Instrument
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May I ask? The part in front was drawn by myself, while the part behind was modified by someone else; what do the additional symbols mean?； There is also a level gauge on the tank; why was LI 107 changed to LT107 in the previous diagram?
LI107 refers to level indication, while LT is level transmission. I is the interlocking function. For the functions of specific symbols, refer to the explanations of graphic symbols and textual codes
LI stands for level indication, while LT refers to level transmission. By making changes to the diagram below, it will show a level system with alarms and interlocks.
LI107: “L” stands for liquid level, and “I” means display/information. LT107: “T” means transmission/conversion. LISA107: “S” stands for interlock, and “A” stands for alarm. Whether it is a separate or integrated level gauge, on-site level gauges consist of a measurement section and a signal conversion section. Due to the need for signal conversion, the signal first passes through LT107 before being sent to the DCS, where it is converted to LI107 for final display. H, L, and LL next to LISA107 denote high-level alarm, low-level alarm, and very low-level alarm for the liquid level, respectively.
Your original one was a local level gauge; now it has been changed to a remote type that is connected to the DCS. An electromagnetic flow meter has also been added, along with alarm and interlock functions.
A remote gauge at the surface level; dashed lines connect the liquid level to the pump, indicating a interlocking relationship between the liquid level and pump control. The three boxes on the pump represent the three control points of the pump, which may be start/stop, manual/automatic mode switching, feedback, etc.
What you draw is only understandable to you; what is revised is understandable to everyone.
What do the three symbols after M mean?
This post was last edited by Military Emblem 81 on 2018-10-23 at 09:12. ZS: Position switch; XS refers to vibration or displacement interlock action – it depends on the design definition, usually either displacement or vibration (XS P107 likely refers to the displacement of pump shaft 107). II: Current indicator; PG: On-site pressure gauge. ZS P107, XS P107, and II P107 all appear to be position switches, displacement sensors, and current indicators for pump 107. The level of LISA107 controls the start or stop of pump 107
Refer to HG/T 20505-2014 4.1 5.1