GE Optica - Page 40

Installation 2-19
January 2006
Heat Pump Controller
Settings
The 1311XR’s heat pump controller module has the following
settings:
Note: The third-stage power indicator may blink in any setting. This
is normal.
Fourth-Stage Power
Supply Control Knob
The control knob on the 1311XR’s fourth-stage power supply sets the
power consumption limit and the coolant requirement when
measuring dew/frost points using the AUTO or BELOW –55°C
settings. Set this knob to the lowest anticipated dew/frost point.
If the control is set lower than necessary, the system dissipates excess
power and requires additional cooling to remove the extra heat
generated. If the setting is too high, the system may not be able to
reach the true dew/frost point.
To allow the 1311XR sensor to act as a turnkey system (whereby it
will cover its entire range automatically), set the switch to AUTO and
the power supply control knob to the –80°C position.
Heat Pump Controller
Error Indicators
The heat pump controller module has two overheat indicators
connected to thermal shutdown switches. If either indicator comes on,
check for and correct any problems before continuing operation.
Check the cable connections, coolant flow and coolant temperature.
Table 2-2: Model 1311XR Heat Pump Controller Settings
Setting Function
AUTO
When set to AUTO, the system operates fully automatically, controlling the heat
pump in response to any dew/frost point within its operating range. In AUTO mode,
the controller senses the current supplied by the Optica to the top two stages of the
thermoelectric coolers. The controller switches on the fourth stage power supply, as
required to maintain the mirror temperature at the dew/frost point.
The AUTO setting is recommended for most applications.
Below –55°C
If the frost point is known to be below –55°C, the switch can be set to this position to
provide slightly faster response than the AUTO setting. However, depression is
limited at this setting. If frost points approaching –80°C are to be measured, use the
AUTO setting.
–65°C to –10°C
If the dew/frost point is known to be between –65°C and –10°C, the switch can be
set to this position to reduce overshoot and settling time.
Above –25°C
If the dew/frost point is known to be above –25°C, the switch can be set to this
position to reduce overshoot and settling time.