Agilent Technologies 1100 Series Reference Manual page 239

Introduction to the Detector 6
Conversion and subsequent calculation to achieve absorbance values include
the following tasks:
• dark current correction,
• PDA (photo diode array) temperature compensation,
• absorbance calculation, and
• signal averaging.
SIMM Memory Module
The main board versions -66500, -66520 and -66530 provided 4 slots for
extended memory (up to 4 × 1 MB or up to 4 × 4 MB to accommodate more run
buffer (signal and spectral data). Only 1 MB was used (no need to upgrade for
any application). With main board version -66540 the slots were removed and
the 1 MB memory is now on-board (no upgrade possible)
Firmware
For an outline of the firmware, see "Firmware Description" on page 246. In
case you require exact mathematical equations for the transformation, see the
Understanding Your Agilent ChemStation handbook.
Leak Sensor
This block consists of a PTC for the leak detection and a NTC for the ambient
temperature compensation. A leak would cool down the PTC and this change
in resistance would generate a leak signal.
Fan Drive
The operation of the fan is controlled by the main processor and runs with
constant revolution. The fan produces a sense signal which is derived from the
revolution. This sense signal is used for diagnostics.
On-board Battery
An on-board lithium battery buffers the electronic memory when the module
is turned off.
For safety information on lithium batteries see "Lithium Batteries
Information" on page 303.
1100 Series DAD and MWD Reference Manual 239