Teledyne M5000B operating instructions Power, Detectorcompartment

4 Operations/Analysis Unit

4.4.3Power

See Figure 4-3. The power to the analyzer unit, enables the switching functions,andtemperaturecontrolforthedetectorcompartment.

Withthemicroprocessorcontrolunit,thefollowinginformationisprovided.

Figure 2-3. Power Module - Block Diagram

The temperature in the detector compartment is controlled by inputs from a RTD device which feeds to a PID controller capable of set points of temperature versustemperaturereadout.

4.4.4Detectorcompartment

After energy has passed through the sample, it arrives at the filter wheel whereitisfedalternatelythroughtwofilters(measuringandreference)before reachingthedetector.

These filters are specially selected for each application according to the absorption characteristics of the compounds under analysis. The reference and measuring filter waveforms occur along a baseline at approximately 16 milliseconds intervals; each reference or measuring waveform reoccurs at a time interval of 33 mS, or one per revolution of the filter wheel.

At the detector, infrared energy is transformed into electrical pulses and fed through an impedance-matched preamplifier (see dwg. A-14619). De- pending upon the application, length of the cell spacer, etc., the gain of the preamplifier may vary from 1 to 10, depending upon the energy intensity at the detector, to achieve an AC signal output of approximately 0.1 to 1.0 volt peak-to-peak.

Additionally,thedetector,filters,andpreamplifierarehousedinanelectri- callyandthermallyisolatedcompartmenttoprovidemaximumstabilityand minimumnoise.Thisbox,orcompartment,isnormallytemperaturecontrolledat 46 °C.

As noted previously, the filter wheel is driven by a synchronous AC chop- per motor which operates at 1800 RPM. The filter wheel performs two func- tions:(1)switchingfilters,and(2)choppingtheopticalsignaltogivepulses whichcanbeamplifiedforhighqualityprocessing.

4–22 TeledyneAnalyticalInstruments

A Business Unit of Teledyne Electronic Technologies