Recent content by Fil

Hi, ISA initially stood for Instrumentation Society of America ; nowdays it stands for International Society of Automation : it provides "foundational standards-based technical resources for industrial automation" (https://www.isa.org/). ANSI/ISA-5.1-2022, Instrumentation Symbols and...

Please find attached a picture of a free wave radar level transmitter according to latest ISA 5.1 symbology

I understand Ki is expressed in repeat per minute : it's the inverse of the integral time Ti (when this one is expressed in minute). Ts is the controller cycle time which is also expressed in minute. If Ts is too long this may make your control loop become unstable. For a self regulating process...

Hi Faizanzaheer, There are different PID structures. The one you have is called a standard PID (it's the most common one) : I find it pretty convenient. For example if your loop is too nervous (PV tends to cycle), one simple way to calm things down is to reduce proportional, integral and...

In case of positive pump static head, you would have reverse flow through a centrifugal pump below a given RPM limit.

Hi, When using 3 wire RTDs, terminals corrosion may lead to either under-estimating or over-estimating the temperature. 4 wire RTDs are not affected by corrosion as long as electrical continuity is maintained (on the 4 wires). RTDs are more accurate but usually more fragile than thermocouples.

Hi, If your TT allows for 2, 3 and 4 wire RTDs, it should be configured according to the number of wires you decide to use (your TT does not work the same way depending on the number of wires used). With two 0.5 mm2 copper wires, 1.5 m long, your RTD resistance will be overestimated by 0.1 ohm...

Hi DaraghC, Assuming Xw is the amplitude of the deviation step change (starting from zero deviation), the time t elapsed since that step change should be located in the numerator instead of the denominator in the equation : the integral term will actually generate a ramp on the controller output...

Hello Iqbal, No straight run is required neither upstream nor downstream of the valve as far as pipe reducers are concerned. However there should not be any elbow immediately downstream of the valve (some valve manufacturers recommend 20 pipe size of straight run downstream of the valve (40...

Hi Egarces, You can try the tape water level sensor from KM Cable : https://kmcable.com/product/stainless-steel-ruler-tape-water-level-indicator-water-level-sensor-water-level-meter-rc9808/

Hi, I presume the lube oil pump is a positive displacement pump : such a pump must have a discharge overpressure protection device not to break anything. The flow orifice in parallel to the PCV may play that role ; as you suggest, it may also be there to maintain a minimum oil flow.

Hi, Your two control loops should have a different dynamic response time not to fight each other. If you are not too demanding about the accuracy of your pressure control, one way to achieve that would be to use a self contained pressure regulator instead of a pressure control loop, which...

Hi, Are you sure the flow meter is installed upstream of the recirculation line tie-in point (in the present case you do not control the flow rate to the system) ? If you want to prevent the two loops from fighting each other, you should tune them so that one is slow acting compared to the...