Answer / carl_ellis

Let's assume base metal elements only, since noble metal
elements are so expensive that they are under lock and key;
adequate protection from loss of identification.

For types T, J and K, (and by exclusion, E) the options are

-a spectropscopic assay which will positively reveal the
alloys' composition, but given that the cost of an assay is
proabably 20x times the value of a base metal element, it's
not likely to happen.

- visual identification of a type T by the copper color of
its positive leg which is copper. The alloy leg is a shiny
'metallic' color.

- testing Types J or K with a magnet.
The Type J positive leg is made of iron which has a very
strong magnetic attraction.
The Type K negative leg is made of a nickel alloy which is
mildly magnetic.
Type E is non magnetic, but so are other types.
It can be tricky to distinguish mild attraction on thin
gauge wire.

Testing with a multimeter can be very misleading, because of
the difficulty in determining both the hot junction AND the
cold junction temperatures. Without accurate temperature
values, of what use is a mV reading?

Carl Ellis
Measure First

what is virtual instrumentation

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If a control valve is hunting means means if we are giving 50% to the cv, the cv will open at 51% then slowly slwoly it will reaches 49% , so what to do for solve this problem. The cv is double acting and mounted for anti surge operation, it having 4 nos. volume booster, one sov, one positioner, etc..?

0 Answers   QAFCO,

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How can we say that accuracy of measurement increases by using 3 or 4 wire RTD? because for example: If resistance of RTD element is say r ohms and Resistance of the cable from transmitter to RTD is R ohms And if 4 wire RTD is used, ____._____________________ R ohms | |_____._____________________ R ohms / \ / r ohms \ \ | |______.__________________ R Ohms | |_______._________________ R ohms Then the actual resistance measured will be: Total = r + R/2 + R/2 = r +R Ohms Note: r+R instead of r ohms. hence error

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why we use by pas on a positioner? When can a by pass be not used on a positioner ?

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Please asked me How calculate DCS controller memory.

0 Answers   Yokogawa,

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What is PLC(programmable logic control)?

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IF I WANT TO BUY A THERMOCOUPLE THEN WITCH PARAMETER I LOOK

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2 Answers   IMECO, Voltech,

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need to calculate flow rate with the help of dp range and orifice bore dia and size. range is 0 to 400 inwc and orifice size is 12 inch 150 # rf and bore dia is 7.180 inch. need to calculation for flow rate

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why thermocouple called thermocouple?

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how we can measure the interface level?is it possible to measure interface level with dp or pressure transmitter?

2 Answers  

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