Grounding A Tec - Newport 6100 User Manual

Tips and Techniques
the drive current, which the limit circuitry may pick up as a hard limit
and shut down the Temperature Controller subsystem.
7.3

Grounding a TEC

The Model 6100 Temperature Controller outputs are isolated from earth
(chassis) ground. Isolating the TEC case avoids damaging the device from
multiple ground loop potentials, AC transients, or static discharge. Since test
equipment probes, signal sources, and package mounts are often partially
earth grounded, it is often necessary to also bond the device case to earth
ground. It is strongly recommended that a single point ground scheme be
established, specifically at the binding post. This will help minimize noise,
transients, and ground loop hazards. Be sure to include any signal generators
in your ground circuit.
If you have additional questions about your earth grounding method, contact
a Newport applications engineer.
7.4 Laser Limits
The Laser Diode Driver subsystem has several limits to protect the laser
diode from damage. The limits include current and compliance voltage.
7.4.1 Current Limit
The current limit is actually two limit circuits:

The first circuit maintains the current limit by not allowing the drive
current to exceed the limit's set point. This form of limiting is called the
soft limit, and does not affect the operation of the laser except to limit the
drive current.
Do not connect the temperature sensor to Earth Ground at the
same time with grounding either TE+ or TE-. Only one
connection to ground is accepted. Failure to do so may result in
the unit malfunction or/and damage. Be careful when
connecting other instruments to 6100 Laser Diode and
Temperature Controller, as they may have their ground
connected to the Earth Ground.
For example, oscilloscopes have the probe ground connected to
Earth Ground. If either TE+ or TE- is already connected to Earth
Ground, the oscilloscope may bring the second connection,
causing malfunction or damage.
CAUTION
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