Has anybody had any experience using the iterative computations provided by ASME MFC-3M (2004) for orifice plate fluid flow? I can't make sense of Table 1A-1 on page 11 that explains the method. I was hoping somebody might be able to explain or even provide some examples of the calculations in...
I am considering replacing a 6" cage guided globe valve with a 6" back-pressure regulator. The globe valve has a stroke length of around 3 inches whereas the regulator has a stroke length of around 1 1/2 inches. The valve has to provide a very quick response time to limit back-pressure during...
I am trying to understand the operation of a regulating pressure relief valve on a fire pump.
The way I understand is that the valve starts to open when the pump discharge pressure rises above a set-pressure defined by the spring. When the demand changes on the system, i.e. when more deluge...
When a controller accepts a remote set-point in cascade mode from another (primary) controller does the output of the primary controller have to be scaled into the engineering units of the secondary measured value (MV)?
Would somebody mind explaining the differences between a Sequence of Events (SoE) application and a Historian application?
I am aware that some hardware vendors provide I/O cards with SoE features but i'm not exactly sure how this ties into a Sequence of Events recording application or...
I have an application where a vortex flow meter is installed upstream of a flow control valve which is regulating nitrogen flow through a vent system. The upstream pressure is usually constant but varies between 8 to 11 bara. The downstream pressure is approximately 1 bara.
The meter appears to...
Just wondered if anyone can offer some analysis on the following configurations for a 3-wire transmitter circuit? I have recently been presented with an unfamiliar configuration whereby the sensor 0V is distributed back on two leads resulting in a pseudo 3 wire arrangement using 4 lead wires in...
Does anybody have any experience with Codesys? Is there a PLC simulator built into Codesys that could potentially connect to a remote OPC server?
I want to test some PLC applications on a small workstation without physically downloading to a PLC.
I found some stuff on their website about the...
I have two identical DC systems fed from separate DC/DC isolating converters, one converter is fed from a negatively earthed DC supply and the second is fed from a floating DC supply. In both cases the negative of the DC/DC converter supply is tied externally to the 0V or 'common' of the output...
Is it possible for a network adapter to have more than one IP address? in other words can an adapter simultaneously communicate using more than one IP address and on more than one subnet?
If not then on a DHCP enabled network is it possible to change the adapter settings manually to some...
Just out of interest can anybody explain what application layer protocols are used between an OPC client and an OPC DA server? I understand many OPC servers come with a HTTP server for web browser applications however I'm thinking more about Windows based OPC client software such as HMI and...
I have a calculation I need to make based on a value of recorded pressure but need to know the error in the measurement. This could be measured either by Bourdon tube or by diaphragm/piezoresistive pressure sensor.
Typically for pressure sensors the manufacturer will publish an accuracy as a...
Without having practically worked on valve positioners before I would appreciate if someone could confirm my understanding.
A valve positioner will convert an electrical signal to 0-100% of the full pneumatic supply pressure i.e. if the pressure to open/close the actuator is 5 Barg - 0% of the...
I'm in a bit of a dilemma with a intrinsically safe circuit validation cert.
In my circuit, the effective total capacitance is greater than 1% Co. However effective total inductance is less than 1% Lo. Does this mean I can calculate my max. cable parameters by subtracting from Co and Lo as...
I don't suppose anybody could tell me what model of processors are used in common industrial PLC/DCS controllers? I assume the majority are Intel based possibly Xeon for higher end controllers. I heard some old Siemens S7 CPU's use Mitsubishi chips.
I'm more concerned about DCS controllers...
I can use AGA 8 to calculate the compressibility of natural gas from flowing temperature and pressure and the mole fractions.
Which equation of state is then used to calculate density at base conditions in a typical flow computer?
Thanks
Dan
I have to upgrade some old turbine flow meters used for allocation measurement on a 3-Phase test separator. Currently, due to high turndown, there are two turbine meters for each phase (high and low range). I would like to have a single meter for each phase but the high-turndown limits my...
I have a metering application (non-fiscal) for a test separator where there is a requirement to calculate standard volume of produced oil, gas and water from totalised gross volume. The current system monitors gas temperature and pressure and oil temperature automatically and is recorded for the...
Supposing a standard DOL motor control circuit. If the utilization category of the contactor for example specifies it's capability to withstand overload currents as multiples of the rated current. What rating determines the ability for it to withstand short circuit currents in the time it takes...
I'm confused about short circuit currents and how they are used to determine the ratings of equipment within an electrical system.
My own intuition would suggest that that a system must be designed such that any equipment upstream of the short circuit must be able to withstand both the current...
