Answer / sam

You can install the PT anywhere on the pipe. It is best to
install on top in crude and slurry application but to
measure water you can install any where, even under the pipe.
If you install on the side or under the pipe fill the
impulse line with water then do a zero on the PT before you
do the final span calibration. Also remember that the
calibration you do on the PT must be exactly the same as to
what your DCS or SCADA faceplate have been scaled to. In
other words if you calibrate the PT for 0 to 20Bar you must
make sure the faceplate in the CCR are also scaled to 0 to
20bar.
Good luck

Answer / carl_ellis

If the transmitter is not directly mounted on the
underground pipe, which is not unusual unless there is
vault access, then an impulse tube/pipe has to come up out
of the ground. The pressure measurement will be in error,
low, by the difference in elevation between the pipe's
elevation and the pressure transmitter's elevation.

Suppose the pipe is 2.1m below the grade level and the
pressure transmitter is 1.6m above grade. The elevation
difference is 3.7m.

The measurement is 3.7m or 0.362 bar low.

It is not unusual to have water supplied at pressure
between at 4-8 bar. At 4 bar pressure, an error of 0.36m
water column is a 9% error, a vary large value for an
insturment capable of 0.25% or better accuracy.

The commissioning of the unit should include the
appropriate zero correction to compensate for such a large
error.

Carl Ellis, Measure First

square root calculation for dp flow transmitter? give me a explanation with example

3 Answers  

---

Y to use 4 to 20ma instead of 0-10v

5 Answers  

---

in DCS or PLC we can not put all ai or di,there is calculation through which we can accomodate certain no of digital and analog signal.I need to know that calculation

1 Answers  

---

why the positioner output is 3-15psi

5 Answers  

---

how in the 2 - wire transmitter, 24v supply and the 4ma signal gets in the same path?

1 Answers   Yokogawa,

---

---

please send the hpcl (instrumentation) model placement papers to my mail....

9 Answers   HPCL, Invensys, IOCL, ONGC,

---

How to get Cv of control valve having following parameter ,i.e inlet pressure 4.5kg/cm2 outlet pressure 1 kg/cm2 specific gravity 0.808

3 Answers  

---

WHY WE WILL USE 0-24VdC IN ELECTRONIC CIRCUITS AND INSTRUMENTATION TRANSMITTERS?

3 Answers   Aban Power, Jindal, JSW, Sugar Factory,

---

Where we cant instal mass flow meter.

1 Answers  

---

if we mount flow tube in arrow direction then flow comes in negative & if we mount it another direction then flow comes positive,So what will be the problem

2 Answers  

---

Draw a wheatstone bridge circuit showing supply, meter and 3 wire RTD connection

0 Answers   CCIE,

---

A temperature sensor (RTD) connected via a temperature transmitter is adjusted to give an output of 4ma at 60 deg and 20 ma at 600 deg. This output (4-20ma) from the transmitter is connected to an IGBT-inverter to control a high speed (-12,000 to +12,000 RPM) DC motor. And in the inverter it is programmed as, for 4ma the motor speed will be -3,000 RPM and for 20ma the motor speed will be +10,000 RPM. The question is : If the motor speed is +5,500 (RPM), what will be the temperature? (-sign indicates that the motion is in reverse direction).

9 Answers  

---