Brookfield Temperature Controller, Model 75 - Manual (Page 9)

Brookfield Engineering Labs., Inc. Page 9 Manual No. M/98-205-A0100
Note: The last scrolled-to-temperature (the last setpoint temperature) will be retained in
non-volatile memory and will become the default setpoint temperature the next time
the temperature controller is powered up.
6) Temperature control of the Thermo Container will be maintained for as long as the Model
75 Controller is powered up, or until the
RUN
STBY
key is pressed to stop the control action.
VI. ERROR MESSAGES AND FAIL SAFES
If the display shows an error message or there is a continuous “beeping”, you are in one of
the following error conditions:
1) The RTD probe has become disconnected from the Model 75 Controller. Plug the RTD probe
in to correct the error.
2) The Model 75 Controller is providing power to the Thermo Container, but the temperature
sensor is not reporting an increase in temperature. The power to the Thermo Container will be
interrupted. It will be necessary to power down the Model 75 Controller and determine the
cause of the fault before continuing operation.
3) The Model 75 Controller sensed a temperature higher or lower than its built-in limits. The
following paragraphs provide further detail.
VI.1 Open Sensor Error
If the sensor fails or an open circuit condition occurs (infinite resistance), the unit will cause a
probe error as follows:
0 Л В ‰
Note that this error message could be momentarily preceded by either of the following displays:
l Ï - -
h 1 - -
The Model 75 Controller will stop control and will stay in this state until the problem is corrected.
This is usually due to the RTD temperature probe not being plugged into the Model 75 Controller.
Once corrected, the unit will return to viewing the “controlled” temperature.