Rosemount 755, Instruction Manual

Page: 5 / 94

C
ONTENTS
748183-H
iii
Rosemount Analytical
November 1997
S
ECTION
4. O
PERATION
4.1 ROUTINE OPERATION ...........................................................................4-1
4.2 EFFECT OF BAROMETRIC PRESSURE CHANGES ON
INSTRUMENT READOUT ............................................................4-1
4.3 CALIBRATION FREQUENCY ..................................................................4-2
S
ECTION
5. T
HEORY
5.1 PRINCIPLES OF OPERATION ................................................................5-1
5.1.1 Magnetic Displacement Force.....................................................5-3
5.1.2 Physical Configuration of Detector/Magnet Assembly.................5-4
5.2 VARIABLES INFLUENCING PARAMAGNETIC OXYGEN
MEASUREMENTS ........................................................................5-5
5.2.1 Pressure Effects..........................................................................5-5
5.2.2 Temperature Effects....................................................................5-6
5.2.3 Interferents.................................................................................5-6
5.2.4 Vibration Effects..........................................................................5-6
5.3 ELECTRONIC CIRCUITRY ......................................................................5-7
5.3.1 Detector/Magnet Assembly .........................................................5-7
5.3.2 Control Board and Associated Circuitry ......................................5-7
5.3.3 Case Board Assembly.................................................................5-8
5.3.4 Isolated Current Output Board (Optional)....................................5-9
5.3.5 Alarm Option ...............................................................................5-9
S
ECTION
6. C
IRCUIT
A
NALYSIS
6.1 POWER SUPPLY.,
±
15VDC ....................................................................6-1
6.2 CASE HEATER CONTROL CIRCUIT ......................................................6-1
6.3 DETECTOR HEATER CONTROL CIRCUIT ............................................6-5
6.4 DETECTOR LIGHT SOURCE CONTROL CIRCUIT ................................6-6
6.5 DETECTOR WITH FIRST STAGE AMPLIFIER.......................................6-7
6.6 FINAL OUTPUT AMPLIFIER ....................................................................6-10
6.7 ZERO SUPPRESSION MODULE FOR ZERO ADJUSTMENT ................6-11