If you've reset your controller to its default settings, consider manually configuring RSLinx. Use the following communication parameters for optimal setup: DF1 Full Duplex, baud rate of 19.2 KBaud, with N for parity, 8 data bits, 1 stop bit, and CRC (these are the default settings).
Would you like me to explain the manual setup process for RSLinx? Thank you!
How to Configure an RS-232 Serial Driver for Allen Bradley and Connect It to an SLC-500 PLC
Looking to set up an RS-232 serial driver for your Allen Bradley equipment and establish a connection with an SLC-500 programmable logic controller? This comprehensive guide provides step-by-step instructions and essential tips. For a visual reference, check out this informative video: https://youtu.be/KHBrE0xKSWs.
Thank you, Tarik. I've already tried all initial troubleshooting steps, including deleting the configured driver and reconnecting it. Unfortunately, I'm still encountering the same issue where auto-configuration fails, and the driver does not appear in RSLinx Classic.
User Rehu09 inquired: Would you like me to explain the process of setting up RSLINX manually? I appreciate it! To view more, click to expand... In the same window where the auto-configure option is available, you can manually choose the default settings. Please refer to the accompanying image for guidance.
I've completed this task, Mickey, but it still isn't displaying correctly.
User Rehu09 commented: "I noticed a steady red fault light on the processor after turning on the PLC. Given that it hasn't been used for an extended period, I suspect it may have lost its program and IP address. If your PLC displays a continuous red fault light, it typically indicates a malfunction. The only viable solution is to attempt shorting the VBB and GND, as Mickey suggested. In this scenario, the fault light should start flashing. If the device simply lost its program, the red light would blink; however, a malfunctioning PLC will show a solid red."
- 08-05-2025
- geniusintraining
How can you determine if the memory has been successfully cleared from your processor? Here’s how to check and ensure that memory clearing was effective.
After following Mickey's advice to clear the memory, I installed my processor into the slot, but the fault indicator began blinking again. Eventually, it turned solid red, which is quite concerning. I'm wondering what options are available for replacing the processor. My colleague mentioned that since it’s a brand new PLC, I should be able to download the program once it shows a solid red fault. However, it’s not appearing in RSLinx. How can I resolve this issue and successfully download the program?
My colleague has pointed out that when the Fault (FLT) LED on the brand new PLC illuminates solid red, it indicates a "hard fault." This means that the controller is unable to communicate and cannot be reset. Conversely, if the Fault (FLT) LED is flashing red, it signifies that the controller has encountered an error but is still prepared for a new program download. Should the LED remain solid red after several power cycle attempts, it is crucial to replace the controller. For troubleshooting PLC faults, understanding the LED indicators is essential for effective maintenance and repair.
User Rehu09 reported a concern: After installing my processor into the slot, the fault light began to blink and eventually turned solid red. This situation has me quite worried. What options do I have for replacing the processor?
Expanding on Ken's observation, the lights on the PLC function similarly to a computer's startup sequence, indicating that various processes need to be initialized. Typically, the last components to boot up are the daughter board and memory. When the CPU starts flashing and subsequently fails, it’s often an indication that the daughter board is the culprit, based on my experience.
That being said, few individuals possess the skills required to repair it, so I recommend considering a replacement. If you'd like us to take a look at it, we can do so at no cost beyond shipping fees. Feel free to email me or send a private message. Additionally, remember to hold the short on the VBB and GND for 30 seconds to ensure proper function.
- 08-05-2025
- geniusintraining
Ken Roach explained that when the Fault (FLT) LED is flashing red, it indicates that the controller has encountered a fault but is still prepared to receive a new program download. However, if the Fault (FLT) LED is solid red, the controller is in a "hard faulted" state, preventing any communication. If the LED remains solid red after several power cycles, it is necessary to replace the controller.
During a discussion with a colleague, he mentioned that it is typical for a default PLC to maintain online communication under normal circumstances. I felt pressured, as he seemed eager to find an opportunity to challenge my approach. I informed him that I had utilized a 1747-CP3 cable for communication. He inquired if that was a serial cable or a null modem cable, and suggested I consult the manual, assuring me that it would guide me through establishing an online connection.
He emphasized that when you purchase a new processor, its default state will show a solid red fault light, and it's crucial to verify this. I share his concern.
User Rehu09 explained: "I had a conversation with my colleague regarding the default behavior of the PLC. He mentioned that there's no reason why you shouldn't be able to connect online. I'm currently feeling pressured; he is always searching for an opportunity to capitalize on situations like this. I wasn’t sure how to proceed, but I told him that I used a 1747-CP3 cable for communication. He inquired if that was a serial cable or a null modem cable. He suggested I check the manual, insisting that it would guide me through the online setup with certainty. He pointed out that when you purchase a new processor, it typically indicates a 'default' state with a solid red fault light. It's essential to verify this. My concern is growing."
[For more details, click to download the PDF that explains indicator meanings.]
Mickey mentioned: "Refer to the PDF for the meaning of the indicators." Click to expand for more details. Thank you, Mickey! I plan to revisit this topic with him. However, I’m curious about his strong confidence in getting the processor up and running again. I’ll follow up with him tomorrow and keep everyone updated. Thanks to all for your valuable support!
While it may seem unlikely, consider testing it with a reliable power supply before deciding to abandon it. This step could help identify the issue more accurately.
Rehu09 expressed gratitude, saying, "Thank you, Mickey. I plan to revisit this topic with him soon. However, I’m puzzled by his strong assurance in bringing the processor back online. I’ll follow up with him tomorrow and provide everyone with an update. I appreciate all your support!"
As for the next steps, let’s see if he can deliver on his promises—time to either prove his claims or step aside.
OkiePC suggested: "While it's a bit of a gamble, consider testing it with a reliable power supply before deciding to abandon it." To elaborate, I have already connected the 120V to the power supply. Could you please provide more details about this, OkiePC?
Rehu09 stated: "I've hooked up the 120V to the power supply. Could you please provide some clarification on this, okiePC?" Click to expand... It seems that the recommendation is to replace the power supply unit (PSU) itself, as certain issues may arise from a faulty power source.
Mickey mentioned that it's essential to replace the power supply unit, as it can lead to unusual issues. I’ll use a multimeter to measure the input voltage for validation. If that doesn't resolve the issue, I will remove the processor and install it in a different slot for further testing. Thank you for your guidance, Mickey!
User Rehu09 commented: "Alright, Mickey, I'll measure the input voltage with a multimeter to confirm it. Thank you, Mickey!" Click to expand... "Please make sure to check the voltage directly on the power supply unit itself, not just the input. If you have a backup unit available, that would be helpful. For further details, check this link: http://docs-europe.electrocomponents.com/webdocs/0dfa/0900766b80dfaff9.pdf."
Rehu09 mentioned: "Otherwise, I'll take out the processor and install it in a different slot to check its functionality." Thank you, Mickey. Please clarify what you meant, as the processor is designed to fit solely into the primary slot.
Mickey suggests that you consider using a different power supply, which is the device to which your power cable is connected. On the left side of the rack, you’ll find a grey box; this is the removable power supply. Power supplies can sometimes fail, and while they may still provide power to the rack, they can lead to unusual issues, including faults in processors. Although it's a long shot, given the investment in an SLC5/05, it’s worth testing with another power supply if you have one available. If you have access to another rack, try placing your SLC5/05 in that unit (ensuring the key switch is set to program mode) to check if the fault LED blinks rather than stays solid. If the fault LED remains lit when you insert the processor into a different rack or use an alternative power supply, it indicates that the processor itself is likely defective.