How to clear a SLC-500 controller's memory and reset it to factory defaults.
In the SLC-500 family of controllers there are three different ways memory is backed up, and therefore three different ways to clear memory and reset the controller to factory defaults.
NOTE: Always upload and save any SLC-500 controller program you need prior to erasing the controller's memory.
Case 1) The SLC-5/03, 5/04, and 5/05
These three controllers have a built-in capacitor which is designed to keep the controller's memory powered for roughly thirty minutes.
This means if you simply disconnect the controller's battery, and wait over thirty minutes (actual time is based on a number of factors,) the memory on the controller will be erased.
That said, Rockwell also provides two connections on the controller board which you can short together for 60 seconds to drain the memory capacitor and clear the controller's memory.
These two connections are labeled as GND and VBB, and as shown below they're in slightly different positions depending on if you have a SLC-5/03, 5/04, or 5/05:
SLC-5/03 Memory Capacitor Connections
SLC-5/04 Memory Capacitor Connections
SLC-5/05 Memory Capacitor Connections
Case 2) The SLC-5/01 – 4K, and 5/02
This means that if you remove the controller's battery while these controllers are unpowered, the memory on the controllers will be erased.
Case 3) The SLC-5/01 – 1K, and Fixed Models
The capacitor was designed to keep these controller's memory powered for between 5 and 30 days (depending on ambient temperature.)
Rockwell also doesn't make connections available to drain these capacitors, so the only way to clear the memory on these units would be to leave them unpowered for the 5 to 30 days.
Conversely, if you can communicate to the controllers you may wish to just download a new blank program to them rather than wait for the capacitor to drain.
I hope today's article about how to reset SLC-500 controllers to factory defaults was helpful.
If you have any questions, comments, or suggestions, please feel free to post the by clicking on the “Click here to post a comment or question” link below.
Sponsor and Advertise: Get your product or service in front of our 70K followers while also supporting independent automation journalism by sponsoring or advertising with us! Learn more in our Media Guide here, or contact us using this form or by calling our office at 413-749-4300.
- PLCs: Past, Present, and Future - June 24, 2022
- How To Download Rockwell's Integrated Architecture Builder (2022) - June 23, 2022
- Rockwell Remote Access (P107) - June 22, 2022
The Automation Blog's SLC-500 Library
- Article: The SLC-500: Six Controllers
- Article: The SLC-500: Controller Image Gallery
- Article: The Fixed Style SLC-500
- Podcast: Programmable Controller Non-Volatile and Volatile Memory
Cables and Adapters
- Article: USB to Data Highway Plus using the ANC-120e, a lower cost alternative to the...
- Article: How to add Ethernet to a SLC-500
- Podcast: Adding DH-485 to your MicroLogix, SLC-5/04, SLC-5/05, and PanelView Plus 6 400 and 600.
- Article: The SLC-500: Communicate and Download over Serial DF1 using RSLinx and RSLogix 500
- Video: A-B SLC-500 Serial Comm Setup & Download
- Article: The SLC-500: Communicate and Download over DH-485 using RSLinx and RSLogix 500
- Video: A-B SLC-500 DH-485 Comm Setup & Download
- Article: PLC-5 and SLC-500: Communicate and Download over Data Highway Plus using RSLinx and RSLogix
- Article: Why the Allen-Bradley (A-B) 1747-PIC always had trouble working in Microsoft Windows
- Article: What's new in RSLogix 500, Micro v11
- Article: RSLogix 5, 500, and Micro support for Windows XP / 7 / 8
- Article: RSLogix 500 and Micro Get Windows 8 Release
- Article: How to get a free copy of RSLogix Emulate 500
- Article: How to setup and use RS Emulate
- Article: How to Message (MSG) data from a MicroLogix 1400 to a SLC-5/05 over Ethernet
- Video: How to Message (MSG) data from a MicroLogix to a SLC-500 over Ethernet
- Article: How to Message (MSG) data from a SLC-5/05 to a MicroLogix 1400 over Ethernet
- Video: How to Message (MSG) data from a SLC-500 to a MicroLogix over Ethernet
- Article: Get A-B Programmable Controller data into Microsoft Excel using RSLinx
- Article: Connecting a PanelView Plus to a SLC-500 Channel 0 Serial Port
- Video: Flashback – FactoryTalk View Importing PLC-5 & SLC-500 Tags
- Article: How To Convert SLC-500 Programs to MicroLogix
- Video: Converting SLC-500 Programs to MicroLogix
- Article: Replace a Fixed SLC-500 (1747-Lxxx) with a MicroLogix
- Article: Converting your RSLogix 500 program to RSLogix 5000 using the Translate PLC-5 SLC 2.0...
- Article: Changes I would like to see made to Rockwell's Translate PLC-5 SLC 2.0 utility
- Article: Working around the Translate PLC-5 SLC 2.0 utility’s syntax error
- Article: Flashback Friday! RSLogix 500 "Providence Beer" Demo
- Article: Flashback Friday! RSLogix 500 Top Ten Sort
Learning and Discussion: