Is there anyone who can program?

The alarm for the rate of change in pressure drop can be implemented in the program by following these steps: 1. Define and initialize variables: define a variable named pressure to store the last read pressure value, a variable named last_time to store the last reading time, and a variable named speed_rate to store the rate of change. Initialize pressure with the current pressure value, and last_time with the current time. 2. Read pressure values in a loop: Use a loop statement to read the current pressure value at regular intervals (e.g., every 1 second), and record the current time. Then, the pressure change amount delta_pressure and the time change amount delta_time (the difference between the current time and the previous reading time) are calculated, and the rate of change is determined using the formula speed_rate = delta_pressure / delta_time. 3. Determine whether to trigger an alarm: Compare the current pressure value and the rate of change with the set thresholds; if the rate of change exceeds the threshold, an alarm message is generated. Here is an example of pseudocode implementation: pressure = current_pressure last_time = current_time while True: current_pressure = read_pressure() current_time = get_current_time() delta_pressure = abs(current_pressure - pressure) delta_time = abs(current_time - last_time) speed_rate = delta_pressure / delta_time if speed_rate > threshold: print(\"Alert: The rate of pressure decrease exceeds the threshold!\") ") pressure = current_pressure last_time = current_time sleep(1) # Wait for 1 second before continuing to read the pressure value.

I have a question too. There is no flow meter installed at the outlet of one of the measurement tanks. The liquid level is required to drop to a set value within 1 hour, through PID automatic control via a control valve. Which one, give me some ideas?

To become familiar with a DCS system, one needs to read the manuals thoroughly and understand every module in detail. Reference: Yokogawa: Velocity Limiter Block (VELLIM) module. Central control: VLM module.

The system originally had an alarm for the rate of change, but it was calculated on a sampling cycle basis. If the requirement is: \"Decrease by 0.5 MPa within 5 minutes, with a rate of change of 10%; an alarm should be triggered if this rate of change is exceeded.\" 1. The decrease of 0.5 MPa within 5 minutes, with a rate of change of 10%, is converted into a value per sampling period. 2. Use the line chart module. 3. Program by yourself.

The simple solution is to spend some money and have the DCS manufacturer’s engineers reconfigure and program these control points. It is necessary to clearly state the requirements one has and the current operating conditions to the other party.

If the concentration remains stable, considering adding a differential pressure level gauge could be an option, thus turning it into the problem addressed by the original poster. For closed-loop control, a sensing element is required; typically, this is used to detect level, flow rate, or pressure. A typical question; looking forward to other approaches

Is the rate of dropping from 1MPa to 0.5MPa 10%?

Controlling the liquid level has no direct relation to whether a flow meter is installed or not

Yes. Those available in the DCS system

The idea isn’t good; if there’s no flow meter, then install one :)