Section 2 – SR-2 Hardware Description
Programmable Features Display Heater
The settings of all programmable features are held
in non-volatile memory in the microprocessor. The
settings are supplied to the HMI Control Panel each
time the unit is turned on. If the HMI Control Panel
is changed, the current programmable feature
settings will be supplied to the HMI Control Panel
when the unit is turned on.
The HMI control panel is equipped with a display
heater. This heater is needed to make the display
visible in cold ambient temperatures.
The HMI has its own internal temperature sensor for
the display heater. The heater is energized when
the unit is turned on and the ambient temperature is
below 29.4°F (-2°C). The heater turns off when the
temperature sensed by the internal sensor rises
above 37.4°F (+3°C). The heater draws from 1.4 to
1.7 amps when energized.
Fuse F10
When interface board fuse F10 is installed in the
upper position, the On/Off keys on the HMI turn the
unit on and off. When fuse F10 is installed in the
lower position the unit will start and run without the
HMI control panel. Do not operate the unit with the
F10 fuse installed in the lower position unless
absolutely necessary.
The colder the ambient temperature the longer it will
take for the heater to make the display visible on a
cold startup. It may take 10-15 seconds for the
display to appear with very cold temperatures.
2-7
31 January 2005
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