One picture, seeking help
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What is the purpose of S-1201A below HS-12105 in the diagram? Also, is the location marked in red in the diagram a SIS system? Are FT-12105 and FT-12106 dual-fault tolerant? When both flow meter systems are operating normally, can only one of them be selected? Or will an alarm be triggered if both systems are used? What is the function of the signal lines marked in blue in the diagram?
I just checked some information but couldn’t find it. What does this symbol mean?
FICA12105/FICA12107 are for reaction, FT-12105/06/07 are flow transmitters, HS12105 is a button, and FV12105/12107 are air-operated shut-off valves. 1. FFFY-1203 performs a PX/air comparison calculation and uses the result as the set value for FICA12105. FT12105/12106 serve as the inputs for the HS12106 high selector; the selector selects the higher value as the feedback measurement for FICA12105. After PID control, this value is sent to the actuator in order to control the valve opening degree ； At the same time, HS12106 outputs to XA12106 for alarm display. HS12105 is a button; when it is activated, it outputs a high voltage of \"1\", which triggers the solenoid valves FV12105/12107 to open simultaneously as part of the interlock mechanism. And it displays an alarm on XA12106. 2. FT12107 is used as the feedback measurement value for FICA12107; after PID control, it is sent to the positioner in order to control the valve opening degree ； The SP value is determined by comparing the operator with HS12106. Note: On the FICA12105/12107 controllers, there is an H and an L setting respectively; I’m not sure whether this refers to selecting high or low for interlock operations, or something else The above is for reference only; I’m not sure if it’s correct, and I hope someone kind can offer some guidance.
Reply to 3# Instrument Elite: Thank you, expert. The analysis is very thorough. Could I add you on QQ at 894964110? I’d like to communicate with you more in the future.
I have a question for the gentleman upstairs: where can it be determined that FIC-12105 and FIC-12105 are reactive to each other? Are FV-12105 and FV-12107 also air-operated valves? ? HS-12105 agrees with what was said above; it is a button. S-1210A is, in my opinion, the solenoid valve for valve FV-12105; the activation and deactivation of this solenoid valve are controlled through HS-12105. These are just my humble opinions; I hope those with more expertise can provide answers for reference only.
Reply 5# uddmcipyud: There is a “reverse” option next to the controller, so it’s clear that the controller operates in a reactive manner. The direction of the air-operated valve can be determined from the arrow on the air signal line and the arrow indicating the direction of movement of the valve stem.
The two flow transmitters are FT-12105/12106; HS-12106 is a selector switch on the DCS, while FFY-12105 is used for calculating the flow ratio. HS-12105 is likely some kind of button on-site... Nothing else to say
Reply to 5# uddmcipyud 1: Explanation of the word next to fic, reaction. 2. For air control valves, it can be determined from the following points: the valve diagram should show a diaphragm control valve, with air entering at the upper diaphragm head and the valve stem moving downward. Normally it is a gas-shut valve, but it is not excluded that it could be installed in reverse – as a gas-open valve. The terms “air on” and “air off” are used here merely by me to indicate the functional principles shown in the diagram; they do not necessarily mean that it is an air off state. In typical flowcharts, indicators such as FO and FC are used, while icons like S-1210A represent interlock functions. This needs to be determined based on actual conditions, but it can be said that one refers to a relay and the other to a solenoid valve
Reply to 3# Instrument Expert: I would like to ask that if both the HS12106 and HS12105 values fall within the alarm limits of XA12106, how should the operator distinguish between these two alarms?
In the DCS, under the XA12106 alarm light, two descriptions are provided: «Flow Rate Alarm» and «Interlock Button HS12105 Activated»; each description draws its references from its respective functional block. I was wondering if this is acceptable
Reply to 10# Instrument Expert: I wonder if it can be understood in this way – HS12105 is the key point in this diagram. When the conditions for HS12106 and HS12105 are met, it triggers an alarm at XA12106, and at the same time an interlock mechanism is activated, causing both valves FV12105 and FV12107 to open fully.