How does the ESD system control the power on and off of solenoid valves?
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Although I can understand and explain on-site that the ESD system controls the valve’s air circuit by turning the solenoid valves on and off, thereby achieving an emergency shutdown, how exactly does the ESD system control the on and off state of these solenoid valves? Also, in an ESD system, if the flow rate drops to the level that triggers the self-protection mechanism, causing the solenoid valve to lose power – are there measuring elements (flow meters) involved in this process, and what other components are part of it? How is this low-flow information transmitted to the ESD system, causing it to respond and thereby act on the valves on site?
:L:L Seeking expert help: L Does anyone know what the answer to this question is? I want to know too
How does the ESD system control the power on and off of solenoid valves? It’s just like a control system. Of course, safety must be taken into account.
That’s right; the ESD system falls under the category of safety instruments. When the detection parameters at the site reach the set values for interlock, the DI card outputs a 0 signal, which causes the solenoid valve to lose power and thus release air, shutting off the gas supply. Depending on the characteristics of the valve – FC or FO – the valve will act accordingly, thereby achieving the purpose of protecting the equipment. A typical feedback circuit consists of these components: sensing elements and transmitters. For AI applications, a safety barrier is required, while for DI applications, relays are needed. The signal then reaches the card in the controller, where it undergoes logical processing; after that, the card sends a signal to the relay, which in turn connects to the solenoid valve and thus to the valve itself. The ESD system requires certification, that is, to ensure a certain level of operational reliability; therefore, the control system is unable to meet the requirements regarding ESD response time and high reliability.
What do DI and AI refer to respectively? ? ? ? ? ? ? ? ? ? ? ? ? 、
Uh, isn’t the person upstairs an instrument technician? DI digital input, AI analog input. Simply put, the ESD system controls the energization and de-energization of solenoid valves by controlling relays, which are located in the DCS cabinet. The low-flow signal can be calculated in ESD; the typical value is provided by process engineers or design institutes.
The ESD system controls the energization and de-energization of solenoid valves by controlling relays. So how is it controlled? What is the input of a relay? What is the output then?
After logical operations in most systems, the DO signal is at 5V; this voltage is applied to the coil of the relay. The normally open or normally closed contacts of the coil are connected to 24V. The 24V circuit is connected to the solenoid valve on site through a safety barrier, and this voltage is used to control the opening and closing of the valve on site. Thus, when the DO output is 0 or 1, it controls whether the valve on site is open or closed.
DI: Digital input; DO: Digital output; AI: Analog input; AO: Analog output
DI: Full form is data input, which means data entry； AI: Full form: artificial intelligence, which refers to artificial intelligence