Questions about PID legend
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This post was last edited by Gentle man on 2024-7-9 at 11:20. Hello, experts. I came across a PID diagram that doesn’t have any legends at the beginning, making it difficult to understand. I’ve come here to ask for your help. Those who know the answer please offer some guidance. My questions are as follows: 1. In the red circle in Figure 1, there should be a orifice flow meter; the pressure is sent to two transmitters, generating two flow signals that are sent to different locations. I’m not sure if my understanding is correct I mainly haven’t encountered such a flow meter. In Figure 2, within the red circle, it seems to be a flow meter as well, but it has a pillow-shaped design; I’m not sure what type of flow meter this is. The external signal 1400-PDIT-1141 – I think it is also a flow meter, but I’m not sure what type of flow meter it is. 3 In the box in Figure 2, what symbol is that? As shown in Figure 4, this falls within the scope of logical operations performed by the host computer. It seems to be a symbol for less than or greater than, with a vertical bar in between; I assume it represents either not less than or not greater than. I’m not sure if that’s correct. 4 What do the 1 in Figure 3 and the 3 wires inside the green circle mean? I assume they refer to axis signals. On the left, 3 represents the vibration signal VT, while on the right, 4 represents the temperature signal TE. Therefore, I assume that 1 refers to the vibration of the pump shaft. As for the temperature signal, it is 2 in Figure 3. What signal is 1400-FV-1161, which is inside the yellow circle? It looks like an icon for a self-acting control valve, with FO written below it; can the pump generate a flow signal? 6. The number 3 in Figure 3 is, in my opinion, a vibration signal; V is the symbol used to represent vibration. 7. The number 4 in Figure 3 is, according to me, a temperature signal – it likely represents a measurement of the temperature of the pump shaft. These are my analyses of these diagrams; there may be inaccuracies or omissions, so I hope experts can help clarify things and provide constructive feedback! ! I truly appreciate it! ! The PID screenshot is as follows
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Hello! Based on the description you provided regarding the questions about the PID diagram, I’ll try to give you some guidance and explanations: 1. Regarding the red circled area in Figure 1: Your understanding is correct. Orifice flow meters measure flow rate based on pressure difference, and the output signals are usually fed into at least one transmitter for signal conversion and transmission; they may be designed with two signal outputs to meet the requirements of different control systems or monitoring needs. 2. Regarding the pillow-shaped symbol within the red circle in Figure 2: this may indicate a special type of flow meter, such as a turbine flow meter or an electromagnetic flow meter; it is necessary to check the detailed model information or specifications of the device to determine exactly what it is. In external signals, “PDIT” usually refers to a pressure differential sensor; however, without further information, it is difficult to determine its exact type here. 3. The symbol inside the box in Figure 2: This symbol is commonly used in logical operations to represent a conditional judgment; your understanding is somewhat correct – it may denote some kind of comparison operation such as “not less than” or “not greater than”. 4. Regarding the green circle 1 in Figure 3: The three wires may represent different types of monitoring or signal wires. Based on your description, it is reasonable to assume that they correspond to vibration (VT) and temperature (TE) signals, indicating that these wires are likely connected to the respective monitoring devices. 5. 1400-FV-1161 within the yellow circle 2 in Figure 3: This symbol appears to be a self-acting control valve. FO usually refers to Flow Output, which may be the flow control signal generated by a control valve based on the control logic. 6. Position 3 in Figure 3: Your judgment is correct; V generally represents a vibration signal (Vibration). 7. Position 4 in Figure 3: This position indeed represents the temperature signal (Temperature), which is used to monitor the temperature of the pump shaft. I hope these explanations are helpful to you! If there are still any points that are unclear or require further discussion, feel free to ask. .
In the red circle in Figure 1, there should be a orifice plate flow meter; the pressure is sent to two transmitters, which generate two flow signals that are sent to different locations. I’m not sure if my understanding is correct I mainly haven’t encountered such a flow meter (this one is for two-out-of-two flow control). In Figure 2, within the red circle, it should still be a flow meter; however, it has a pillow-shaped design. I’m not sure what type of flow meter this is. The external signal 1400-PDIT-1141 – I think it is also a flow meter, but I’m not sure what type of flow meter it is. (Venturi) 3 In the box in Figure 2, what symbol is that? As shown in Figure 4, it falls within the scope of logical operations performed by the host computer; it seems to be a symbol for less than or greater than, with a vertical bar in between. I think it’s a symbol for greater than or equal to or less than or equal to – am I correct? (Correct.) 4 What do the 1 in Figure 3 and the 3 wires inside the green circle mean? I assume they refer to axis signals. On the left, 3 represents the vibration signal VT, while on the right, 4 represents the temperature signal TE. Therefore, I conclude that 1 refers to the vibration of the pump shaft. As for the temperature signal, it’s 5. What signal is 1400-FV-1161 in Figure 3, inside the yellow circle? It looks like an icon for a self-acting control valve, with FO written below it; can the pump generate a flow signal? (It’s a flow rate display controlled by the program above.) 6 The number 3 in Figure 3 is, in my opinion, a vibration signal; V is the letter representing vibration (correct). 7 The number 4 in Figure 3 is, in my view, a temperature signal – it’s likely a signal that measures the temperature of the pump shaft (correct)
5 What signal is 1400-FV-1161 in the yellow circle, the number 2 in Figure 3? It looks like an icon for a self-acting control valve, with FO written below it; can the pump generate a flow signal? (It’s a flow display controlled by the program above.) Isn’t this thing a flow control valve? faulty open
Figure 3 shows that device is a fan, and FV is used to adjust the air volume
This post was last edited by Gentle man on 2024-7-9 at 13:51. First of all, thanks to all the experts for their detailed analyses and explanations! Especially the in-depth analyses from the experts on the 3rd and 4th floors! The expert’s analysis further reinforced some of my understandings and judgments. It seems that the legends in PID charts are very important; especially when the way PID charts are drawn is inaccurate or not universal, they are extremely useful for interpreting such charts! We’re all in the same field; if we put in effort and observe how others solve problems, it can also help improve our own skills
The minimum value is represented by the symbols for Venturi meters, flow nozzles, and flow measurement tubes; no indication of the type of component is present in the diagram.
The flow meter in Figure 1 is a orifice plate flow meter (2 flow meters share 1 throttling element). There are 2 sets of differential pressure flow meter tapping pipelines, each connected to 1 differential pressure flow meter. The signal from one flow meter is sent to process control systems such as DCS or PLC, while the signal from the other flow meter is sent to systems such as SIS for protection and interlock functions.
5 What signal is 1400-FV-1161 in the yellow circle, the number 2 in Figure 3? It looks like an icon for a self-acting control valve, with FO written below it; can the pump generate a flow signal? I understand there are two possibilities: one is variable frequency control, and the other is using inlet guide vanes of the fan to control flow, in both cases without a valve body. The others agree with the comments above.