automate 20

I have a reliance automate 20 and trying to run APX programming software. I have established comm, but when i try to load a program into the processor, I get "KEYSWITCH OR SYSTEM LOCK" error. What is my problem?

I don't know anything about the Automax 20, but from the text of the error message I'd be looking for a keyswitch on the CPU module. If not that, check the manual for some other method of protecting the memory from change.

There should be a three position keyswitch. You must switch to "Program" to load the program into the processor. See page 12 of this manual.
http://www.dodge-reliance.com/pdf/catalog/custom_classic/automate.pdf

If you dont have a key for the keyswitch, I believe a very small screwdriver could be used with care to turn it. If that doesn't work, perhaps you could mark and remove the wires, then, with a little luck, you could connect the right wires to bypass the switch function.

Copied from pg. 12:
THREE POSITION KEYSWITCH
- RUN – The program or status cannot be modified.
- PROGRAM – The program and status can be changed.
Variable data can be modified.
- SETUP – The program or status cannot be changed. Variable data can be modified.

I may have been mistaken about a keyswitch on that particular model. If it doesn't have a keyswitch, try putting the processor in "Stop" mode, choice 2 in the APX software menu, before downloading your program. After downloading, put the processor back in "Run" mode, choice 1 in the APX software menu.

Before you can download a program to the PLC, dont forget to "Load" your program into the computer software, choice 7, then choice 1, then type in the name of the program, without the extension, press Enter. Next to verify that you have the program loaded into the computer by pressing Esc. back to main menu, then choice 8 Print, then choice 4 CRT, then, choice 1 Ladders, press Enter. Scroll thru the ladder.

Thanks for the reply. There is no keyswitch on the model 20. I have three processors, only one (p/n 45C220A) allowed me to load the application, and it runs fine. The other two(p/n 45C220A, 45C220B), give me the "keyswitch or system lock" errors when I issue a Stop, Program, Monitor, etc. command. Is there a jumper plug that should be installed on any of the I/O connectors to get past this? Also, it appears that the CPU Ready light is out now. When I started, the lights were on.

I dont know of a jumper plug. I will read what manuals I have to see what I can find. Here's something you can try. Open the APX software. From the Main menu, Select "A" (Auxillary Functions), then, Select "8" (Request Privilege Access) or "9" (Cancel Privilege Access). You must be Online for these choices. I really dont know which choice to use, try them both. I no longer have a processor to try this on. It's been many years ago, sorry. With the CPU Ready light off you may just have a hardware failure or end-of-life problem, might be related to the internal Power Supply, or Firmware corruption.

Copied from the manual:

CPU READY - Processor is working properly within limits of internal error detector.

I tried the privilege access commands, with the same result. I also have a manual, but I could find no reference to this error. The biggest problem is finding someone familiar with this system that is still around. The two Rockwell reps that I spoke to were of little help due to lack of familiarity. If the firmware is corrupted, do you know of any way to reload it?
I also have some third party APS software. Maybe that will work if this lockout is APX related.

Here's a link that might have some manuals or other help:
http://www.automation-consulting.com/aps/aps.htmhttp://www.automation-consulting.com/aps/aps.htm#updater

The firmware guess in the other post was mostly speculation of a failed CMOS internal chip. I dont know of a way to fix it.