Operating Parameters; Excess Temperature Setpoint; Hysteresis; Excess Temperature Controller Operation - Thermo Scientific BF51841C Operation Manual

Excess Temperature Option("B" Model)

Operating Parameters

Operating Parameters

1. Excess Temperature Setpoint

The Excess Temperature setpoint is typically set about 10 °C (18 °F) above the
operating temperature of the chamber, or to the maximum temperature the
product or process could tolerate.
The Excess Temperature setpoint is selected by holding the SET/ENT button
for three seconds to show "SP" in the top display and the current setpoint in the
bottom display. Adjust the setpoint with the arrow button and press the
SET/ENT to register the new setpoint.

2. Hysteresis

Set the hysteresis ("HYS") of the Excess Temperature Controller to effectively
use the Duration Timer feature.This value is usually 80% of the temperature
difference between the Excess Temperature setpoint and the chamber
operating temperature.
For example, with an Excess Temperature setpoint of 1220 °C and chamber
operating temperature of 1180 °C, set the hysteresis to 32 °C.
The hysteresis also controls the indicator is extinguished and the Excess
Temperature Controller can be reset.
Exit the Operating Parameters by holding the SET/ENT button for three
seconds.

Excess Temperature Controller Operation

After the Excess temperature Setpoint and Hysteresis values are selected, the
controller is ready for operation.The setpoint and hysteresis should be reviewed
and adjusted if necessary, when the main controller setpoint is changed.
During an excess temperature incident, the "EXCEEDED" and "OUT" indicators
are lit on the controller display area when the setpoint is tripped. The
"EXCEEDED" indicator will stay on while the temperature cools to the hysteresis
amount, then turn off.
When the "EXCEEDED" indicator is extinguished, the Excess Temperature
Controller can be reset holding the "up arrow/reset" button for one second when
the normal operating display is showing the current measured temperature and
the setpoint or just the setpoint.
The Exceeded Temperature Duration Timer and the peak Exceeded Temperature
can be viewed either before or after the controller is reset. These are viewed on
the controller display when the SET/ENT button is pressed and released, with the
"tIn" or "HI" in the top display. These values will be erased from the display and
memory when the "up arrow/reset" button is pressed during their respective
display (add the "EXCEEDED" indicator is off).
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