Regarding the issue of opening the instrument pipe port
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What is the difference between the level gauge interface LG (defined by the equipment team) and the level control port LC (defined by the instrumentation team)? Also: What instrument is connected to this level control port? Can it serve as a level control mechanism?
Controlling the liquid level means controlling the feed flow rate or the discharge flow rate. What to use for feeding and what to use for discharging? Will a liquid level interlock be used? It’s worth giving it a try; the instruments will handle it properly
It might be due to different divisions of labor within the design institutes; in our institute, both the level gauges and the control systems are determined by the instrumentation department. Generally, the interface for level gauges is that of local level gauges (such as glass plates), while the interface for level control is usually connected to a level transmitter, which uses its signals to control the opening degree of the control valve, thereby achieving level control.
That’s absolutely correct: the local level gauge is designed along with the equipment, while the interface for the remote level gauge is provided by the instrumentation manufacturer based on the design of the equipment. This post was last edited by bwq on 2009-3-26 15:39]
Generally, for design units, whether it is local level gauges or remote-level meters, the instrumentation specialty is responsible for their implementation. However, at the manufacturing plant, some departments assign on-site level gauges to equipment management, while the gauges are responsible only for remote-level measurement. Therefore, during the design phase when specifying requirements for the equipment, the instrumentation team is responsible for providing the requirements regarding the nozzles for these two instruments. LG (LEVEL GUAGE) refers to an on-site level meter ； LC (LEVEL CONTROL) refers to a remote liquid level gauge.
The local level gauge on the equipment is specified by the equipment itself, while the remote-level gauge is specified by the instrumentation.
The level gauge LG: generally, if it comes as part of the equipment, then the specifications are determined by the equipment itself; otherwise, they are specified by the gauge. In such cases, the display is usually local, though there are also models with remote transmission capabilities； Level control LC is generally part of the entire automatic control system; it is determined by instruments, which may send out analog signals, digital signals, or switch signals.
Amen. It’s best for the brother to go and take a look at the site; it will be clear at a glance. Simply put, LG is connected to the on-site gauge, while LC is connected to the central control panel (remote controller). It’s possible to design two connections on the device itself, with those connections separated using a tee or quarter-turn fitting, or they can be separate connections on the device – the choice depends on the requirements of the process
In some design institutes, it is the equipment department that determines the pipe sizes; in a few large institutions, both the equipment department and the instrumentation department are involved in making such decisions. In such cases, the institute usually sets a specification for the pipe diameter at the liquid level measurement point for the equipment department (which is exactly what the original poster is referring to here). LC and LT are remote control interfaces; in any design institute, it is the instrumentation department that determines these. That’s why the situation described by the original poster occurs.
Specific regulations should be established for the connections of instruments to the openings in the process pipelines, such as the method of connecting the instrument tubes, the selection of pipe diameters, and the boundaries of respective areas of responsibility
They are different; generally, these two openings are determined by process requirements. The level gauge interface LG (specified by the equipment department) is primarily used to connect local level instruments, such as magnetic flip switches. The liquid level control port LC (specified by the instrumentation department) is mainly connected to instruments for controlling valves.
The level gauge is specified based on process requirements, and then the equipment staff installs it in the appropriate location according to those requirements. As for whether it is local or remote, this falls within the scope of control and instrumentation tasks; if it involves the DCS system, then it is necessary to consider the instrumentation specialists’ setup of data acquisition devices and signal transmission lines. If the liquid level is to be controlled and adjusted, it is generally linked to a control valve.
First, the location of the level gauge port is proposed by the process engineering team, and the equipment engineering team installs it at an appropriate position based on the process requirements. On-site, it’s the responsibility of the equipment staff; for remote transmission, it falls under the scope of the instrumentation team, who are responsible for connecting the signal wires.
There is interlocking between feeding and liquid level; as for which instrument to use, it mainly depends on the properties of your material. This should not be difficult to implement