Answer / jp

Normally, all instruments to be grounded to clean earth (should be less than 2 Ohms). Whereas Electrical earth resistance might be more than this. So Instrument earth pit to be seperate from electrical earthpit.

Answer / sam

The internal screen is always floating at the instrument.
This means we just put some heat shrink on it to seal it and
then tie it off inside the instrument and just let it lie
there. The overall screen (braiding surrounding the cable
just below the pvc outside)will be in contact with the gland
once you have installed the gland. On the gland thread you
install a copper gland ring and a red IP washer, and the
gland then are attached to the instrument. From the gland
ring you use a six mm bolt and nut with copper washers to
attached a small diameter earth wire (about 4 to 6mm is
fine). This earth wire is then attached to the outside of
the instrument at the earth connection point on it's
housing. Every instrument will have this earth connector on
the outside of it's housing. From there you attached another
earth wire to the earth boss nearby. This boss is normally
just a piece of round bar about 40mm in diameter and about
30mm long and tapped in the middle that is welded to the
structure close by, specially for this earthing of the
instruments. Again it is better to use copper washers. If no
boss is available you can use some other point on the
structure as well like a stainless steel cable tray for
instance but the earth boss should really be part of the design.
On the other side of the instrument cable at the RTU the
internal screen in attached the instrumentation clean earth.
The dirty earth is used only for electrical equipment.
Good luck

what is unit and element of viberation?

1 Answers   Kentz, KOC,

---

Hi Friends i need Electronics&Instrumentation Engg question papers for BARC written test by coming 20th May 2008 pls post ur use full info to kkumarei@gmail.com. Or for suggestions pls give one missed call to 9962122264

0 Answers   BARC, Wipro,

---

I am working in a process industry, in that there are several sections devided in the SCADA screens and individual sections may START independently. But sometimes i am facing problem i.e, if section 2 Stopped by the operator immediately Section 1 or Section 3 or Section 4 is getting stopped can you expain the reason behind this?

5 Answers  

---

if i want to make a zero trim for mass flow meter the pipe line should be empty or i need to make it full? i really need the answer pls help me

2 Answers  

---

why any measurement made interms of pressure is more accurate ? to be more precise most of the flow velocity is made interms of pressure and it is accurate. what is the reason behind pressure measurement being accurate ?

0 Answers   NATPET,

---

what is the function of 3 way manifold valve in a closed loop system?

1 Answers   Emerson,

---

can anyone tel the syllabus or previous year question paper for BHAVINI(EIE)2014.

0 Answers   Bhavini,

---

Is wet leg type system nessesary to measure water level of steam DRUM? How the transmitter is calibrated to measure this level?

0 Answers  

---

define SIMULATION a and what is the need of it

3 Answers   Siemens,

---

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  

---

how the 2.5bar pressure able to control the 40bar steam

8 Answers   IBM, PAFL, Thirumalai Chemicals,

---

what is axial shift n what is differential expansion in turbine? how many sensor probes r mounted for this n how it works?

2 Answers   Apple,

---