About kishore karuppaswamy

Iam Btech having experience in saudi aramco as instrument engineer

Instrument Gland sizes

  • Cable: 1pair x 1.5 mm2 FRLS   11.9 OD 7.3 ID-Gland:  0.5″NPTM   Range 10 to 14

  • Cable: 1pair x 1.5 mm2 FS 13.1 OD 8.5 ID-Gland: 0.5″NPTM Range 14 to 18

  • Cable: 2C x 1.5 mm2 FRLS 11.6 OD 7.3 ID-Gland: 0.5″NPTM Range 10 to 14

  • Cable: 2C x 1.5 mm2 FS 12.8 OD 8.2 ID-Gland: 0.5″NPTM Range 14 to 18

  • Cable: 2C x 2.5 mm2 FRLS 12.4 OD 7.8 ID-Gland: 0.5″NPTM Range 10 to 14

  • Cable: 2C x 2.5 mm2 FS 13.6OD 9.0 ID-Gland: 0.5″NPTM Range 14 to 18

  • Cable: 1T x 1.5 mm2 FRLS 12.3 OD 7.7 ID-Gland: 0.5″NPTM Range 10 to 14

  • Cable: 1P x 1.5 mm2 FRLS 11.9 OD 7.3 ID-Gland: 0.75″ETM Range 10 to 14

  • Cable: 1Px 1.5 mm2 FS 13.1 OD 8.5 ID-Gland: 0.75″ETM Range 14 to 18

  • Cable: 2Cx 1.5 mm2 FRLS 11.6 OD 7.3 ID-Gland: 0.75″ETM Range 10 to 14

  • Cable: 2Cx 1.5 mm2 FS 12.8 OD 8.2 ID-Gland: 0.75″ETM Range 14 to 18

  • Cable: 2Cx 2.5 mm2 FRLS 12.4 OD 7.8 ID-Gland: 0.75″ETM Range 10 to 14

  • Cable: 2Cx 2.5 mm2 FS 13.6 OD 9.0 ID-Gland: 0.75″ETM Range 14 to 18

  • Cable: 1Tx 1.5 mm2 FRLS 13.6 OD 9.0 ID-Gland: 0.75″ETM Range 10 to 14

  • Cable: 10Cx 1.5 mm2 FRLS 18.4 OD 13.1 ID-Gland: 1″ETM Range 18 to 21

  • Cable: 10Cx 1.5 mm2 FS 22.1 OD 15.7 ID-Gland: 1″ETM Range 21 to 24

  • Cable: 10Cx 2.5 mm2 FRLS 19.9 OD 14.6 ID-Gland: 1″ETM Range 21 to 24

  • Cable: 10Px 0.75 mm2 FRLS 23.6 OD 16.8 ID-Gland: 1″ETM Range 24 to 27

  • Cable: 10Px 0.75 mm2 FS 27.9 OD 21.5 ID-Gland: 1.5″ETM Range 30 to 34

  • Cable: 10Tx 0.75 mm2 FRLS 26.6 OD 19.8 ID-Gland: 1.25″ETM Range 27 to 30

  • Cable: 10Tx 1.5 mm2 FRLS 31.3 OD 24.5 ID-Gland: 1.5″ETM Range 30 to 34

  • Cable: 10Tx 1.5 mm2 FS 36.2 OD 29.4 ID-Gland: 2″ETM Range 30 to 37

  • Cable: 20Cx 1.5 mm2 FRLS 21.7 OD 16.2 ID-Gland: 1″ETM Range 21 to 24

  • Cable: 20Cx 1.5 mm2 FS 25.5 OD 19.3 ID-Gland: 1.25″ETM Range 27 to 30

  • Cable: 20Cx 2.5 mm2 FRLS 24.5 OD 18.3 ID-Gland: 1.25″ETM Range 24 to 27

  • Cable: 20Cx 2.5 mm2 FS 27.6 OD 21.4 ID-Gland: 1.25″ETM Range 27to 30

  • Cable: 20Px 0.75 mm2 FRLS 31.1 OD 24.3 ID-Gland: 1.25″ETM Range 30 to 34

  • Cable: 20Px 0.75 mm2 FS 35.6 OD 28.8 ID-Gland: 2″ETM Range 41 to 46

  • Cable: 20Tx 1.5 mm2 FS 52.6 OD 42.2 ID-Gland: 2.5″ETM Range 53 to 61

  • Cable: 40Cx 1.5 mm2 FRLS 28.4 OD 22.0 ID-Gland: 1.25″ETM Range 27 to 30

    Cable: 40Cx 1.5 mm2 FS 32.8 OD 26.4 ID-Gland: 1.5″ETM Range 30 to 37

  • Cable: 40Cx 2.5 mm2 FRLS 31.9 OD 25.3 ID-Gland: 1.5″ETM Range 30 to 34

  • Cable: 40Cx 2.5 mm2 FS 35.7 OD 29.3 ID-Gland: 2″ETM Range 37 to 41

  • Cable: 5Px 0.75 mm2 FRLS 18.0 OD 12.7 ID-Gland: 1″ETM Range 18 to 21

  • Cable: 5Px 0.75 mm2 FS 21.8 OD 15.4 ID-Gland: 1″ETM Range 21 to 24

  • Cable: 5Tx 1.5 mm2 FRLS 24.5 OD 18.1 ID-Gland: 1.25″ETM Range 24 to 27

  • Cable: 5Tx 1.5 mm2 FS 28.3 OD 21.5 ID-Gland: 1.25″ETM Range 27 to 30

  • Cable: 1Px 1.5 mm2 FRLS 11.9 OD 7.3 ID-Gland: 1″NPT Range 10 to 14

  • Cable: K TYPE THERMOCOUPLE COMP  12.5 OD 7.9 ID-Gland: 0.75″ETM Range 10 to 14

    All Cable OD & ID can have + or – 2 in sizes tolerance and cable glands should be stainless steel ,double compression for out door hazardous area ,stainless steel with nickel platingwith neoprene seal neoprene bushing,IP-66 for steel wire armoured cable,complete with locknut,earth tagPVC shroud and nylon entry threads/seal for IP66 ingress protection

    Tolerance is about (+/-)3 %

Tips and tricks in field instrumentation

TIPS AND TRICKS IN FIELD INSTRUMENTATION

  1. For RTD Pt 100 measurement,measure  the resistance across the white and common terminal, then the temperature can be calculated simply by

    Temp=(resistance measured across terminal minus 100)/0.385  or (resistance measured across terminal minus 100)multiplied by 2.6

for example

if the resistance across white and red terminal is 126 ohm, then

the temperature measured is 26/0.385=67.53 degree centigrade or 26 multiplied by 2.6

26*2.6=67.53

 This follow the same eqn, R=Rₒ(1+αT) remember that this is only applicable for PT 100 not other types

  1. For calibration of -100 mmH2O to -10 mmH20 range capillary type using pressure pump not vacuum pump

The values for 25%,50%,75%,100% are as follows:

0%————-     -100 mm h2o

25%———–      -77.5 mm h2o

50%——–          -55 mm h2o

75%———         -32.5 mm h2o

100%——           -10 mm h2o

First find the Span=URV-LRV=-10+100=90 

Then divide this by 4 as we are  calibrating for 4 values namely 25%,50%,75%,100%

i.e. 90/4=22.5

then the 4 points can be calculated as follows

0%(4ma)————-     0 mm h2o i. e LP  and HP open to atmosphere

25%(8ma)———–      -0+22.5=22.5 mm h2o (apply 22.5mmh2o to HP side not LP here LP is open to atmosphere.)

50%(12ma)——–    22.5+22.5=44 mm h2o (apply 44mmh2o to HP side not LP)

75%(16ma)———         44+22.5=67.5 mm h2o (apply 67.5 mmh2o to HP side not LP)

100%(20 ma)——           67.5+22.5=90 mm h2o (apply 90 mmh2o to HP side not LP)

  1. Calculation of flow m3/hr from differential pressure  values mm h20 if both ranges are known:

We know that the flow equation is related as follows

Q=k√∆p

Here Q is the rate of flow: k is the Bernoulli’s constant;  and ∆p is the differential pressure

Consider for instance the D.P. transmitter is of range 0 to 120 mm H2O and the DCS range of

0 to 1500 m3/hr

Then the next step is to find the Bernoulli’s constant

i.e. Q=k√∆p

1500=k√120 (here we consider span URV values to find Bernoulli’s constant)

k=1500/√120

k=136.936

Once we get Bernoulli’s constant we can calculate any flow rate if we know the D.P. 

For e.g.

If differential pressure is 90 mmH2O

Q=k√∆p becomes

Q=136.936√90

   = 136.936*9.486 = 1298.9 m3/hr

Thus we can calculate any flow rate if we know the transmitter and DCS range.

4.For K type thermocouple (Chromel alumel) if the mV measured across yellow(positive) and red (negative) is x,then the temperature can be calculated as follows

Temperature=x/0.0397(millivolt measured divided by 0.0397) or x *25.2 (millivolt multiplied by 25.2)

for example if we measure the mV value across yellow and red terminal using a multimeter and found to be 0.397 then temperature can be calulated by

temperature=(0.397/0.0397)=10 degree centigrade or (0.397*25.2)=10 degree centigrade

6.calibration checking of capillary type LT if you dont have any instruments for checking

Suppose that a capillary type LT is mounted on a tank having range of -1200mmh2o as LRV and URV -60 mmh2o and you need to check whether the transmitter is Ok

We know that the transmitter is mounted with HP side to high pressure side and LP tapping to low pressure side,Firstly isolate the process line,vent and drain the process inorder to release any trapped pressure inside the flange.the transmitter will show 0% reading ie(-1200mmh2o),

Now measure the tap to tap length and mark the corresponding 25%,50%,75% and 100% level .Remove the LP flange of the transmitter(with HP flange of capillary intact) and keep it near(parallel) to HP tapping, the transmitter will show 100%.Now lift the LP capillary flange to  25% above from the HP tapping (where we marked before as 25%),now the transmitter will show 75% (not 25%)

Next keep the transmitter LP capillary flange at 50% marking the transmitter will show 50% reading.Similarly when we place at 75% the transmitter will be showing 25%

Finally if we place at 100% marking the transmitter should show 0% that is -60mmh2o

Calibration,theory and initialization of GWR level transmitter Rosemount 5300 and Ktek 5100

1234

5

and the blanking distance or blocking distance is used to ignore an extended nozzle that would otherwise cause a reflected signal at the top of the probe and result in a high level reading even when no product is in the vessel

and the Level offset is used to correct the level output of the transmitter to match the actual level in your tank or vessel.There are two cases when Level Offset can be used. One is to accommodate for a unmeasurable length at the bottom of the probe (a negative offset) The other is to accommodate for the length of the probe being shorter than the actual depth of the tank (a positive offset).

seems confusing but I will make it clear, if physical dip tape  or gauge measures 1200 mmwc and transmitter is showing 1000 then put level offset as +200 mmwc

and if physical dip tape  or gauge measures 1200 mmwc and actual  level is 1400 mmwc then put level offset as -200mmwc then the transmitter display will show 1400-200=1200 mmwc which matches with physical reading……………..means this is a trick provided by the company to match physical reading with transmitter reading