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Table 1A-1 on page 11 of ASME MFC-3M (2004).

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...

Thanks for the replies so far. In my application the valve discharges seawater overboard so I believe pressure relief is the correct scenario. There is no regulating valve in this system which is what I believe the manufacturer is referring to as the "main valve". I understand this to be a...

Hi TenPenny thanks for the reply. Not exactly, if the system pressure drops when the valve is closed due to demand then it isn't really maintaining constant discharge pressure. Thanks

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...

Thank you this was really helpful.

Thanks controlnovice. On the DCS systems that don't support changing of engineering units is it just assumed that 0 to 100% output of the primary controller represents 0 to 100% of the the secondary controller measured variable? I.e. if the secondary controller measured variable is 0 to 50...

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)?

Thanks for the replies. I was reading about the DeltaV SoE and it suggested that the DeltaV controller has a special memory buffer for SoE. Is it always required that the PLC/controller supports SoE? Are you generally restricted to the PLC/controller manufacturers SoE application or are there...

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...

Hi thanks for your reply. There are a few things I didn't mention in the original post. Firstly, some other options were considered such as replacing the meter with one suitable to achieve the required turn down. As is normally the case the solution I described is preferred since it is a...

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...

Thank you so how about on a DHCP enabled network? Is it possible for the DHCP server to lease more than one IP address? Or how about simultaneously having a DHCP leased address and an address set on local machine?

Thanks for your reply, I'm not sure exactly what you mean by transient ground offsets but your response seemed to suggest that both sides were grounded, just at different points. In this case, I can kind of understand why the output side may be grounded to prevent the output voltages floating...

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...

Thank you for the response