The 1747-L541 processor requires a program to be loaded into the PLC. However, when attempting to download the program via DF1, there is a warning that communication may be disrupted. The PLC communicates with a Panelview 600 via DH+. Upon clicking "Apply changes," communication is lost and the backup capacitor must be drained to reset the unit. Avoiding clicking "Apply changes" during the next download and then adjusting the DH+ address node online still resulted in communication loss via DF1. Screenshots are provided for reference. Is it possible to connect to different nodes on the network via DH+? None of the PLCs on the network are accessible via DF1.
Inspect the serial ports settings within RSLogix, the software in which you are transferring the program.
While examining the serial configuration settings, the only difference I noticed was that my initial program has a baud rate higher than the default setting. I came across a helpful tip in a post from 2003 suggesting to go online with the SLC in Rslogix500. By opening the program, accessing the comm settings, and selecting Who Active to go online, I was able to connect with the processor and save the project. However, I encountered an issue as the PLC wanted to establish a connection via DH+ instead.
While reading through other discussions, I discovered that bits S:34/0 and S:34/5 in my program were set to 1, which was unfamiliar to me. I made the necessary adjustments by changing them to 0 and then downloading the program. As a result, it now autoconfigures to SLC-CH0 without any issues. However, I am unsure about how to connect or upload to other PLCs on the DH+ network. I plan to experiment with the pass-through function using the KF-2 device in RSLinx to see if that will allow me to establish a connection. Perhaps the engineer who set up this system initially used a similar method to connect to the PLCs.
ThomasGruetter noted that the only difference in the serial configuration is the higher baud rate in the original program compared to the default setting. This seems to be the root of the issue. To resolve it, adjust the offline program's serial configuration to align with your current connection. Alternatively, you can download the original program and set up the new connection in RSLinx by configuring the driver.
Recently, I encountered an issue while trying to connect to my SLC504 PLC. After downloading the program with specific settings, I lost communication on DF1-SLC-CH0. Despite closing Linx and reopening without drivers, I still couldn't establish a connection with Device 1770-KF2. It seems that setting the two bits to 1 is necessary, but I'm facing issues with my drivers. It's important to note that there is no DH+ network, only one processor in my test rack. Despite these challenges, I expect to successfully connect to my SLC504.
Your issue does sound extremely complex. To verify, have you checked your cable connections and made sure your configurations in RSLogix and RSLinx are correct? Specifically, your node address on the PLC and in the software configuration should match. If that's all fine, then you may want to consider that the DH+ network could be the main issue. You could try connecting to another device on the DH+ network or slot if possible, as that could help isolate the problem. It could also be beneficial to update your drivers or firmware, or use an alternative communication method such as Ethernet if that is an option. I would suggest looking at consultations with an AB professional if these suggestions do not solve the problem.
It certainly seems like a complex issue you're dealing with. Even though the 1747-L541 processor should technically be able to connect to different nodes on the network via DH+, problems might arise if there's an incorrect node addressing or a physical issue with the network itself. As for your DF1 communication loss, it's possible that there is a mismatch between the communication parameters that are set in the PLC program and the downloading device. If you've already verified all the settings and parameters, I'd recommend checking the physical cable conduction and port conditions. Sometimes, the problem is as simple as a wore down or damaged cable. Solving the issue might involve a bit of trial and error, but keep us updated so we can help you through this!
It seems like a classic case of communication mismatch. Just a guess, but it seems the PLC may be set to a different communication protocol than the DF1 you're using. The DH+ protocol on the Panelview might be interfering with communication attempts via DF1. It's definitely possible to connect to different nodes on a DH+ network, but if none of your PLCs are currently accessible via DF1, it means the PLCs might be locked in a different protocol or baud rate. I would suggest checking the communication settings on both your PLC and Panelview, resetting them if necessary, and making sure they're in sync.
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Answer: Answer: Communication loss during the download process could be due to potential disruptions in the DF1 communication protocol. It's important to troubleshoot the DF1 settings and ensure they are correctly configured.
Answer: Answer: To avoid communication loss when adjusting the DH+ address node online, make sure to carefully follow the proper sequence of steps and confirm the settings are correct. Additionally, consider checking for any conflicting configurations that might be causing the issue.
Answer: Answer: Yes, it is possible to connect to different nodes on the network via DH+ to troubleshoot and resolve communication issues. Make sure to verify the network topology, node addresses, and communication settings to ensure successful connections.
Answer: Answer: The inability to access PLCs on the network via DF1 could indicate issues with the DF1 configuration, network setup, or compatibility. Verify the DF1 settings, network connections, and PLC compatibility to address this accessibility issue.
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