6300 Series ComboSource User’s Manual · Page 41
Working With AD590s and LM335s
Unlike thermistors and RTDs, an AD590 or LM335 is considered an “IC” sensor
because it has an active transistor element that responds to changes in
temperature by producing a current (AD590) or voltage (LM335).
Also unlike thermistors and RTDs, these IC sensors produce a linear response,
making conversion to temperature a very straightforward calculation.
AD590 sensors produce 1μA/K, so that 0°C (which is equal to 273.15K) would
produce 273.15 μA.
Similarly, LM335 sensors produce 10mV/K, so that 0°C would produce 2.7315V.
For both sensors, because the response is linear, the sensor coefficients default
to a slope of 1 and an offset of zero, but can be adjusted to achieve higher
accuracy.
The temperature correction formula for the AD590 or LM335 is:
T = MT
C
+ B
Where T
C
is the temperature (in °C) calculated using the standard conversion
value of 1°C/μA or 0.1°C/mV, as appropriate, and adjusted from Kelvin to
Celsius.
External Fan Control
The ComboSource has a built-in user adjustable 4-12V DC power supply
designed to provide up to 350mA to an external fan, such as those built into the
240 Series LaserMounts. When using the ComboSource with mounts that
require a fan, no additional external power supply is needed, however, the cable
must include the wiring needed for the fan. The 1260B, 1261B, 1262, and 1263
cables include the wiring.
Fan control is setup in the menu using the Ext Fan, Ext Fan Pwr, Ext Fan
Mode, and Ext Fan Off settings.
Ext Fan can be set to Off, Slow, Medium, Fast, or Custom. When set to Off, the
fan power is never turned on. Slow, Medium, and Fast correspond to 9V, 10.5V,
and 12V. To select a different voltage, choose the Custom setting and then
adjust the Ext Fan Pwr menu item to the desired voltage, from 4.0V to 12.0V.
The fan on/off mode can be controlled using the Ext Fan Mode setting. There
are five modes:
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