Teledyne 300M - Manual (Page 87)

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A
9 ADJUSTMENTS
NOTE
The operations outlined in this chapter are to be
performed by qualified maintenance personnel only.
All adjustments to the Model 300M are easy to make. Pots and test points are readily accessible
without removing any components. Figure 1-2 is a plan view of the Model 300M CO analyzer
showing all the major components. Figure 9-1 is an electrical block diagram of Model 300M CO
Analyzer.
9.1 Power Supply Board Adjustment
The power supply board provides ±15 v, +12 v, and +5 v DC power to the analyzer. Also four
temperature linearization circuits for the bench temperature, sample temperature, box
temperature, and the gas wheel temperature are located on the power supply board.
Each circuit is a Whetstone bridge with the measuring thermistor being one leg. A feedback
circuit performs the required linearization. Zero adjust pots have been factory set and no field
adjustment should be required.
9.1.1 Box Temperature Limits
The box temperature is measured by a thermistor located on the motherboard. The box
temperature is not controlled in the Model 300M. The temperature is measured and displayed as
a TEST function on the front panel (see Section 5.1). The alarm limits can be set via an RS-232
port command.
9-1