Problems with control

The I/O list refers to the measurement signals connected to each channel on the input/output cards. You can take a look at the difference between digital quantity and analog quantity at http://bbs.hcbbs.com/thread-133198-1-2.html

This includes the tag number of the field device, the signal type, and the I/O address – in other words, as mentioned earlier, which card and which channel correspond to which field device. There is also the diagram number of the circuit where this signal is located, as well as the diagram numbers of other drawings related to this signal. That’s how it is in our case. Last edited by jbsty on 2008-1-4 16:22.]

Thank you for the replies from the two people above! I learned something new

Could that expert please explain how the I/O lists for analytical instruments, pneumatic valves, and electric valves are determined?

It seems we’re talking about different things. What I’m referring to is the I/O list of the DCS system; the main elements are cards and card channels. The bit numbers can be seen in this list, but it’s not possible to determine what type of instruments or valves they correspond to, and I’m not interested in that either. Only by using the device identifier to check other tables can you find out what kind of instrument it is. When it comes to instruments and valves specifically, what is meant is probably which signals this instrument has and what type those signals are In other words, which parameters of this instrument or valve need to be monitored/controlled, and what types of signals do these parameters correspond to. This is my own understanding; those who find anything incorrect please offer guidance. Regarding the system: analysis instruments have AI, while valves have DI, DO (for on/off status) and AO (for degree of opening)

Hello, friend on the 1st floor! It’s indeed a bit much to ask those responsible for the manufacturing process to handle tasks related to automatic control. I myself specialize in the design, programming, installation, debugging, and commissioning of environmental protection automatic control systems. 1. Automation is designed to serve the process; you should first specify the process requirements. For example, if it is necessary to measure the liquid level in a tank, then there is a need for an analog input signal ； If it is necessary to control the start and stop of a device such as a sludge scraper, then a digital output signal is required ； To determine whether a device such as a sludge pump has started, an analog input signal is required ； If it is necessary to control the opening degree of a certain valve (such as an aeration valve), an analog output signal is required. 2. All of your requirements regarding the engineering process have been submitted – hasn’t every I/O list and analog signal been listed? 3. If there’s a chance for cooperation, feel free to contact me at wangrenzhi@163.com.

Learn a bit, hehe :) :)

Thank you all for your replies! Thank you so much :)

It’s hard to explain this thing clearly, I’d recommend reading books on control engineering instead; it can’t be explained in just a few words

I’d like to add something regarding the 6th floor; if it’s incorrect, please feel free to correct me. Analytical instruments have AI; for electric valves, the feedback signal regarding the valve’s opening degree is DI, while the signal used to control the valve’s opening/closing is DO. Pneumatic control valve: The valve opening feedback signal is AI, while the valve opening (OP) output signal is AO. Pneumatic control valve with solenoid valve: The signal indicating whether the solenoid valve is energized or not is DO; the feedback signal for the valve’s opening degree is AI, while the output signal representing the valve’s opening degree (OP) is AO.

Those upstairs must be clear about this. I would like to ask: for pneumatic valves equipped with solenoid valves, what is the function of the solenoid valve?

Please state the specific problem; many people here are involved in automatic control.