1. 14298 - Restoring Factory Defaults to SLC-500 Processors
How can I restore a SLC-500 processor back to Factory Defaults?
( The Ladder Program will be lost if a processor is returned to Factory Defaults )
If the ladder program must be saved / recovered from the SLC Processor
please see KnowBase Document 16846
Note: If a memory module, that has been configured for autoload is installed, after performing a
reset. The old program will be restored into the processor RAM memory.
SLC 500 Fixed I/O
1.Remove Power
2.Open CPU Compartment ( Series C units can not be factory reset )
3.Disconnect Battery
4.Remove Memory Module ( 1747-M1 ) Skip step 4 if a Memory Module is not Installed
5.Locate RAM (IC3)
6.Connect Pins 14 and 28 (PWR & GND) with paper clip.
See Diagram on the following page
( NOTE: The preferred connection method is to use a 10 Ohm Resistor )
Short for 20 Seconds or More

2. SLC 500 ( 5/01 & 5/02 )
1.Remove Power
2.Remove CPU Module
3.Remove Memory Module ( EEPROM )- 1747-M1
( Skip step 3 if a Memory Module is not Installed )
4.Disconnect Battery
5.Locate RAM (IC3)
6.Connect Pins 14 and 28 (PWR & GND) with paper clip.
( NOTE: The preferred connection method is to use a 10 Ohm Resistor )
Short for 20 Seconds or More
SLC 500 ( 5/03, 5/04 & 5/05 )
IMPORTANT: Jumper J4 on the processor must be set to the PROTECT position.
(NOTE: Jumper J4 is used to Protect the Processor Firmware, and is not related to the Ladder
Application)
1. Remove Power
2. Remove CPU Module

3. 3. Remove Memory Module ( 1747-M11 ) Skip step 3 if a Memory Module is not Installed
4. Disconnect Battery
5. Locate the GND & VBB points on the back side of the processor module.
6. Using a small flat blade screw driver short the GND & VBB points for 60 Seconds.
(Take care to make a good metal-to-metal connection)
IMPORTANT:
Once Factory Defaults have been restored the ladder logic program will be lost and all
communications channels will be reset to their default state, See Below:
SLC-5/04 CH1 - DH+ ( 57.6k baud )
SLC-5/03 CH1 - DH485 ( 19.2k baud )
SLC-5/05 CH0 - DF1 Full Duplex 19.2k Baud, N, 8, 1, CRC
SLC-5/04 CH0 - DF1 Full Duplex 1200 Baud, N, 8, 1, CRC
SLC-5/03 CH0 - DF1 Full Duplex 1200 Baud, N, 8, 1, CRC
Note: SLC 5/03 OS302 FRN 11 , SLC 5/04 OS401 FRN 8 or greater Channel 0 Defaults to
19.2KBaud
Reference(s):
16846- Lost or Forgotten passwords procedure for the Micrologix, SLC-500, PLC-5 Family of
controllers and RSLogix software. Processor is prompting for a password and password is either
lost or forgotten.