Operation modes
Variable input (0-10V or 4-20mA) mode
In one of these modes, the VariFlame controller receives a 0-10V or 4-20mA signal from an external pro-
portional controller indicating the opening percentage of the output valve. The input is linearly remapped
to a percentage which is then sent to the valve. For example, 0V = 0%, 5V = 50%, 10V = 100%. The acti-
vation of the output is controlled via the Activation Threshold parameter (modifiable through the user inter-
face). If the input voltage supplied is under the activation threshold, the output is disabled. In this mode,
the temperature is also continuously monitored such that if the temperature drops at or below the Failsafe
Temperature Setpoint parameter (defined via the user interface), the VariFlame controller assumes that
the proportional controller driving the input is malfunctioning and automatically falls back in an autono-
mous Failsafe mode.
You must set the following parameters when you select the Variable Input (0-10V or 4-20mA) mode:
Failsafe offset —
Offset applied to the temperature at which the supplied input voltage provided is above
the defined activation threshold. The resulting temperature is used as a temperature setpoint at which the
controller switches to a Failsafe mode.
Failsafe curve adjust —
The value by which the failsafe start temperature diminishes everyday. (This
value is divided by 7 since it is defined for one complete week.)
Failsafe recovery —
Defines how long the VariFlame should operate in failsafe mode before looking for
a signal coming from the main controller. The period starts as soon as the failsafe mode is entered. At the
end of the recovery period, VariFlame will stop and wait for a signal from the main controller. If no signal is
received before reaching the failsafe start temperature, another period will occur.
Standalone mode
In this mode, the VariFlame controller operates independently of any external proportional controller. This
mode uses the setpoint parameter as well as the start and stop temperature offsets from this setpoint (all
modifiable through the user interface) to control a PI loop having for goal to keep the temperature read by
the probes between the start and stop temperatures, using as little fuel as possible.
You must set the following parameters when you select the stand alone operation mode:
Start Temperature —
The temperature at which the VariFlame starts.
Stop Temperature —
The temperature at which the VariFlame stops.
Maximum Runtime —
It is defined as a duration in minutes, for which the heater may run continuously
without reaching the stop temperature; if the loop reaches the Maximum Runtime before reaching the
Stop Temperature, it shuts down regardless of the current temperature.
Legacy mode
In this mode, the base module only receives ON and OFF signals from an external proportional controller.
Temperature curves are stored on a separate module that decides when to ask for heat and when to stop
asking. Based on the reception of those signals, the operation mode can learn what the temperature set-
point is and remain on it for a given amount of time.
In order to achieve this behavior, the Legacy operation mode is separated into multiple states:
Idle —
Default state, operation mode is waiting for an 'ON' signal to be triggered while driving the output
at 0%. If a 'Learning' cycle is unnecessary, the module records the current temperature as the Start tem-
perature and updates it's value.
26
Pneg-2092
VariFlame Heater with Edge Connect
