5 – 6
Error Messages
5.2.4
Temperature faults
@//ABB@
##%
This message indicates a faulty result from the sensor measurement.
The sensor type may be wrong, or the model parameters may be
incorrect, or the circuit may be open or shorted.
T
;1P#
This message indicates the derived value of temperature (from re-
sistance) is outside the range
−
150
◦
C to
+
250
◦
C. Verify the sensor
model parameters.
5.2.5
Thermal runaway
@//ABB@
;3%?T
Thermal runaway occurs when the TEC current is positive (attempt-
ing to cool the stage), but the measured temperature persistently
increases. See section 2.2.6 for a more detailed discussion of thermal
runaway.
5.2.6
Polarity change locked out
Turn off TEC to
change polarity
The TEC wiring polarity can be changed using the
TPOL
command
(page 4 – 39 ). However, changes to the TEC polarity can only be
made when the TEC is o
ff
. Turn o
ff
the TEC with the [TEC On
/
O
ff
]
button before attempting to change the TEC wiring polarity.
5.3
Other messages
5.3.1
Restart
QE/#
#
If the AC power supply encounters a brief interruption in line cur-
rent (even as short as 1
/
2 cycle of the AC line), then fast protection
circuits initiate a shutdown of the laser driver, and the entire instru-
ment, to assure protection of the laser diode itself. If AC line power
resumes before the power supply completely shuts down, however,
the LDC500 detects that a power anomaly occured and displays the
LDC500 Series Laser Diode Controllers
