Set
D
ON
OFF
Set + Diff
Set - Diff
R
ON
OFF
Set
English
WIRING
• Carefully follow all the information in the Safety instructions and Wiring diagrams
sections.
GLOSSARY
Set-point
• The set-point is the reference value where the device cuts in to keep the parameter
controlled at the desired value.
Differential (or hystheresis)
• The differential is the maximum allowable parameter deviation from the set-point
before the device cuts in.
It is usually set in a way as to avoid rapid changes around the set-point which could
cause the device, or the equipment it is connected to, to turn on and off frequently.
Direct action
• When a regulator restricts parameter
increase, it operates in a
direct
way.
As in a refrigerating system for example:
as temperature increases, the heat
extraction rate produced also increases
in order to lower the temperature
“Reverse” action
• When a regulator tends to restrict
parameter decrease, it operates in
reverse
.
For example a decrease in temperature
in a heating system corresponds to an
increase of heat production.
Neutral zone or Dead band
• Indicates an interval of values spanning
above and below the set-point, in which
the parameter regulated can change
without having to activate any output.
It is usually used in devices which, due to substantial system inertia, the set-
point can be exceeded even after the equipment is switched off, or to avoid the
overlapping of heating and cooling actions.
Reverse Mode
Temperature
Direct Mode
Temperature
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User Manual – Thermoregulator FHT
