Riello TAU Unit 100, Руководство по установке и обслуживанию

Страница: 24 / 140

24
INSTALLATION
2.12 Modulating circulation pump connection
The regulator on the control panel can manage one modulating
circulation pump (as an alternative to standard 230Vac circula-
tion pumps).
13
12
11
10
9
8
7
6
5
4
3
2
1
14
15
16
PC
PI
MO2
L - PC/PS/PI
0 - 10V
PWM
GND
0 - 10V
PWM
GND
⏚
⏚
N
L - DHW (N.O.) / PB / PI
N
M02 High-voltage terminal board
PI Central heating system pump
PC Thermal unit circulation pump
2.13 PWM control signals
The circulation pump must be controlled via a PWM (pulse width
modulation) low-voltage digital signal. The speed of the circula-
tion pump changes according to the input signal (see par. PWM
input signal.
Here below are the main characteristics required of the PWM
signal.
9
Check the characteristics of your pump PWM signal to ensure
they comply with the features below. Different signals could
irreversibly damage the pump on-board electronics.
PWM low-voltage digital signal
The PWM square wave signal was designed for a frequency in-
terval between 100 and 4000 Hz. The PWM signal is used to set
circulator speed.
Example of Duty cycle
T
U
iH
U
iL
t
T Period of time
t Active duration of the pulse
d Duty cycle
UiH High voltage level of the input signal
UiL Low voltage level of the input signal
IiL Input signal current
Example Evaluation
T = 2 ms (500 Hz) UiH = 4-24 V
t = 0,6 ms UiL
≤
1 V
d % = 100 x 0.6 / 2 = 30 %
IiH
≤
10 mA (depending on
UiH)
PWM input signal
With high PWM signal percentages (Duty Cycles) a hysteresis
prevents the circulation pump activation if the input signal is
around the status switching value.
With low PWM signal percentages, the circulation pump speed is
high for safety reasons.
If when checking the circulation pump the thermal unit does
not receive any input signal - due for example to the breakage
of the signal cable - the circulation pump will carry on working
at maximum speed to dissipate in the shortest time possible the
heat accumulated by the thermal unit.
Speed (%)
0 5 10
100
20 30 40 50 60 70 80 90 100
PWM input signal (%)
Set parameter 135 = 1
PWM signal (%) Circulation pump status
≤
10 Maximum speed
> 10 /
≤
84
Variable speed (from min to
max)
> 84 /
≤
91 Minimum speed
> 91/95 Hysteresis range: on/off
> 95 /
≤
100 Standby: off
9
Verify that the control logic of your pump is directly propor-
tional (as indicated in the chart) and not inversely propor-
tional.