Arroyo Instruments TECSource 5400 Series - Instrument Interfacing and Internal Power Management; Linking Instruments; Internal Power Management

Page 48 · 5400 Series TECSource User’s Manual
and B values are 1.000 and 0.00, respectively, but can be adjusted to change
the sensor measurement. The calibrated measurement is computed as follows:
User calibrated reading = M * reading + B
For set point, such as ITE set and analog output, the set point is calculated as
follows:
User calibrated setpoint = M * set point + B
B is always in the units of the sensor or TEC measurement (for example, kilo-
ohms (kΩ) for thermistors, and ohms (kΩ) for RTDs, Amps for ITE current, etc.).
Linking Instruments
The TECSource has the ability to link to a 4400 LaserSource to provide
extended functionality, including a laser interlock that prevents operation of the
laser without the TEC on and stable. When linked, the green Link LED will light.
Upon the release of the 4400 LaserSource, a firmware update of the
TECSource will be made available to enable this feature.
Internal Power Management
The TECSource is a powerful instrument, capable of delivering nearly 1000W in
some configurations. When driving a low voltage load at higher currents, a
condition can arise where the voltage of the load is too low, and unaddressed,
would result in excessive heat inside the instrument.
To manage this internal thermal load, the TECSource relies on two methods of
power control: a tunable power supply and current limiting. Where possible, the
internal power supply will be adjusted to minimize the thermal load inside the
instrument.
In some cases, power supply adjustments are not enough, and the instrument
will then reduce the drive current until the internal thermal load is within the
maximum allowable load. In many cases, this will have little effect on the
operation of your application, but may slow the transition from one temperature
to another. When operating in this condition, the display will show an HSLimit
indicator on the display.
However, there may be conditions where the reduced current actually prevents
the mount from achieving the desired operating temperature. The only solution
in this case is to increase the load voltage. The simplest method is to wire a
power resistor in series with the TEC to create additional voltage. Depending on