Regarding the interlock reset switch
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Dear experts, I would like to ask about the issue of interlock reset: A certain interlock system has a master reset switch; when the interlock activates, the corresponding valve closes. These valve solenoids also have a manual reset function each. So, after the interlock conditions are removed, can the solenoids of each valve be reset simply by pressing the main reset switch? Do the solenoids of these valves also need to be reset one by one? Thank you!
Interlock reset is achieved through software, that is, by not bypassing any conditions to enable the solenoid valve to receive power. By \"resetting\" the solenoid valve you mentioned, you mean that the normal position is used for manual operation; in that normal state, there is no need to make any adjustments
The solenoid valve I’m referring to doesn’t have a manual reset switch on site; the logic diagram shows “MANUAL RESET” – can the general reset button for this interlock be used to reset that solenoid valve? O(∩_∩)O Thank you
In this case, usually after pressing the master reset switch, there is no need to reset individual solenoids; otherwise, the master reset switch would be pointless, right?
It depends on the process requirements; in some operating conditions this is possible, while in other conditions the valve reset switches must be actuated in a specific sequence.
It depends on how it is designed. In some devices, if the reset button on site is not pressed, the reset function in the DCS becomes ineffective; this design is intended to ensure that there is someone on site when the device starts up, and that a check has been performed to confirm everything is in order. A global reset does not guarantee that everything can be reset; in many cases, it only takes effect after the resets at the lower levels have been confirmed.
If that’s the case, then the only way is to look at the logical relationships in the corresponding logic diagram
If it is a manual reset on the logic diagram but there is no manual reset switch on site, then it is the overall interlocked reset button. There are three common ways to reset such solenoid valves; this type of solenoid valve is used as a interlock solenoid valve in the SIS system. The methods for resetting it are: 1) the reset button on the auxiliary control panel in the control room; 2) the manual reset knob located on the solenoid valve itself; 3) an independent reset button installed on-site, which sends signals to the buttons in the control room and auxiliary control panel for logical processing. All three of these have been used in projects, usually configured according to the requirements of the process engineering department.