Learning —
Upon reception of an 'ON' signal, the module starts a learning cycle to determine start and
stop temperatures if they are unknown.
The learning cycle may occur for two different reasons:
• The module is starting Legacy mode for the first time and has no idea what the start and stop tem-
peratures are.
• The module received an ON or OFF signal at a temperature that deviates by more than 5.0C from
the previous temperature. This indicates that the currently stored Start and Stop temperatures are
not properly synchronized with the unit driving the input, they are thus cleared and a new 'Learning'
cycle is triggered.
Modulating —
Upon reception of an 'ON' signal, the module modulates between the start and stop tem-
peratures if they are known.
In a similar fashion to the standalone operation mode, the module will run a variable heat algorithm to
modulate the Heat output and attempt to cruise around the control temperature (defined as the midway
point between the 'Start Temperature' and 'Stop Temperature'.
Once the exit criteria of modulation is reached (reception of an OFF signal, max runtime reached, stop
temperature reached), the module starts seeking an 'OFF' signal.
Seeking the off signal —
This state is very similar to the 'Learning' state. The temperature is increased
at a constant rate until the reception of an OFF signal. Once an OFF signal is received, the temperature is
recorded as the now 'Stop Temperature'. If however, an OFF signal is never received and the temperature
reaches 5.0C above the currently recorded 'Stop Temperature', the control temperatures are cleared and
a new 'Learning' cycle is triggered.
In this mode, the temperature is continuously monitored such that if the temperature drops below the 'Fail-
safe Temperature Setpoint' parameter (defined by the last temperature at which the input was enabled
minus the 'Failsafe Offset' defined in the UI of the top module), the base module assumes that the propor-
tional controller driving the input is malfunctioning and automatically falls back in an autonomous Failsafe
mode.
Failsafe
The failsafe can’t be manually selected. Instead, it is automatically entered when the temperature drops
below a specific temperature setpoint. As this can only happen when the VariFlame's inputs are driven by
another entity, the Standalone mode, which functions autonomously, cannot enter in the Failsafe mode.
In this mode, the VariFlame controller will operate in an attempt to keep a relatively constant temperature
while whatever equipment that was driving the previous state the module was is being repaired. Variable
Input (0-10V), Variable Input (4-20 mA) and Legacy operation modes may fall into Failsafe mode at any
time if the temperature read from the attached probe falls at or below the Failsafe Temperature Setpoint.
This value can be derived from the temperature at which the previous mode's input was enabled minus
the Failsafe Offset (defined in the VariFlame). The control will use the temperature read when the
attached input was last enabled (also equals to 'Failsafe Temperature Setpoint' + 'Failsafe Offset') as a
setpoint and parameters 'Start temperature offset' and Stop temperature offset defined in the user inter-
face settings to drive the controller. The notion of Maximum run time is foregone in this mode.
There are 3 ways to exit Failsafe mode:
Pneg-2092
VariFlame Heater with Edge Connect
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