SOLAR controls WATTrouter ECO User Manual page 38

WATTrouter ECO - user manual
surplus reaches 2 kW the 2
heating coil.
Note: The Prepend function does not affect relay output priorities. For example, if the relay 2 is set to
the nearest lower priority than the relay 1 but has a higher Prepend value than the relay 1, the relay 2
will not be prepended before the relay 1. Therefore, in this case, higher Prepend value for relay 2 than
for relay 1 is not meaningful, so don't set it.

Minimum power – for proportional outputs when PWM function is used then this value gives the
minimum power for the connected load. The output will not be activated unless available surplus
energy exceeds this threshold. Nonzero value can be useful e.g. for proportional control of inverter air
conditioner or heat pump. These devices usually don't run with less than 1/3 of nominal power. For
more information about controlling air conditioners or heat pumps proportionally see manufacturer's
web site.

PWM-I – for proportional outputs when PWM function is used then this value is equal to the I-
component value of the PID-regulator assigned to this output. The value can be selected between 1
and 1000. Select value according to the dynamics of the connected system (battery charger, heat
pump etc.). Start with a small value (1 to 10) and gradually increase the value if the system dynamics is
slow. For values less than 100 the dynamics is rather slow so that the system will enable to switch
outputs with lower priorities, to cover available surplus energy. If the Minimum power field is nonzero
the control will start after 3 minutes. In the meantime minimum power is held – aimed for soft-starts
of air conditioners or heat pumps.
Caution: In case of a too big PWM-I value the system may become unstable and this status may
damage the connected device, when there is no built-in protection in the device!

PWM range – (since firmware version 1.7) these values can be used to limit physical PWM or 0-10V
output to given subrange. Here we suppose a PWM/0-10V converter is used that converts PWM signal
of the output to 0-10V signal. For example, if we need a signal that is 1-10V (1V corresponds to zero
power, 10V corresponds to full power) then we set 10-100%. Similarly if we need a signal that is 2-5V
(2V corresponds to zero power, 5V corresponds to full power) then we set 20-50%. The output within
this range is linear and even for the smallest possible subrange (10% of the full range, so e.g. 10-20%
i.e. 1-2V) is fine enough and has minimum resolution of 100 levels (for smallest subrange of 1V it
means the resolution is 10mV).


On-delay time – this value applies only for relay outputs. This delay time runs from the moment a
condition has been detected to switch the relay output on. By this condition we mean that the
corresponding energy surplus exceeds the limit set by the "Connected power" field, which is further
increased by internal fixed hysteresis of 0.1 kW. After the time elapses the relay is really switched on.
It is recommended to use the default value, or to slightly increase it if the relevant load cannot be
switched on frequently. The value may be decreased down to 2s. However, such small delay time may
sometimes cause false load switching. Therefore, we recommend decreasing the value only in certain
cases and after proper testing. This time delay is not active in CombiWATT and TEST mode.

Switch-off delay - this value applies only for relay or PWM outputs. For relay outputs this delay time
runs from the moment a condition has been detected to switch the relay output off. After the time
elapses the relay is really switched off. This feature is necessary for loads which cannot be switched on
frequently. The value may be reduced down to 2s. For example, for heat pumps we recommend
How to fit and setup the device
nd
heating coil will be connected (prepended) before boiler and 1
www.solarcontrols.cz
st
Page 38 from 66