Tec Grounding Considerations - ILX Lightwave LDT-5900 Series User Manual

When the LDT-5900 is controlling a thermoelectric (TE) module in cooling
mode, current flows from TEC+ (pins 9, 10, 21 and 22 connected internally) to
TEC- pins (12, 13, 24 and 25 connected internally). This is referred to as
positive current. Sensor current (10 A, 100 A or 1 mA) flows through the
sensor connected at RT+ (pin 15) and RT- (pin 14). A voltage develops across
the temperature sensor connected to these pins and can be accurately
measured at the sensor through the 4-wire voltage sense pins (1 and 2), RT+
Sense and RT-Sense. Similarly, the TE voltage can be accurately measured
through the 4-wire TE voltage sense pins 7 and 8. The sensor input (pins 14
and 15), as well as the RT sense and TEC sense (pins 1,2,7, and 8) should be
floating with respect to ground. Pin 6 is connected to the chassis, which is
connected to earth ground via the AC power cord earth conductor.
ILX recommends using either the CC-591H, 5900 TE Controller / unterminated
10A interconnect cable or the CC5955 TE Controller / Laser Diode Mount 5A
interconnect cable to connect the module to the load. The CC-59X Series cables
are specifically designed to be compatible with the 5900 Series Temperature
Controllers. See the ILX Lightwave product catalogue or contact ILX Customer
Service (see page xii for contact information) for information about the cable.

TEC Grounding Considerations

The cable ID ground (pins 4 and 5) are isolated from chassis ground (pin 6). The
chassis is provided for shielding purposes only.
Do NOT connect the TEC Module pins (9, 10, 12, 13, 21, 22, 24 and 25) to any grounded
pins (4, 5 and 6) or damage could occur to the module.
01_10
Note: If you choose to assemble your own interconnect cables, 18AWG wire is
recommended to minimize voltage drop at high current. Note that the DB-25 connector pins
are rated for I = 2.5A, and thus all four TEC+ pins (9, 10, 21, 22) must be used if 10A
nominal
is to be delivered to a load as well as all 4 TEC- pins (12, 13, 24, 25) for the return.
Also, the cable ID pins must be configured as follows or the output current from the
LDT-5900 will be limited to 1A.
MAX Output Current
10A
5A
Cable ID1 Cable ID2
Pin 17 to 4 Pin 18 to 5
Shorted Shorted
Shorted Open
O P E R A T I O N S
Genera l Opera t ion
LDT-5980/ 5948
2
C H A P T E R
13