Wavelength Electronics LFI-3500 Series, User Manual

Page: 31 / 38

31
Error and Status Indicators
Several LED indicators and a beeper are used to determine the status of the
controller.
Status Section
Power LED: This LED lights green whenever the AC Power Switch on the
front panel is depressed and AC power is supplied to the unit.
Temp Limit LED: This LED lights red whenever the load temperature
exceeds the Limit Temperature as set by the Temperature Limit Trimpot (see
page 26). The limit can be configured to trigger on a HIGH or LOW limit via
the configuration switch on the rear panel. The output current is
automatically switched off when a Temp Limit condition occurs. Once the
error is corrected, the Output On Button must be pressed once to clear the
error and again to enable the output.
Open TE LED: This LED lights red whenever the voltage measured across
the thermoelectric module exceeds the compliance voltage of the LFI
controller. This condition can occur if the impedance of the thermoelectric is
too high for the amount of current being sourced through the device or if
there is no thermoelectric connected to the output connector. This condition
does not shut down the output current, and is only used to indicate a
possible output connection problem.
Sensor Error LED: This LED lights red whenever the main sensor voltage is
either greater than 5 V or less than 0.2 V. This condition can occur if the
impedance of the sensor is too high or too low for the sensing circuit, or if the
sensor is accidentally disconnected from the output connector. The output
current is automatically switched off when a Sensor Error condition occurs.
Once the error is corrected, the Output On Button must be pressed once to
clear the error and again to enable the output.
Output Section
On LED: This LED lights green whenever the Output On Button is toggled
on. This LED indicates that the output is now active and current will flow
through the output connector.
Limit LED: This LED lights red whenever the output thermoelectric current
is limited to the adjustment setting on the Limit Current Trimpot (see page
25). The output current will remain in this condition until the current required
to maintain temperature falls below the Limit Current Trimpot setting. This
condition does not switch the output current off.
Beeper: The LFI beeps once whenever the output is turned on or off.