Lochinvar MP2 - Manual (Page 16)

I NPUT S IGNAL
The control can accept either a 0 - 10 V (dc) signal or a 2 -
10 V (dc) signal. The External Input Signal setting must be
set to the proper setting based on the signal that is being
sent to the control.
0 - 10 V (dc) or 0 - 20 mA
When the 0 - 10 V (dc) signal is selected, an input voltage
of 1 V (dc) corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 V (dc) corresponds to a
boiler target temperature of 210°F (99°C). As the voltage
varies between 1 V (dc) and 10 V (dc) the boiler target tem-
perature varies linearly between 50°F (10°C) and 210°F
(99°C). If a voltage below 0.5 V (dc) is received the boiler
target temperature is displayed as " - - - " indicating that
there is no longer a call for heating.
A 0 - 20 mA signal can be converted to a 0 - 10 V (dc) sig-
nal by installing a 500 ohm resistor between the Out + and
Com - terminals (4 and 1).
2 - 10 V (dc) or 4 - 20 mA
When the 2 - 10 V (dc) signal is selected, an input voltage
of 2 V (dc) corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 V (dc) corresponds to a
boiler target temperature of 210°F (99°C). As the voltage
varies between 2 V (dc) and 10 V (dc) the boiler target tem-
perature varies linearly between 50°F (10°C) and 210°F
(99°C). If a voltage below 1.5 V (dc) is received the boiler
target temperature is displayed as " - - - " indicating that
there is no longer a call for heating.
A 4 - 20 mA signal can be converted to a 2 - 10 V (dc) sig-
nal by installing a 500 ohm resistor between the Out + and
Com - terminals (4 and 1).
O FFSET
The Offset setting allows the boiler target temperature to be
fine tuned to the external input signal. The control reads the
external input signal and converts this to a boiler target tem-
perature. The Offset setting is then added to the boiler tar-
get temperature.
E XTERNAL I NPUT S IGNAL C ONVERSION T ABLES
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