A large butterfly type control valve in a fuel-gas line has been installed in the wrong flow direction. Now, it will be difficult to extract the valve from the pipeline and turn it around because structures in the vicinity have to be dismantled first.
However, the pipeline is not yet 'charged'...
We regularly have heated debates about whether to have a DCS or a PLC for the instrumentation portion of our projects.
Typically, I find that what a DCS can do, a PLC can also do. Only, a DCS is generally costlier than a PLC, for the same I/Os.
In the end, the choice boils down to the whims of...
We want to install a CV analyser in the CO and mixed (i.e., CO+BF) gas lines to a coke oven battery.
Our CO gas has a fair amount of tar residue and also significant napthalene content (about 20mg/Nm3) - which are carry-overs from the byproduct plant.
Can anyone suggest what kind of sample...
I am an instrumentation engineer.
We are doing the engineering for injection of coal tar into tuyeres of a big blast furnace. This is slated to bring down the coke rate in the furnace.
We know that about 30 to 50 kg of coal tar per tonne of hot metal is the norm.
But, the set-point for tar...
I have an application where digital outputs from a PLC will be required to operate a solenoid valve in the field - 800m away(i.e., a cable length of 1600m between the PLC DO terminals).
The solenoid valve is rated 24V DC, 12W and will work upto 22V DC.I want to use a 1.5mm2 copper cable (say)...
I have a basic doubt:
1) What is the advantage of taking differential type analog I/O cards?
2) Does using differential type I/O cards necessarily ensure channel-to-channel isolation?
In one of the process plants for which we are developing the application software, there are electrical (motorised) actuators for continuous control(PID type) of process parameters, like pressure and flow.
The motorised control valves have no position feedback. From the PLC, two numbers of...
We are designing a gas mixing station for mixed gas - from coke oven gas and blast furnace gas.
The required calorific value (CV) of the mixed gas is 3000 kcal/Nm3.
The CV of the blast furnace gas is about 850 kcal/Nm3 and that of the coke oven gas is about 4300 kCal/Nm3.
To describe the...
We are putting up an offer for a walking beam type reheating furnace. The instrumentation part of the bid document specifies that "all instruments and equipment located in hazardous locations shall be explosion-proof or intrinsically safe".
Can anyone let me know which areas (if any)...
I have an application where I have to totalise the flow value of coke oven gas (in a steel plant)in a PLC based automation system. For this, I have a flow transmitter in the field which gives a 4-20mA DC output corresponding to the flow range.
Can I use this 4-20mA signal directly in the...
