Subject: Seeking Guidance on Validating a Solenoid Gate Valve Expression Hello everyone, I'm struggling to figure out how to effectively validate an expression to meet specific criteria for my solenoid gate valve. Here's the situation: I have a gate valve equipped with two limit switches that indicate whether it is open or closed. In the event that either limit switch fails to indicate the correct position, I want the operator to see "N/A" displayed on the string display. To address this, I’ve set up three STRING tags in my Logix5000 program: A) Closed_String (Closed) B) Open_String (Open) C) NA_String (N/A) Additionally, I've established three output signals for feedback based on the limit switch status: A) Gate_Selection_1.0 (Open) B) Gate_Selection_1.1 (Closed) C) NA (N/A) I've attached a picture of the logic for reference. Can anyone provide insights or suggestions on how to create a string display in FactoryTalk View SE (FTVS) that shows OPEN, CLOSED, or N/A based on which output signal is active? Thank you in advance for your assistance!
Avoid using separate outputs for each case. Instead, utilize an integer system: assign 0 for "Not Applicable," 1 for "Open," and 2 for "Closed." Subsequently, implement a multistate indicator in the View for better visualization and analysis.
I completely agree with the suggestion from rdrast. To integrate values of 1, 2, or 3 into a DINT and a Multistate Indicator, you have the option to utilize bits. Alternatively, you can implement an expression in the connection tab of the Multistate. For example, the expression could be: IF {[MyShortcut]Gate_Selection_1.0} THEN 1 ELSEIF {[MyShortcut]Gate_Selection_1.1} THEN 2 ELSE 0. By using this expression, there's no requirement for an NA coil. Essentially, the expression indicates that if neither the "open" nor the "closed" states are true, then the status is N/A. Here’s a breakdown of the indicator values: 1 represents "Open," 2 signifies "Closed," and 0 denotes "N/A." This approach ensures efficient management of gate states while enhancing clarity in your automation setup.
The MultiState Indicator is an optimal choice for enhancing your user interface. This powerful feature allows you to implement distinct text colors and background styles for each state seamlessly. While animations could be used to achieve a similar effect, utilizing a MultiState Indicator streamlines the process and eliminates redundancy. Personally, I recommend avoiding the expressions method in the connections tab, as mentioned by cwal61, despite its validity. My preference is to maintain a clean and organized interface in HMI or SCADA systems, delegating necessary tasks to the PLC. Minimizing the amount of “scripting” or expression evaluations in FTVS applications not only accelerates screen update times but also enhances the overall user experience for viewers.
User rdrast advised against utilizing individual outputs. Instead, he suggested using an integer value: set it to 0 for Not Applicable (N/A), 1 for Open, and 2 for Closed. Then, incorporate a multistate indicator in the View section. User cwal61 agreed, recommending the use of bits to move values 1, 2, or 3 into a DINT and connect it to a Multistate Indicator. Alternatively, he proposed using an expression in the Connections tab of the Multistate Indicator. The expression could look like this: **IF {[MyShortcut]Gate_Selection_1.0} THEN 1 ELSEIF {[MyShortcut]Gate_Selection_1.1} THEN 2 ELSE 0.** This expression allows for a streamlined approach without the need for a separate N/A coil. It effectively communicates that if the gate is neither open nor closed, the status is marked as N/A, with the following definitions: 1 = Open, 2 = Closed, and 0 = N/A. User daba emphasized that the MultiState Indicator is the optimal choice, offering the advantage of different colored texts and backgrounds for each state. While animation could achieve similar effects, it would be a redundant effort since all this functionality can be seamlessly handled by a MultiState Indicator. Personally, I prefer to avoid the use of expressions in the connections tab, as cwal61 suggested. Instead, I aim to keep the HMI or SCADA interface as uncluttered as possible by delegating necessary tasks to the PLC. The reduction of scripting or expression evaluations in FTVS applications leads to faster screen refresh rates and enhances the overall user experience. Thank you all for your invaluable assistance! I successfully implemented the MOV command along with a couple of DINT tags, and the multistate display is now functioning perfectly for my needs. Your input was greatly appreciated!
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Answer: - `Closed_String` for the "Closed" status. - `Open_String` for the "Open" status. - `NA_String` for the "N/A" status when neither of the limit switches correctly indicates the valve position.
Answer: - `Gate_Selection_1.0` to indicate the valve is open. - `Gate_Selection_1.1` to indicate the valve is closed. - `NA` to indicate that the status is not available (N/A), typically when there's a discrepancy in limit switch feedback.
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