Urgently need a construction plan for the SIS system for instruments; anything similar to power-on circuit debugging will do
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A SIS system is added to the spherical tank area; the existing continuous level gauges for these tanks (servo and external mounted level gauges, or servo and radar level gauges) are connected to the SIS via DC4–20mA standard signals. The two level gauges associated with each tank are connected to separate input cards, while ultrasonic level switches are connected to the SIS through digital signals, thereby enabling a \"three-out-of-two\" interlock mechanism to shut off the feed valve. The SIS system can transmit liquid level and valve status signals to the DCS, enabling operators to monitor the tank’s liquid level and the status of valves on the DCS. The focus is on system power-up and SIS circuit debugging
Replace the interlocked point with a safety barrier that has one input and two outputs, with one output leading to the DCS and the other to the SIS. As for this choice of three options out of two, it can also be done in SIS. Then, there are several ways for a valve with feedback functionality to send information back to the DCS. A valve with feedback capability can connect the DCS’s output to the SIS, with the SIS then sending signals to the valve; it is also possible to establish a direct communication link between the SIS and the DCS. For valves without feedback to be displayed on the DCS, the SIS needs to output another set of signals to the DCS. In fact, the compatibility between current SIS systems and DCS systems is quite good, allowing for communication between them.
Move the measurement point directly to SIS! If DCS wants to watch, just communicate directly! That’s exactly what we do! If your company has the funds, you can use a one-in-two-out safety barrier!
Both the plans for the 2nd and 3rd floors are viable; we have used them both. If the original plan includes communication between SIS and DCS, then option two is more cost-effective. If there is no such communication between them, using a one-input two-output safety barrier is also a simple solution, and in either case good results can be achieved.