In split range control, we will control 2 outputs with time interval. Eg :(wit

In split range control, we will control 2 outputs with time
interval. Eg :(with 4-20 ma signal, for 4-12 ma we are
operating one control instrument like valve & for 12-20ma we
are operating other control instrumet (other valve). If we
get a signal of 15ma to first instrument (Valve 1), what
will happened to the first valve, and if we get signal above
20 ma to 2 valve what will happened ?

Question Posted / mohi

3 Answers
6762 Views
I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

In split range control, we will control 2 outputs with time interval. Eg :(with 4-20 ma signal, fo..

Answer / kyle condran

It depends on the setup the 2 above post both correct the following scenario can also be seen sometimes.

Valve 1 set for 4-12mA (100% open @ 4mA and 0% open at 12mA)
Valve 2 set for 12-20mA(100% open @ 20mA and 0% open at 12mA)

For example if you have a temperature control with 2 valves one controlling steam and one controlling chilled water, going into a heat exchange process, when we want to increase temp out of heat exhanger contol signal goes up towards 20mA chilled water valve closes and steam valve opens. when we want to cool the process down the opposite happens and the control signal falls towards 4mA the steam closes and chilled water valve opens.

so 4mA is full on chilled water 20mA is full on steam 12mA is both closed.

lets assume fail open cooling / fail closed heating valve.

as for 15mA on valve 1 depending on where the split range is done, ie controller or valve.

for our example if done in valve it will ignore anything above 12mA and be fully closed.
above 20mA in our example will be ignored by valve 2 since it is allready at 100% at 20mA.

see http://www.contek-systems.co.uk/Documents/split_range_control.htm for the first 2 post

Is This Answer Correct ?

1 Yes

0 No

In split range control, we will control 2 outputs with time interval. Eg :(with 4-20 ma signal, fo..

Answer / romeo

The first valve will open fully open (100%) and the second
valve will open at about 37.5% only.

Is This Answer Correct ?

1 Yes

2 No

In split range control, we will control 2 outputs with time interval. Eg :(with 4-20 ma signal, fo..

Answer / pramod suwalka

1. at 15 ma signal first Valve open fully.
2. at 20 ma signal Both Valve open fully.

Is This Answer Correct ?

1 Yes

5 No

Post New Answer

More Instrumentation Interview Questions

what are different types of cables used in instrumention how to calibrate a level transmitter online ( rosemount )

1 Answers

what is difference between OP AMP and differential amplifier?

5 Answers TCS,

I wnat to practice more online type questions .so will you show them me to take a practice test?

0 Answers VA Tech Wabag,

what is the PID controller?

1 Answers

Steve said that "An eddy-current probe works by passing an alternating current through a coil of wire and measuring the coil’s impedance" while we are using -24 Volt DC , So I am confused about DC and AC. Plz .

2 Answers Jindal, Sadara Chemicals,

y v r connecting 250 ohms resistor in series when u cummunicate with BT in bench calibration?

5 Answers

how to test rotor &stator earth fault in turbine

1 Answers Bhel,

What is the difference between a double acting and single acting positioner? what type of valves use single acting positioners?

1 Answers AquaTech, NamPower, Samson Resources,

What are the difference between mass flow meter, magnetic flow meter and vortex flow meter.

1 Answers

what is zero and span ?

0 Answers

how to calculate flow range in DP tx

1 Answers Karnataka Power,

Which products are available in the Mass Systemswitch and System Manager AC range?

0 Answers

For more Instrumentation Interview Questions Click Here