Dear experts, why are the signal lines on either side of the diamond symbol in the image different? Does anyone know and can explain it? Thank you!
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Dear experts, why are the signal lines on either side of the diamond symbol in the image different? Does anyone know and can explain it? Thank you!
The dashed line represents the electrical signal (which can be considered a hard connection, i.e., wires), while the dotted line denotes the internal wires (which can be considered a soft connection)
So which lines does the internal line refer to, between which ones?
S is the solenoid valve installed on-site. The diamond symbol represents the interlock logic module within the SIS or DCS system. On the right side of the diamond, there is an output signal from the DCS control module FIQS103 – which is likely a flow accumulation logic module. This signals forms part of the system’s internal logic chain; after being processed and evaluated by the interlock logic module inside the diamond, a control signal (0 or 1) is generated and sent to the solenoid valve on-site, thereby enabling or disabling power supply to the solenoid valve in order to control the three-way valve connected to it
Thank you so much, brother! :handshake
Dashed lines represent signal wires, while solid lines indicate direct connections within the equipment (including those in the control room or cabinets). .
The definition of signal wires in HG/T20505 2014 is described very clearly.
Thank you very much. Then I would like to ask what the diamond in the diagram represents? Why are the two sides of the diamond different signal lines? I’ve read the standards, but I still don’t quite understand them
In HG/T 20505 2014, a diamond box represents a logical quantity. In the diagram, I-103 represents a logical value driven by FIQS-103. The line on the left side of the diamond shape (with a small circle) indicates the data link, through which the logical value generated by FIQS-103 is transmitted to I-103. The dashed line on the right side of the diamond shape I-103 represents an electrical signal that drives the three-way solenoid valve, thereby closing the cylinder valve XV-103 (FC). The three-way solenoid valve can also be actuated remotely via HS-103.
I have more questions and need your guidance. 1. What does a logical value mean? Which part does it refer to in a DCS system? 2. Does the item marked with a circle inside the box refer to the controller? Thank you so much for your answer to the previous question!
A logical quantity is a quantity that has two states, such as 0/1, closed/open switch state, or high/low voltage level. In FIQS-103 in the figure, the ‘S’ (Switch) denotes a switch. It is speculated that when a certain amount of flow has accumulated, the state of this switch changes (for example, from open to closed), and this information is transmitted to I-103; I-103 then activates the three-way solenoid valve to close cylinder valve XV-103 (FC). The three-way solenoid valve can also be actuated remotely via HS-103. Note that the ‘S’ (Switch) in FIQS-103 in the diagram is a logical quantity in the DCS, representing a general-purpose switch.