Subject: Troubleshooting SLC 5/05 PLC Communication Issues After Program Download Hello everyone, I'm currently troubleshooting an SLC 5/05 PLC that intermittently experiences faults when a new program is uploaded. I've already replaced the battery, but unfortunately, that hasn't resolved the issue. This problem has occurred several times in the past, and my usual approach involves removing the CPU, taking out the battery, shorting the capacitor, and then trying to download the program again. Sadly, this method hasn’t worked this time. At present, I’m seeing a blinking fault light and a steady green Ethernet (ENET) indicator, but the CPU remains unresponsive to ping commands. When I accessed the DHCP-BOOTP Server, I noticed it was receiving requests, so I assigned an IP address, which allowed it to respond to ping successfully. This gave me hope that I could now download the program. However, every attempt to perform the download results in RSLinx 500 displaying "communications errors" and preventing the PLC from receiving the program. It's also worth mentioning that I’m unable to disable the BOOTP/DHCP functionality in the Server; my attempts result in a "Connection refused" message. I would appreciate any insights or suggestions on how to resolve this CPU's connectivity and communication issues. Thank you!
- Attempting to download using a serial cable with the DF1 driver? Consider resetting the processor by removing the battery and briefly connecting the GND and VBB terminals for approximately 60 seconds. Additionally, make sure to update the firmware for optimal performance.
Quick Update: After conducting extensive Google searches and reviewing related articles, I’ve gathered the following insights: The command "arp -a" confirms that the PLC's MAC address is accurate. However, entering the CPU's IP address into a web browser yields no response, and I can't access any diagnostics. Additionally, I've encountered a recurring "not responding" error with RSLogix whenever it attempts to transfer the executable. This error is followed by a message indicating that the download has failed. I'm uncertain whether these issues are interconnected or not.
User **harryting** inquired: “Have you attempted downloading via a serial cable using the DF1 driver?” Click to expand... I haven’t tried that yet; there is a DF1 connection on the CPU, but I'm uncertain where it leads. I don't have the necessary equipment on hand, but I’ll investigate what the connection interfaces with. Additionally, it's worth considering a processor reset by removing the battery and briefly bridging the GND and VBB contacts for approximately 60 seconds. Click to expand... I’ve attempted that several times, but not for the full 60 seconds—should I retry the reset for that duration? My previous attempts lasted around 20-30 seconds. – Regarding firmware updates, would that make a difference even if the CPU was operational earlier today and I was able to work on it without issues? If a firmware update is recommended, could you please provide me with detailed instructions? Thank you!
If you're looking for a 60-second reset solution, you might find valuable insights in various discussions here. It’s worth giving it a shot! I recommend starting with a serial download; for this, you'll need a standard null-modem cable along with a USB-Serial adapter if your PC lacks a dedicated serial port. Regarding firmware updates, the 5/05 firmware can only be purchased from Rockwell, and it includes both the firmware and installation instructions. I previously went through this process with an older 5/05 unit to unlock some new features. Many discussions suggest that updating the firmware is a viable option to enhance system stability. In your situation, I would advise trying the serial connection first.
User "harryting" mentioned that a 60-second reset has been suggested in various threads. It seems worth a try. Click here to read more. However, I attempted this method, and unfortunately, it didn't yield any results. I recommend starting with the serial download option. To do this, you'll need a standard null-modem cable along with a USB-to-serial adapter if your computer lacks a traditional serial port. Click here for further details. I have the necessary hardware, but I'm uncertain about how to establish the connection. Should I access RSLinx to set up a DF1 master and proceed from there?
It sounds like you're dealing with a frustrating situation! Have you checked the Ethernet cable and ports for any physical damage or loose connections? Sometimes it can be something as simple as a faulty cable or a port issue that disrupts communication. Also, double-check the firewall settings on your PC or network that might be blocking RSLinx from communicating effectively. If you've got access to another PC or laptop, it might be worth trying to connect from there to rule out any software or settings issues on your current setup. Good luck, and I hope you find a solution soon!
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