Answer / suresh xavier

there are two parts one is the sensing part and other is
converter. sensing part contains zirconium and heating
mechanism. the main caractristic of Zr. is at higher temp.
(= 750 deg.) the proprty of Zr., it allows the O2 ions to
conduct. to maintain the Zr. at 750 deg. normally we use
platinum electrode on the both side to create a heating
mechanism. when the probe is placed in the flue gas path one
side of the probe will maintaine the span gas (instrument
air contains 21% O2) and the other end is in the flue gas
path contains unknown % of O2. thus it will create a diff.
partial O2 on the each side of the cell. electrode in
contact with higher O2 pressure act as -ve electrode and it
will create an emf. the coverter pck that emf and using the
calibration produce the % O2.
calibration.
for zero calibration use zero gas (0.98% O2 ~~ nitrogen gas)
is used
for span we use 21% O2 (instrument air)

Answer / arsi vadher

what is out in MV and % of oxyzen when on Both side pressure is Atmospheric?

Answer / navneet jain

900 mv and oxygen 0 %

thermocouple output is AC OR DC??

17 Answers  

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What is the SCAN time of a DCS/PLC? What is the typical value for scan time of DCS and PLC?

6 Answers   Essar, Gasco, Siemens,

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What is the Flow rate ?

2 Answers  

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We do have a problem in the company that is one PT connected to PlC which is mean 1 out of 1 in PLC system we do have the PAHH is 55 mbar and PALL 8 mbar with a timer of 15 sec for the PAHH the problem started when PAHH goes more than the set point which is 55 it reached up to 71 but due to timer doesn't trip . We force it and we checked everything nothing there . We replaced the transmitter problem still there the reading goes more than the 55 bar the range for transmitte is 0- 60 mbar . So we did loop check , aculaizing valve , wiring all are okay . What the possible causes for this ???

2 Answers   National Petrochemical Company,

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Why we used cage in control valve?

8 Answers  

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how to calibrate transmitter

3 Answers   Sabic,

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What is PLC(programmable logic control)?

1 Answers  

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What is the difference between Error and Offset.

1 Answers  

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what are the documentation and instrument identification system used to identify the correct device to be calibrated? name atleast three.

1 Answers  

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in natural gas indirect water bath heater,how to prevent the problem of backfire from firetube during ignition...becoz of this backfire performance of wbh is going low.

0 Answers  

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which instrument is used to study the structure of phloem and xylem tissue?

1 Answers  

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why do we use 4-20mA as o/p and why don't use 0-20mA or 5- 21mA?

3 Answers  

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