Wavelength Electronics LD2TC5 LAB, User Manual

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ADDITIONAL TECHNICAL NOTES
This section includes useful technical information on these
topics:
• Using the Max Laser Voltage Limit
• Use Passive and Active ld Interlocks
• Clipping LD Current Limit
• Independent/Linked Operation
USING THE MAX LASER VOLTAGE
LIMIT
The Maximum Laser Voltage field can be used as a safety
feature, and a compliance voltage indicator. If the voltage
across the laser attempts to breach the set limit, the instrument
will present an error to keep the laser from operating in
compliance voltage limited mode (not being able to achieve
the full requested output current).
USE PASSIVE AND ACTIVE LD
INTERLOCKS
The passive interlock is designed to trigger if Pins 2 and 3 on
the LDD D-SUB are not shorted. Use this interlock with doors
and enclosures that trigger an open circuit when opened.
The active interlock (ACTIVE LOCK BNC) can be used with
another active system component to disable/enable the LD
current output.
CLIPPING LD CURRENT LIMIT
The LDTC LAB utilizes a clipping LD current limit. This means
that at a current level very near the current limit, the instrument
will clamp the output current at the limit, and continue
operating at that level of output current. Output current will not
be disabled if the limit is reached.
INDEPENDENT/LINKED
OPERATION
The LDTC LAB can operate with the LD and TC sides
independent of one another, or tied. If tied operation is
chosen, the user can choose which TC errors will trigger a
LD output current disable using the Laser Enable Output Off
register (use remote command LASer:ENABle:OUTOFF ).
This register is defined below, in
Table 7 .
DECIMAL HEXADECIMAL TC CONDITION
1 0x0001 Output disabled
2 0x0002 TEC short
4 0x0004 TEC open
8 0x0008 Temperature not stable
16 0x0010 Sensor short
32 0x0020 Sensor open
64 0x0040 Over-temperature
128 0x0080 Under-temperature
Table 7.
Laser Enable Output Off register definitions
Each bit can be individually set. For example, if laser
current needs to be shut down if there is a disconnection
of the temperature sensor or if the temperature exceeds
the maximum temperature limit, the set value would be 96
(sum of 32 for a sensor open condition and 64 for an over-
temperature condition). Sending the remote command
LAS:ENAB:OUTOFF 96
specifies this shutdown condition.
By default, this register is set to zero, configuring for
independent operation.
For more information, see the LAB Series Instrument
Command Set document.