can not change my logic

[Guest Peter]

Have SLC5/04 and a program that has been developed and tested a year ago. The same program that is running in the PLC I have on the LapTop. Using RSLogic 500. Trying to do a small modification in the logic (adding one rung) but cannot make it happen. Have no problem with editing and downloading the program into the PLC. Even after downloading I see on the laptop my rung there and doing something. However the process is still working as there is no new rung. When I upload the program from the PLC I see there is still the old program there without my new rung. Please help

[Guest 5150]

If you uploaded the code and made changes, but the changes are not apparent after you download to the 5/04, I would suspect protected memory. I have had this same experience in the past. I simply removed the 5/04 from the rack, disconnect the battery backup and short the two soldered pads VB and GND (on back side of processor board) with a screwdriver for 60 seconds. This procedure wipes the memory, but will allow you to download to the PLC your revamped code. (Make sure you reconnect the battery backup before re-inserting into the chasis. --5150

[Eddie Willers 2]

Are you sure there isn't an EEPROM plug in the SLC, which would load your new program over the old one on power cycle ?

[Guest]

the key words in your post could be: this may be all out in left field so feel free to ignore it if I’ve guessed wrong ... I’ve seen people confuse the term “download” with the term “accept rung” before ... maybe that has something to do with your problem ... basic idea: when you “download” you’re send the ENTIRE program (in other words, ALL of the rungs, new and old alike) into your processor ... basic idea: when you “accept” a rung, you’re (usually) sending only ONE rung to the processor at a time ... if you accept your new rung while the processor is in the “Run” mode, then you MUST do the next step and “test” your edits ... actually this extra “test” step tells the processor to begin executing the new rungs ... see if this helps ... and good luck ... best regards, Ron