Seeking help with instrument symbols in PID diagrams
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I’m asking the experts here: what do those gauge symbols in the picture represent respectively? (PB,II,SC,YL,FL)
PB stands for pressure transmitter, and II stands for indicator.
The last edit to this post was made by hanhaigang128 on 2024-3-22 at 16:20. PB should refer to a push button, i.e., a button used for starting or stopping processes, typically found on the screens of DCS or PLC systems； II is the current display ； SC is used for adjusting the motor speed, by providing a frequency-control analog signal of 4-20mA or 0-10VDC to the inverter ； YL is the motor operation signal from MCC ； FL is the motor fault signal from MCC; for details, refer to the legend on the first page of the PID diagram.
PB should represent the start/stop of DCS; HS is used as the standard for this. II indicates the current displayed by DCS, SC represents the frequency setting, YL denotes the operating status, YI is used to indicate a fault condition, and FI is also used for indicating faults
What signals are required for the motor? First, there are the input signals: the current level, which is obtained from a current transformer; the fault status, which is detected via the normally closed contacts of a thermal relay – a fault signal is generated when these contacts open due to heat. There is also the frequency control input signal mentioned earlier, as well as the input signals from the buttons used to start and stop the motor. There are two such input signals. The other types of signals are output signals. As for the operating status, it can be determined by measuring the current levels of the three phases using transformers, thereby indicating that the motor is working properly. Additionally, there are signals that indicate the motor’s status and which are sent to the status indicator lights. There may also be information regarding voltage, the temperature of the coil windings, vibration, the temperature of the lubricating oil, and the temperature of the bearings, among others. I welcome any criticism, suggestions, or additional information from those with more experience.
The PID should have a home page image, and the legend should include explanations