Guide to Fisher ROC FST Programming: Tips and Best Practices for RTUs in Oil and Gas Sector

Question:

When it comes to ROC FST programming for RTUs in the Oil and Gas sector, PLCS lacks detailed information. However, after teaching myself the basics, I decided to create a discussion to assist others. This thread focuses on FST Programming and general Configurations for ROC300, ROC800, FB407, FB408, FB503, FB504, FB103, FB104, FB107 in Rocklink800. FST, or Function Sequence Table, is a method similar to Basic programming but displayed in a spreadsheet format. Here are some common practices to keep in mind: 1. Always initiate each FST with a WT (wait) command and set ARG1 to 1. This step ensures proper execution of the FST during each scan. 2. Comments are not stored in the ROC system. Instead, it is advisable to use LBLs to describe each step and MSG Commands to track the progress, as both are saved in the ROC. 3. After writing new code, remember to save the configuration in the system>Flags section of roclink800 to prevent loss of changes. 4. Typically, FST1 handles shutdown logic, while others focus on different functions. It is crucial to ensure all FSTs are enabled for scanning. Feel free to share your own logic examples for discussion and troubleshooting assistance in this ongoing thread.

Top Replies

In the first scenario, a high-pressure condition above 2000kpa triggers the closure of a valve connected to an analog input (AIN A2), while pressures below this threshold allow the system to proceed to the next shutdown check. Additionally, a High level shutdown is activated by a discrete input (DIN, C1) to close the valve (DOU B9) in this setup, which features self-resetting capabilities. The second example introduces a manual reset button (DIN B15) to the configuration for added control.

In this updated example, I have incorporated Soft Points for added versatility. Soft Points can consist of internal bits or actual values, such as Floating Point. In this scenario, when in a high pressure situation, Softpoint1 Data1 will be set to 1, and once it clears, it will revert to 0. The same principle applies for the high level, but with Softpoint1 Data2. Additionally, I have integrated two analog input values that are subtracted and stored into Softpoint1 Data3.

I'm grateful that I'm not alone in dealing with challenging RTU logic. While our systems may vary, the overall approach remains consistent. While others utilize FBD, I find myself creating code that resembles assembly language. It's comforting to know that others encounter similar difficulties in this area.

I also possess several Bristol Remote Terminal Units (RTUs) utilizing AACOL language, similar to assembly. Fortunately, I have not needed to modify their logic yet due to their standard load. One advantageous feature is the naming convention of data tags, resembling Logix5000 but with a more vintage touch. LOL.

Can "compiled" programs from RTUs be uploaded with the defined point names intact? While our RTUs allow uploads, the resulting code may only show the actual point numbers, similar to losing comments when extracting programs from older PLCs. Reverse engineering is a possible but time-consuming option by analyzing the configuration in the base station PC.

I appreciate the solid advice you've shared, particularly regarding the use of LBLs for step descriptions and MSG Commands for progress tracking. This aligns well with my own experience using ROC FST programming. One additional tip that I have to share is the importance of regularly backing up your program code. It's saved me a couple of times when I've accidentally overwritten crucial sections. Also, depending on system redundancy, ensure to update both primary and secondary RTU to prevent any operational mismatches. Looking forward to learn and assist more in this thread.

Thanks for starting this instructive thread! I've been grappling with FST programming and I appreciate these insights. The use of LBLs and MSG Commands as an alternative to comments saved me few headaches already. I'd also urge everyone to become proficient with FOR and NXT loops, they are quite useful for sequential logic operations. Experimentation is key here! It's a robust system and there's a lot you can do once you get the hang of it.

Thanks for starting this valuable discussion, it's not an easy topic and getting hands-on insights really helps! I totally agree on using LBLs for step descriptions - it's really beneficial when you have to return to a project after a long time and you're trying to understand what you were initially trying to accomplish. And one more tip from personal experience - always double-check your OR operator usage in FST programming. It's common to see people misusing it which can lead to a whole host of synchronization issues in a multi-tasking environment. Also remember to critically analyze the necessity of each block in your logic. Optimization can greatly improve the processing speed of the whole system!

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Frequently Asked Questions (FAQ)

FAQ: 1. What is FST programming in the context of RTUs in the Oil and Gas sector?

Answer: - FST, or Function Sequence Table, is a method similar to Basic programming but displayed in a spreadsheet format for programming RTUs in the Oil and Gas sector.

FAQ: 2. Why is it important to initiate each FST with a WT command and set ARG1 to 1?

Answer: - Initiating each FST with a WT command and setting ARG1 to 1 ensures proper execution of the FST during each scan.

FAQ: 3. How should comments be handled in ROC systems during FST programming?

Answer: - Comments are not stored in the ROC system. It is advisable to use LBLs to describe each step and MSG Commands to track progress, as both are saved in the ROC.

FAQ: 4. What is the recommended practice after writing new code in FST programming?

Answer: - After writing new code, it is important to save the configuration in the system>Flags section of roclink800 to prevent loss of changes.

FAQ: 5. How should different FSTs be utilized in ROC programming?

Answer: - Typically, FST1 handles shutdown logic, while others focus on different functions. It is crucial to ensure all FSTs are enabled for scanning to ensure proper functionality.

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