is set as follows:
1. Pressing any button (except the ON/OFF button);
2. Pressing the sleep button or activation of the occupancy digital input.
2= corridor Unoccupied set point= economy Occupied set point= set value.
When the occupancy timer has elapsed, e-drofan will return to set point = economy
The occupancy timer is set upon activation of the occupancy digital input.
3= offi ce Unoccupied/
occupied
set point= set value • No digital input: Set point always = set value. Pressing the sleep button for 5 s. activates the * symbol and the set point= economy.
• With digital input:
1. Pressing any button (except the ON/OFF button) or activation on the occupancy digital input;
2. Occupancy timer reset when pressing the sleep button or activation of the occupancy digital input.
Table 4.j.a
• In all modes the change ON+ECO->ON or OFF->ON sets the “occupancy timer”, that is, on power-up the e-drofan starts with set point equal to the set value.
• In all modes (except corridor), holding the sleep button for 5 seconds the e-drofan takes set point= set value without time limits until receiving the OFF command; the set point may return to economy by pressing the sleep button again or switching the unit OFF or alternatively by disconnecting and recon- necting power to the e-drofan.
In a hydronic network the occupancy function shares the same variables as the economy/sleep functions, meaning the slaves can be forced to follow the status of the master (simply set the function on the ma- ster). In any case, the occupancy on a slave can be managed locally (obviously this must be fi tted with a terminal) by activating the function using the corresponding parameter; in this case the activation request (following the detection of occupancy on the master) is ignored.
100%
1
2 3
4 5
6 6
7
8 8
9 10
Fig. 4.h.b
ENGL ISH constructor
With the remote lock function active (dipswitch 3= ON) pressing the sleep button for 5 seconds does not switch to occupied mode without time limits.
Below is an example of occupancy management in a centralised system for offi ces:
time band installation status description rooms
00.00 06.00
Installation OFF
The installation remains off and ignores the requests from the fan coil All types
06.00 08.00
ON+ECO The installation starts air-conditioning the rooms, preparing them for the arrival of the personnel.
The fan coils start from unoccupied (set point= economy, e.g. 16°C in heating) and if necessary switch to occupied according to the types shown above.
• offi ce
• meeting room 08.00
12.00
Installation ON The installation controls the temperature of the rooms to ensure the comfort of the personnel.
At 8:00 all fan coils are activated at the set point= set value (e.g. 20°C in heating) for a time equal to the occupancy timer;
upon expiry of the timer, the fan coils return to the management depending on the type.
All types 12.00
14.00
ON+ECO The installation returns to unoccupied during the lunch break (set point= economy, e.g. 16°C in heating), maintaining comfort only where required.
• offi ce
• meeting room 14.00
18.00
Installation ON The installation starts air-conditioning the rooms again to ensure the comfort of the personnel (e.g. 20°C in heating). At 14:00 all the fan coils are activated at set point =set value (e.g. 20°C in heating) for a time equal to the occupancy timer; upon expiry of the timer, the fan coils return to the management depending on the type.
All types 18.00
20.00
ON+ECO The installation returns to unoccupied due to the absence of personnel (set point= economy, e.g. 16°C in heating), maintai- ning comfort only where required.
• offi ce
• meeting room 20.00
24.00
Installation OFF The installation remains off and ignores the requests from the fan coil All types
Table 4.j.b
4.2.9 General functions: P+I algorithm (cooling/heating/automatic)
The e-drofan features a P+I algorithm that is used to control modulating valves with 0 to 10 Vdc input and 3 point valves.
Control can be performed on the BT probe on the terminal (room temperature, enabled by dipswitch 6) or on one of the three probes on the e-drofan (e.g. air intake temperature), by setting the corresponding parameter.
The P+I algorithm is activated by enabling one of the modulating valve outputs and setting the proportio- nal band and integral time parameters.
Below is a diagram showing the use of the modulating valves in heating mode.
Key:
1 P+I output 2 control probe (°C) 3 heater activation 4 open valve 5 close valve 6 P109 dead band
7 P112 ON/OFF heater hysteresis 8 P115 valve proportional band 9 P111 heater proportional band 10 set point
The proportional band determines the temperature range within which the actuator moves from closed to maximum opening with control by the proportional term only. The extent of opening depends on the proportional and integral factors; the proportional factor opens the valve further the more temperature is below the set point, while the integral factor increases the opening of the valve if the device takes a long time to reach the set point (with the temperature above the set point the behaviour is symmetrical, that is, the valve is closed).
Low values of the proportional band cause a fast and intense response but cause system instability (swings between opening and closing of the valve); setting low values for the integral factor offers a fast response but, in this case too, the risk of the system becoming instable remains. The integral factor compensates for any misalignments between the theoretical position and the actual position of the valve (this is phenome- non typical of 3 point valves after a large number of operations).
To correctly set the proportional band and the integral time, run some tests on the fan coil system in the environment being air-conditioned, simulating high load and low load conditions and the typical variations in load. One example of the values that can be initially used is: valve proportional band P115= 30 (3°), P114= 30 (3°) and integral time P108= 60 (that is, 600 s).
A parameter is featured that limits the movements of the valve so as to reduce wear and adapt the P+I
ENGL ISH constructor
output can be established before effectively switching the output (parameter P99).
Parameter P109 is the dead band (to the sides of the set point); within this zone the algorithm accepts minimum variations of the control temperature without performing any action, the purpose is to avoid in- stability and limit the number of operations of the actuator in steady operation (the integral factor remains constant, while the proportional factor is equal to 0). In cooling mode, the behaviour is symmetrical.
For the effective use of the actuators, the fan is activated when the P+I output is other than zero, the fan speed can be set manually or determined by the autofan function (in this case, at least the minimum speed is guaranteed).
The position of the valve can be displayed on the Acqua terminal in the place of the set point (see para- meter P37).
If a series of actuators are used with overlapping set points and proportional bands, the activation is performed in sequence, starting from the resource with the lowest cost (e.g. valve) and ending with the resource with the highest cost (e.g. heater).
The “bumpless transfer” parameter is featured that, in response to modifi cations of the P+I algorithm con- trol parameters during the normal operation of the unit, is used to dampen any swings or over-corrections of the system, especially if the algorithm interacts with a series of devices or actuators.
The P+I parameters are shown in the following table (for the settings corresponding to the various types of valves, see the following paragraphs).
par. description def min max UOM
P99 Minimum P+I output variation for valve movement (0 to 10 V and 3 point valve) and heater increase. Expressed as a % of the total P+I output.
5% 0 100 %
P107 Bumpless transfer
0= no management of the transients for a change in actuator, variation in P+I parameters and variation in the set point.
1= gradual activation when changing actuator
2= gradual activation when changing actuator and gradual response to variations in P+I parameters
3= gradual activation when changing actuator, gradual response to variations in P+I parameters and set point
1 0 3
P108 Integral time
0= Integral factor disabled
0 0 255 s *10
P109 Dead band 2 0 255 °C/10
P111 Heater control set point, expressed as an offset from the set point (ON/OFF management with hysteresis)
30 0 255 °C/10
P112 Heater control set point heater hysteresis with ON/OFF management
5 0 255 °C/10
P114 Cold valve proportional band 0=actuator disabled
0 0 255 °C/10
P115 Hot valve proportional band 0=actuator disabled
0 0 255 °C/10
P116 Modulating heater proportional band 0 0 255 °C/10
When the P+I output is other than zero, the heating/cooling request bits (depending on the mode) are set.
The P+I times for the 3 point valves or thermal valves have a resolution of 1 sec. With P+I active, the heat/cool enable functions are ignored. Set an integral time that considers the travel speed of the modulating valve used.
4.2.10 General functions: modulating valve management
The management of modulating valves requires the algorithm P+I to be enabled.
For the correct use of 3 point valves, the time taken by the valve to completely open or close needs to be entered.
par. description def min max UOM
P97 Maximum valve travel time (or 2 windings) 0 0 600 s
Synchronisation
When the e-drofan is shutdown (switched from ON ->OFF), powered up, or when total closing is reque- sted (in this case, the minimum time between two synchronisation cycles is 6 hours), a complete closing cycle is performed to ensure correct alignment between the position determined by the P+I algorithm and the real position, as there may in fact be misalignments due to mechanical wear after a signifi cant number of operations. The synchronisation procedure is only performed on the 3 point valves, while for the valves with 0 to 10 V input, the function is managed by the electronics on the actuator.
The return to normal operating conditions after a synchronisation cycle is managed according to the normal dynamics of the P+I algorithm, given that the extent of the error at the moment of synchronisa- tion cannot be known.
Small deviations between the theoretical and the actual position are automatically compensated for by the integral factor.
Antistick
To prevent the valves from blocking (due to impurities or the entrainment of solid residues in the water circuit), set movements of the valve are performed periodically. These operations are effected only after
P06 OFF
ON
set point 1
2 Fig. 4.g
min. speed ON P14-P13 (cool enable) Set +P07 set point
medium speed
1
2
3
4
5 6 7 8 9 10 11 Fig. 4.h.a
ENGL ISH constructor
par. description def. min max UOM
P100 Maximum valve inactivity time after which the antistick function is activated.
If= 0 the antistick function is disabled
4 0 255 hours
P101 Forced movement due to antistick function. Considered as a % of the maximum travel set
20 0 100 % max
travel
4.2.11 General functions: fan speed limit
In some applications, the fan speed needs to be limited; this is done by setting parameter P117.
par. description def. min max UOM
P117 Speed enabled:
0= all speeds enabled.
1= Only minimum speed (autofan displayed on LCD terminal, not modifi able). The fan stops only when P+I output =0.
0 0 1
Key:
1. status of the valve;
2. room temperature.
Key:
1. room temperature (B1);
2. exchanger temperature;
3. valve status;
4. fan status;
5. change mode by user;
6. extra fl ush cycle;
7. speed selected by autofan;
8. fan started by cool enable;
9. change speed by autofan;
10. valve and fan deactivated due to set point reached;
11. fl ush cycle.
4.2.12 Manual operation: Cooling - (Management of the hot/cold water valve or cold water valve only)
The activation of the hot/cold water or local/cold water valve is based on the set point set by the user (see the following fi gure), while the fan starts according to the cool enable function (at the speed selected by the user or decided by the autofan function).
When the room temperature (the value read by the control probe) reaches the set point, the hot/cold water or local/cold water valve is closed and the fan is stopped.
par. def. min. max. unit of measure setting
P06 5 0 255 °C/10 Thermostat hysteresis
Table 4.k
Below is an example of the sequence for the activation of the loads on the e-drofan; the device is fi tted with a hot/cold water valve and is in cooling mode, with the fan speed established by the autofan function (control probe B1).
P06 OFF
ON
set point 1
2 Fig. 4.g
P13 P46
set point 1
2 3
P06 4
2
Fig. 4.h P13
set point 1
2 5 P06
4
2
min. speed ON P10+P13 P11+P13 P12+P13 Set-P07-P09 set point
medium speed 1
2
3
4
5 6 7 8 9 10 11
Fig. 4.i
ENGL ISH constructor
4.2.13 Manual operation: heating - (management of the hot/cold water valve or cold water valve only)
The activation of the hot/cold water or local/hot water valve is based on the set point set by the user (see the following fi gure), while the fan starts according to the heat enable function (at the speed selected by the user or decided by the autofan function).
When the room temperature (the value read by the control probe) reaches the set point, the local/hot water valve is closed and the fan is stopped.
par. def. min. max. unit of measure setting
P06 5 0 255 °C/10 thermostat hysteresis
Table 4.l.a Key:
1. valve status;
2. room temperature.
A heater can be used (when dip 5= ON) to improve the heating capacity, with a different hysteresis used according to whether the heat enable function is active. To avoid possible overheating, the fan is activated at the same time as the heater, and remains on for a time equal to P48 after it is deactivated. As a further protection, the heater is deactivated if the temperature of the coil exceeds the temperature set for parameter P47.
par def min max unit of measure setting
P13 10 0 255 °C/10 Hysteresis for heater with heat enable active
P46 30 0 255 °C/10 Hysteresis for heater with heat enable not active
P47 40 0 255 °C Maximum exchanger temperature for heater off
P48 20 0 255 s Post-ventilation for heater
Table 4.l.b Key:
1. heater ON;
2. room temperature;
3. heat enable not active (with hot water);
4. valve ON;
5. heat enable active (without hot water).
Below is an example of the sequence for the activation of the loads on the e-drofan in heating mode; the device is fi tted with a hot/cold water or local/hot water valve and is in heating mode, with the fan speed established by the autofan function.
Key:
1. room temperature (B1);
2. exchanger temperature (heat enable);
3. valve status;
4. fan status;
5. change mode by user;
6. extra fl ush cycle;
7. speed selected by autofan;
8. fan started by heat enable and change speed;
9. change speed by autofan;
10. valve and fan deactivated due to set point reached;
11. fl ush cycle.