Troubleshooting Differences in Values Displayed Between Kepware and iFix OPC Servers: Scaling Options for DB23;REAL130

Question:

I have limited knowledge about the simaticnet OPC server, but I am familiar with Kepware. In the PLC, I typically only scale raw to engineering, but Kepware does offer the possibility of scaling as well. The tag configuration in iFix for this specific tag is as follows: CPU;READ;DB23;REAL130;S7:[OPC_1]. While using OPC Scout V10, I noticed that there is no scaling information available for DB23;REAL130. Is it feasible to scale this tag? Am I searching in the correct location? My main concern is determining why there is a discrepancy in the values displayed between Kepware OPC and iFix. Despite using two distinct OPC servers with the same source (S7 PLC), the values differ. Without scaling in iFix or Kepware, I am exploring the simatic configuration for answers. I hope this explanation is clear, and I appreciate any guidance you can provide. Thank you in advance!

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I am unfamiliar with scaling tags in Simatic Net, and I am unable to locate information on this topic. In a discussion on Net.dbptx, the focus is on determining the discrepancy between values from Kepware OPC and iFix. Despite both pulling data from a common source (S7 PLC), the values displayed are dissimilar. It would be helpful to see screenshots illustrating these differences, as well as an online screenshot from a watch table in STEP7 featuring the corresponding variables. This visual comparison can provide insights into the root cause of this discrepancy.

Thank you Jesper for your assistance. Unfortunately, I was unable to uncover the root of the problem. I will continue my search for another possible cause and provide an update once I have identified it. Goodbye for now!

JesperMP mentioned that they are unfamiliar with the scaling of tags in Simatic Net and would like to see some screenshots highlighting the differences. Additionally, they are curious about online screenshots from a watch table in STEP7 displaying the same variables. Examining specific values in these screenshots could potentially offer insights. In my opinion, SimaticNet primarily functions as a data transfer tool rather than an OPC server package. It facilitates communication with S7 PLCs through various protocols, with OPC being one of the supported data sinks.

Hey @dbptx, sharing the requested screenshots could bring clarity to the situation. This may help create a better understanding of the issue at hand.

From what you've described, it's clear you've already done quite a bit of troubleshooting. One possibility could be that the scaling in Kepware and SimaticNet OPC servers are being set differently or not at all. You mentioned you usually do scaling at the PLC level, so there could be a mismatch happening there. Also, ensure that the communication settings in both OPC servers are identical - this also could cause different readings. Regarding finding the scaling for DB23;REAL130 in OPC Scout V10, you're probably on the right path but remember that this detail might be hidden within the PLC configuration itself rather than in the software. Remember, troubleshooting often starts by cross-checking every parameter against each other, including those that initially seem unrelated. Hope this helps and keep us updated on your progress!

Hi there! It sounds like you're going down the right path by examining the Simatic configuration. From what you've provided, it looks like your tag in iFix is reading directly from the OPC server. This suggests that if any scaling is being done, it might be happening in the PLC or Kepware, not in iFix. If you aren't seeing any scaling set up in iFix or Kepware, then the discrepancy might arise from the way each server interprets the raw data from the PLC. I would suggest taking a look at how each server handles data types and conversions. Furthermore, checking how Kepware and SimaticNet are reading that specific data block could shed light on the issue. Ensure for potential offset in the data block reading between both servers too.

Your situation sounds tricky! In my experience, discrepancies between two OPC servers for the same source can be due to various reasons beyond just scaling issues. Server update frequencies, timestamp approaches, and even purely OPC server software differences can account for differing displays. Perhaps try checking the data scan rate or browser cache settings in both Kepware and iFix? About your question on Simaticnet OPC - yes, it's entirely possible to scale a tag directly in the server, provided it follows the appropriate datatype format. You might have to dig into the tag property details, though. But first, I'd recommend ruling out other potential causes of the discrepancy.

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Frequently Asked Questions (FAQ)

FAQ: 1. Is it possible to scale the tag DB23;REAL130 in iFix if no scaling information is available in OPC Scout V10?

Answer: Answer: Yes, it is possible to scale the tag in iFix even if there is no scaling information available in OPC Scout V10. You may need to configure the scaling settings within iFix itself.

FAQ: 2. Why are there differences in the values displayed between Kepware OPC and iFix for the same source (S7 PLC)?

Answer: Answer: Discrepancies in values between different OPC servers could be due to how the servers handle data processing, scaling configurations, or other settings. It is essential to check the configuration settings in both Kepware and iFix to ensure consistency.

FAQ: 3. Should I explore the simatic configuration to address the discrepancy in values between Kepware and iFix?

Answer: Answer: Yes, exploring the simatic configuration for the source PLC can provide insights into potential reasons for the value differences between Kepware and iFix. Checking the PLC configuration and communication settings may help identify the root cause of the discrepancy.

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