Discussion on letter combinations for instrument functions
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The final actuator is something like a valve; using V in the suffix makes it easy to understand. Why is Z used for some of them, such as BZ/EZ/IZ/QZ?
This post was last edited by Ku Liang Zhi Le on 2019-7-25 at 12:00. The letter V denotes valves, dampers, and louvers； The letter Z denotes drivers, actuators, and unclassified final control elements. For example, control valves, flue dampers, and ventilation louver doors are denoted by “V”, while frequency converters, hydraulic couplings, electromagnetic tie rods, etc. are denoted by “Z”.
Please refer to \"HGT 20505-2014 Functional Indicators and Graphic Symbols for Process Measurement and Control Instruments\"
What if BZ/EZ/IZ/QZ are valves that are already under control?
According to the provisions of HG/T 20505-2014: B/E/I/Q represent the controlled variables or initiating variables as follows: B: burner, flame； E: Voltage ； I: Current ； Q: Quantity. Are the actuators that control these controlled variables control valves? If a control valve is used to adjust the fuel flow to control the flame, that’s understandable; but how can a control valve be used to control voltage? Control the current with a control valve? Control the quantity with a control valve? It’s a bit confusing.
Then please explain the one that is understandable!
This post was last edited by Ku Liang Zhi Le on 2019-7-26 at 10:48. For example, control valves on the fuel pipeline are used to adjust the fuel flow, in order to control the amount of fuel burned by the burner or the intensity of the flame. Then the symbol for this control system is: flame detector or flame transmitter (such as infrared, radiation, etc.) BE or BT ； The controller is BIC ； The control valve is BV.
I also want to know the outcome of the question raised by the original poster; after reading so many explanations, I’m still not clear