adccommunitymod (AutomationDirect) asked a question.
Created Date: February 14,2003
Created By: Josh West
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Hi everyone, I'm new to this forum and fairly new PLC programming as well. I 've done a couple of jobs with the DL05 in stage and standard ladder, but I'm lacking in the experience area. The job I'm on now is using the DL05 with a pnp out expansion card. The problem I'm having is,,, there are two bits that I can't seem to set. Don't Laugh! The ladder is compiled and downloaded into the plc, shows no errors. I can force the bit on and see it on in status mode, but when the conditions are met the output (just a set coil) will not trigger. The conditions to be made are 1 normally open input and 1 normally closed contact,, IF X3 AND NOT C2 THEN SET C3 The other instance is similiar , but with trying to set an output. I have to missing something obvious. Is there a way I can attach the prj to this thread for you to view? Any ideas?
Created Date: February 14,2003
Created by: Josh West
Hi everyone, I'm new to this forum and fairly new PLC programming as well. I 've done a couple of jobs with the DL05 in stage and standard ladder, but I'm lacking in the experience area.
The job I'm on now is using the DL05 with a pnp out expansion card. The problem I'm having is,,,
there are two bits that I can't seem to set.
Don't Laugh!
The ladder is compiled and downloaded into the plc, shows no errors. I can force the bit on and see it on in status mode, but when the conditions are met the output (just a set coil) will not trigger. The conditions to be made are 1 normally open input and 1 normally closed contact,, IF X3 AND NOT C2 THEN SET C3
The other instance is similiar , but with trying to set an output. I have to missing something obvious. Is there a way I can attach the prj to this thread for you to view? Any ideas?
Created Date: February 14,2003
Created by: bcarlton
1. (So incredibly obvious as to be insulting so I apologize in advance) Have you removed the force override?
2. Look for any occurance of C3 between this logic and the end of the program. Don't forget any subroutines or interrupt routines. See if it may be included as part of a word operation (eg OUT VC0)
Created Date: February 16,2003
Created by: DonHill
Don't mix set/rest and outputs for the same output even if they are in different stages.
If you have it in more than one place the ladder executes from top to bottom and the last setting (set/reset) wins for that scan.
(If project is small email to f1racefan@msn.com)
Created Date: February 16,2003
Created by: tmiked
The answers above are great. I had similar problems when I was starting out. You can test bu eliminating all rungs which could possibly conflict and run the program. Add the rungs back one at a time. Having ALL commands for a specific output on the same rung is a safe way to eliminate this problem.
Hey Don ! I noticed your eamil address. I was looking last night and airfares to Australia for March 9 .... I bet you know why http://forum1.automationdirect.com/board/smile.gif
Created Date: February 17,2003
Created by: Josh West
Thanks for the responses guys. I 've tried several of them already. I'm emailing the file to Don momentarily to see what he comes up with and I'll make sure to post what the problem was.
My next step was going to be printing out the ladder,starting a new program and pasting in 1 or 2 rungs at a time. It sure would be nice to be able to temporarily disable a rung, kind of like commenting it out in vb/vc, ect.
Created Date: February 17,2003
Created by: tmiked
You can 'comment out ' a line by putting in an extra open contact. This works for longer programs where rebuilding a line at a time is too tedious
Created Date: February 17,2003
Created by: Josh West
I thought about that, but it's not quite the same. The rung still gets compiled. I'm beginning to wonder if I'm doing something the plc doesn't like even though it's not throwing an error.
The program is pretty straight forward and simple, but it's not exactly the most favored way to do things. I wasn't involved in this project until the damage was already done. I was just told to order a "cheap " plc with a couple of inputs and outputs. Now the thing has grown exponentially and I neither have enough I/O or the approval for a DL205. I just have to magically make it work. So the end result is that I'm using the state of several of the outputs as arguments in rungs. Instead of using an input with a sensor to verify the location of a cylinder, I'm looking to see if the output for a specific solenoid valve is on, and "assuming " there is air pressure and the cylinder is really in position. I'm beginning to wonder if it has an issue with adding contacts labeled Y3, ect.
Created Date: February 17,2003
Created by: Josh West
Nevermind, I figured it out guys. It was an error in the ladder that wasn't throwing an alarm when compiled. Something just plain dumb. I was trying to use an out coil to trigger an input from the ladder in place of an external button,, to simulate the button press. It wasn't relavent to the rung I was looking at, but it stopped everything. Thanks for your help.