M A I N T E N A N C E A N D T R O U B L E S H O O T I N G
Troubleshooting
05_11
LDT-5500B Series
43
C H A P T E R
5
Troubleshooting
This section is a guide to troubleshooting the LDT-5500B Series Temperature
Controller. Some of the more common symptoms are listed here, and the
appropriate troubleshooting actions are given. We recommend that the user start
at the beginning of this guide. Read the symptom descriptions, and follow the
steps for the corrective actions which apply. If you encounter problems which are
beyond the scope of this guide, contact your ILX Lightwave representative.
Symptom
Causes and Corrective Actions
LDT-5500B Series unit will not
power up
Check AC power line voltage and power cord connections.
Power on, but display is frozen
and switches don’t work
This may occur if the unit loses power (AC line) briefly. Turn the
power switch off and on again to restart.
Power on, but no TE current
output
If TE OPEN indicator is lit, check the load connections and then
try again. If SENSOR OPEN or TEMP LIMIT indicators are lit,
check the temperature sensor connections and then try again.
Power on, but measured ITE
current is always about 0.0A
Check to ensure that the I LIMIT parameter is not set to 0.0A.
If SENSOR OPEN indicator is lit, check the sensor connections
and then try again.
Check that the back panel SENSOR SWITCH position is set to the
proper sensor type.
Check that the sensor’s temperature calibration constants (C1,
C2, and C3) are correct values for your sensor type.
Power on, but temperature is
not controlled
Check that the GAIN setting is not too low and that the I LIMIT
value is not too low for your thermal load.
Check the adjust ENABLE switch; the indicator must be lit for any
adjustments to be made.
Unable to adjust output or
parameter
Check the MODE or DISPLAY switch; if they do not respond, the
unit may be in measurement calibration mode (see Chapter 3);
press the OUTPUT switch to abort this mode.
Unable to switch DISPLAY,
MODE, SENSOR CAL or
PARAMETER modes
The unit may be in measurement calibration mode (see Chapter
3); press the OUTPUT switch to abort this mode.
Check that the AC power cord connection is secure; power line
drop outs may reset the unit and when the power is restored, the
output will be off.
Output goes off intermittently
Check the TE module connections; a high impedance on the TE
load may cause the output to exceed the compliance voltage
momentarily, thus shutting the output off.
R Mode set point is not saved
The R mode set point value is not independent from the T mode
set point value; if the control mode is changed from R mode to T
mode, the R set value will change to a value which corresponds to
the temperature, based on C1, C2, and C3.