Teledyne instruction manual Correct Operation, Thermal Conductivity Analyzer, Model 212R

Thermal Conductivity Analyzer Model 212R

5)Using a screwdriver that has a shaft diameter of 1/8” and a shaft length of at least 6”, turn the “Reactive” balance adjustment all the way counterclockwise (CCW) until the potentiometer stop point is reached. Turn the adjustment back clockwise (CW) 5 full turns to center the adjustment.

6)Turnthe“Resistive”balanceadjustmentallthewayclockwise(CW) untilthepotentiometerstoppointisreached.

7)Slowly turn the “Resistive” adjustment until the output reaches its lowest value. If the reading is negative adjust to the most nega- tive value possible.

8)Turn the “Reactive” balance adjustment slowly CW and CCW to obtain the lowest possible output value. Again, if the reading is negative adjust to the most negative value possible.

9)Repeat steps 6) and 7) until the output value is as low as these adjustments can make it.

10)Detune the instrument by turning the “Resistive” balance adjust ment ½ turn CW. This will bring the signal out of the baseline noise, which could otherwise cause non-linear response at the low concentration end.

NOTE: Due to minute differences between measuring cells and the electronics in the bridge circuit found in vari- ous instruments, some analyzers will have to be bal- anced at a point higher than 10% of scale while others can be balanced even closer to electrical zero. The 10% of scale recommended in step 6 of the procedure is an arbitrary starting point. If the bridge circuit can be easily balanced at this signal level, the procedure should be repeated at a point even closer to electrical zero. Conversely, if balance cannot be accomplished at 10% of scale, the operator will have to select a higher recorder set point for the procedure. In any case, the object is to accomplish dynamic balance with the lowest magnitude of analyzer cutout signal attainable with the analyzer at Range #1 sensitivity.

6.3Correct Operation.

If a stable recording is achieved when the analyzer is operated on zero gas, erratic performance must be attributed to the customers sampling system

20 Teledyne Analytical Instruments