I added two new ladder rungs 8&9 and added a new chassis rack 5. I downloaded my new additions to the proccessor plc5/40 enhanced and I cannot get the two new ladders to work. The coils and timers will not operate. I have two input cards and two output cards with a adaptor 1771ASB I can force the coils and they show on the output card and can jump the inputs and they read on the program and cards. It acts like the proccessor is not scanning the new ladders.I'm a rookie programmer and have never added ladders to a rack before I must be missing something could use some help.
Thanks,
Tom

 

"It acts like the proccessor is not scanning the new ladders"

It probably is not scanning. Look in your first ladder for JSR instructions referencing all other ladder files. The JSR (Jump subroutine) is required because the AB PLC does not automatically scan all ladders, just the main. If you add JSR referencing your new Ladders, the PLC will then scan them and you should be in better shape.


-BDS

 

Tom,

Just to clarify, did you add new rungs to an existing ladder or new ladder files? Because if you added new ladder files you will also need JSR instructions in ladder 2 before the new ones are scanned.

 

If you added the ladder to a new programming file, make sure the new file is being scanned. You would need to add a JSR (Jump to Subroutine) instruction to each file to have it scanned.

also...
Make sure the PLC is in RUN mode.

-mjv

 

Tom,

You must add a JSR os jump to subroutine in your main ladder #2. this will tell your program when and in what order to scan your new ladders
ED

 

Are you sure ladder is scanning? Check the MCP tab to see if that LAD file is on scan or make sure there is a JSR for that Ladder file. Good luck!

Michael E. Crossman
PLCs Plus International, Inc.

 

Did you add two new rungs or two new ladder files? If you added files, they must be called like a subroutine from the MAIN ladder file or some other file which is already being called.

Is the processor in run mode (presumably so, if outputs can be forced)? Are the new rungs assembled or at least in test? Is there a JMP or other program flow or rung-power control instruction not allowing the rungs to operate?

 

You must add (in the main ladder) JSR instruction, this instruction Jump to the SubRoutine that you like.

Goog Look

 

Did you reconfigure your PLC to recogonize the new ASB and IO cards?

Sekar

 

Did you add the JSR U:8 AND JSR U:9 to the main ladder?

JSR 8 0

JSR 9 0

copy each one to a new line in the main

 

And you've added in the JSR instructions for these two new ladders in LAD2? (Apologies if patronising! - Have to check these things)

 

Tom

It sounds like you need to add some JSRs or jump to subroutines. In rslogic5 go to the help menu and select PLC5 instruction help, then select JSR. This will tell you more than you want to know. While here look at all the lovely instructions you can use, I try to pick a new one from time to time and try it out. Good luck

Ward

 

Hi Tom

I am not surewhat you have done and what you have done but by the sounds the rack is configured right as you are able to force the outputs

if you have done the ladder in a new file then in your main file you have to add a jump sub routine function (JSR) so the processor will scan the new ladder you have created in the jsr you must put the file number eg. U:3
hope this helps
cheers

Andrew

> I added two new ladder rungs 8&9 and added a new chassis rack 5. I downloaded my new additions to the proccessor plc5/40 enhanced and I cannot get the two new ladders to work. The coils and timers will not operate. I have two input cards and two output cards with a adaptor 1771ASB I can force the coils and they show on the output card and can jump the inputs and they read on the program and cards. It acts like the proccessor is not scanning the new ladders.I'm a rookie programmer and have never added ladders to a rack before I must be missing something could use some help.
> Thanks,
> Tom

 

Did you put a JSR instruction in your MAIN routine. I suppose that you have to add a JSR 8 (for LAD 8) and JSR 9 (for LAD 9) instructions in your LAD 2 (MAIN)
Hope this helps

 

What file did you add the rungs to?
What type of coil is rung 7? If it is an END coil it will jump over the rungs you added and go to the next file that is called

 

Perhaps there's an MCR or JMP before the rungs you added that's bypassing them.

 

If you added the rungs to the main ladder file(ladder 2) and you put them after the "end" instruction, they will not be scanned. You have to delete the end rung and reinsert it at the new end fo your ladder. If you added the new rungs as a new file (ladder 3) you will need the "jsr" instruction in ladder 2. You can find all the manuals you need at the AB site.