【2025 Control System】Activation/Deactivation of Interlocks in Emerson DCS Systems
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The Emerson DeltaV control system can consist of multiple servers, which allows the system to be divided into various domains. Each domain can be composed of an independent server, a system network, and multiple field control stations, enabling relatively independent data acquisition and control functions. Operator stations and advanced computer stations can log in to different domains via domain names to perform operations. The network of the DeltaV control system is divided into three layers from top to bottom: the management network, the system network, and the control network. The system network enables the interconnection between the engineer station, operator station, system servers, and field control stations, while the control network facilitates communication between the main control unit and the process I/O units.
Specific steps for enabling/disabling interlocking: Note: After the engineer station is started, log in to WINDOWS using the following account and password. Account: administrator Password: deltap After entering WINDOWS, wait for the following screen to appear, then select ADMINISTRATOR and enter the password deltap again, followed by selecting the WINDOWS desktop. (1) To check whether the instrument device is equipped with interlocks or to determine what types of interlocks it has, follow the steps below. 3.1.1 First, go to the Start menu and navigate to DeltaV Explorer using the following path: “Start Menu\DeltaV\Engineering\DeltaV Explorer” (see Figure 3-1-1). You can also click “Run” on the Start menu, enter: exp, and press Enter to access DeltaV Explorer. (See Figure 3-1-2)
3.1.2 After opening Explorer, press Ctrl+F. Enter the instrument tag you are looking for in the search dialog box; after clicking Search, all configuration information containing that name will be displayed in the box below. Double-click the option with Type set to Control Module, and the instrument configuration module you are seeking will appear in the menu on the left. Right-click on this module and select the References option, as shown in Figure 3-1-3.
3.1.3 If the text “is used by” appears in the pop-up window, it indicates that this instrument is being called by other programs (usually through interlock mechanisms). The method described in 3.1.2 can be used to identify the modules that are calling this instrument, as well as to examine the associated interlock logic. As shown in Figure 3-1-4 below, 2921PSA-1230A is called by 1-BT-1 and C-292113-1.
(II) Disabling/enabling interlock conditions on the operation screen 3.2.1 Disabling interlock conditions on the operation screen. Open the detailed panel of the device for which the interlock stop condition is to be removed, click the corresponding box next to the interlock condition that needs to be lifted; when a √ appears, it indicates that that interlock condition has been removed.
3.2.2 Enabling interlock conditions on the operation screen: The method to enable interlock conditions is to directly click the checkbox corresponding to the interlock; once the √ symbol disappears, it indicates that the interlock has been enabled. Interlock release/activation is carried out within the program, and there are three ways to do this. Method 1: Put the program in Online or Debug mode, locate the condition block (CND) for which the interlock is to be disabled, and set the DISABLE parameter of this condition block to “1”. To activate this interlock, the value of DISABLE in the mandatory condition block (CND) must be changed from 1 to 0.
Method 2: Put the program in debug mode, select the Interlock Stop Condition First Occurrence block (BFI). In the left-side property bar, find the input (IN_D*) corresponding to the interlock that needs to be disabled. Right-click on it and choose Force Input; in the dialog box that appears, enter “0” for Value and click OK to disable the interlock； To activate it, right-click on this input parameter and select Remove Force Input to enable this interlock.
Method 3: Put the program in debug mode, select the DC block or PID function block of the device for which the interlock is to be disabled. In the left-side property bar, find INTERLOKE_D or TRK_IN_D corresponding to the interlock that needs to be removed. Right-click on it and choose Force Input; in the dialog box that appears, enter “0” for Value and click OK to disable the interlock； To activate it, right-click on this input parameter and select Remove Force Input to enable this interlock.