Cooler Program - Hach BioTector B7000i User Manual

8.3.11

Cooler Program

COOLER
BACKUP PWM
16.0C DIFF
30%
 COOLER 16.0C DIFF, defines the programmed cooler
temperature setpoint (16°C by default) and the operation mode
DIFF (DIFFERENTIAL temperature mode by default). Other
available operation modes are F (FIXED temperature mode) and
B (BACKUP mode).
 In DIFFERENTIAL temperature mode, the cooler's setpoint is
the ambient temperature, which is BioTector temperature, minus
the programmed setpoint. For instance, if BioTector temperature
is 20°C, the cooler setpoint temperature with above default
settings would be 4°C.
 In FIXED temperature mode, the cooler's setpoint can be
programmed at a fixed temperature, e.g. 5°C.
 The BACKUP mode, which can also be programmed manually,
is automatically activated by the BioTector when a cooler fault
occurs. A "54_COOLER LOW TEMP" warning is logged in the
Fault Archive if the cooler temperature has been below 2°C for
more than 600 seconds. If the cooler temperature has been 5°C
greater than the cooler setpoint temperature and <8°C below the
ambient temperature for more than 600 seconds a
"55_COOLER HIGH TEMP" warning is logged.
 Note that the BACKUP mode is automatically cancelled when
the fault is acknowledged in Fault Archive menu.
 BACKUP PULSE WIDTH MODULATION (30% by default)
specifies the cooler control routine, which uses a PWM period of
800 milliseconds to achieve the programmed cooler temperature
for all cooler operation modes. For instance, with the default
30% setting, the cooler is switched on for 240 milliseconds, and
switched off for 560 milliseconds.
 When a cooler fault occurs, the cooler operates in BACKUP
mode, where the cooler is controlled by the fixed PWM
operation. In the BACKUP mode operation, the COOLER
settings above and the temperature sensor information is
ignored.
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