Internet PLC Forum

Hello all,

Gary has provided me with a detailed reply, which explains the many fundamental issues with my program. I now understand these issues, so will not be requiring any further help.


Thanks very much,

Jordan

Gary,

Thanks very much for your reply - I have sent an e-mail to the address in your profile.


For anyone else who may be willing to give some advice, I have now attached the program file. (Hopefully it works this time).

There are likely to be many things that I've done incorrectly, although an obvious mistake may be circuit 3. I have used a rising edge trigger to initiate the first sequence, but even though there is a rising edge, could this mean that  SEQ 1:13 is being energized at all times?

Please note: The reason I have put circuits 12 to 28 into a sequence is so that the machine will still deliver a drink if the water level becomes low midway through the drink being poured.  


If anybody could recommend how I could achieve the same functionality, but written in the correct manor that would be great.


Thanks,

Jordan

Hello all,

I'm hoping that somebody may be able to help me.

I am in my final year of a mechanical engineering degree, and have a module in Control Technology.  I have llittle to no experience in regards to programmable logic, and what I know about i-Trilogi has been learned in the past 5 weeks (From class hand-outs and internet tutorials). As part of the module, I have been asked to write a program for a drinks vending machine. I believe I have given it a reasonable go, although I've having issues when simulating (I believe sometime I'm doing must be fundamentally incorrect).

When I simulate the program, sometimes relays are latching, sometimes they are not. Similarly sometimes the correct message is being displayed (In the View panel), other times the Custom functions are not working. (Even though nothing has changed).

I'm hoping somebody would be kind enough to have a look at the program. (I've used sequencers to split it up, which has writing it a little easier).

If for example the following is undertaken when in 'Simulate mode'

Manually latch Inputs, 9, 23, 56 and 99. Then press Input 7.. Then press Input 75.

I have then used a custom function to count £1.20 credit, depending on what coins are sensed. Once this is complete it goes to next sequence steps, and things start to go a little wrong:

Press any drink (Inputs 1 - 5), then if applicable choose 'yes milk' or 'no milk' then 'Yes Sugar' or 'No Sugar'. Sometimes the relevant relays latch.. which then allows the correct message to be displayed in the next sequence, and other times they do not.

Similarly if I press input 18, the program is temperamental in regards to unlatching all of the necessary relays.  When I click simulate I get many error messages saying "Seq 1 already energized" (My lecturer has told me that this is normal, but I assume this isn't supposed to happen if things are done correctly?).

My lecturer has reviewed the code, and can't find any issues. He's told me that there are software glitches - Again I very much doubt this is the case?

I anyone could  give me some advice on any of the above it would be much appreciated.

Thanks very much,

Jordan

PS -I am running the recommended version of Java.