PLC Program Issue (Basic? Maybe Stupid)

kevilay

Member
Join Date
Feb 2009
Location
Ontario
Posts
174
Hey guys I was just making a basic program for some game thing I was tryin out. I havent writ a plc program in probally a year so Im a little rusty. I was never that great to start haha. This is a basic program all it is is one master timer that counts to 2000seconds. It is triggered by a PB input. This pushbutton is held down which is why it doesnt latch in the program. Then i am using a greater then and less then function to compare times to the T4:acc and turn on an output accordingly, but my comparators arnt activating. Im using micrologix 1000

Here is a rough sketch:


----Input1--------------------------------------Timer4:0----
Greater Then T4:acc 1---- less then t4:acc 3--- output 1


I know this is rough which is why I have a picture attached. Its just the start, but the whole program is probably 10 compares then I have a reset at the end. Oh btw all the hardware is correct. None of the rungs light up green in the program.

http://yfrog.com/15gtdonep

Thanks Kevin


Edit: I forgot to mention everything seems to count properly. T4:acc will read 2, My greater then will read the 2 but still does not light up.
 
Last edited:
Post your .rss file ( zip it first ) and someone will take a look.

If you can't post the file then tell us the time base of the timer.
Are you looking at your PC's RSlogix's screen to monitor the output or are you watching the output light on the processor.
Its quite possible your PC's monitor is not updating fast enough.
 
Last edited:
You have output O:0/0 addressed in three different rungs. Only the last rung in the program will have any effect.

Are you wanting to turn on three different outputs, for example, output 1 at 1 < timer < 3, output 2 at 1200 < timer < 1202, and output 3 at 1205 < timer < 1207? If so then correct the output addresses.

Or are trying to turn on the same output at three different times? If so then program just one run with one output instruction and put the different comparisons in branches.

Also, for you consideration, you might take a look at the LIM instruction.
 
If you use Lim, with the same Low Lim value as High Lim Value I think that the EQU would be better.
I suggest that you put your values in Integer files rather than constants. That way you can change them on the fly.

BranchedCompares.jpg
 
Could you clearly define the deliverable objective ? This will save us the time of trying to guess what it is that you want to achieve with your app.

Bob A.
 
Hey guys thanks for all the responses. I think my mistake is using the same output on different rungs. Im gonna to fix that and use limits and put it on the same rung. Then Ill get back to you with my results.

Thanks
Kevin
 

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