ETJ

Cool.. do you mind sharing some of the code of what you have done? Like, how you assign the sequence, change the sequence, changing the limit statements etc..? Thanks.

Yeah.. Thats great.. I like to have the ability to view/know what current step my plc is running just incase i need to troubleshoot it. I also like to have the ability to control which part of the program that is able to run based on the "Stage Counter" N7:0. That will help to seperate out the program into stages. Another thing I like about that is to have the ability to plan the whole process in a sequential kind of way. That way, based on the "Stage Counter" I can know what stage/process will happen next. I know that another common way of programming is by setting/resetting the latch, but I prefer the "Stage Counter" way because it is able to "kill 3 birtds in 1 stone". Having said that, I think that it also has its own limitations. For a large complex project where there are hundreds of different stations/processors, you will need the equal amount of "Stage Counters" because no 2 stations/processors can share the same "Stage Counters". So if each "Stage Counters" uses 1 integer then 100 "Stage Counters" use 100 integers. I'm do not know if a typical PLC has that muuch memory.. Anyway, since i'm quite new to this kind of programming, please do share more of your experiences. The pros and cons of it. Thanks.

Hi all, I was just playing with different concept of ladder programming and I would like to know what do you guys think about it. The programming is divided into 2 sections which are: 1) Stage transition and stage dependent output/action - Transition from what stage to what stage when a certain input is triggered as well as what will happen to a stage dependent output/action. (Rung 1 - 4) 2) Output dependent - what will happen to a certain multistage/"stage independent" output. (Rung 7 - 9) I just thought about it yesterday so I decided to do a simple programming using Logixpro Door (Exercise 4) and post it up for some feedback. Please do share your thoughts about it. Attached below are the .rsl files and .bmp of the sequence. Thanks. Door_Stage based.rsl

Hi, I'm trying to implement state machine in PLC. Need some advice on it Attached is some code on State Transition. Assuming that the instruction "JP 31" has been called, the code will now jump to "LBL 31" which is the beginning of my state transition code. "JP 32" to "JP 37" are used to jump to my states (State 32 to 37) when certain conditions are met. "DT 99" is the data register (Program Counter) where I store my current completed state number. Lets say i'm now at state 33 ("LBL 33" and "DT 99" = 32) and i've done what I needed to do there and am ready to transit to next state, what I'll do is in "LBL 33", i'll increase my Program Counter "DT 99" to 33 and after that jump back to "LBL 31". It will then 'hang' at rung 180 until T1 is HIGH. After that, it will jump/transit to state 34. This is the concept that I have. However, my PLC will only arrive next week so I am not able to test whether it work or not. Can somebody advice whether the code will work or not.. Will the instruction at rung 229 be executed since at rung 226, i've commanded it to jump back to "LBL 31". Pls advice ya.. Thanks. State Transition.doc

Hi.. Sorry to bump this dinosaur post, but i need advice related to this post. I'm using a Mycom stepper motor driver (IMS500-120L) with FX1N-40MT. On the motor driver, I connect the following CW+ - 24V with current limiting resistor CCW+ - 24V with current limiting resistor CO+ - 24V with current limiting resistor However, I'm not sure how to connect the driver (CW-, CCW-, CO-) to the PLC Y0, Y1 etc.. Attached is the datasheet for the motor driver. Can somebody please advice me on this. Thanks. MyCom_Driver___5PH21.pdf

I did that to learn PLC programming as I plan to change my career path. I was an application developer involved in Wonderware InTouch and .NET and stuff. Because my background is E & E, I plan to jump into Automation so I learn PLC programming.

Hi.. I've just completed Exercise 2 of Traffic Light simulation (using WordCompare). The one about Walk sign showing and blinking. Please comment/critic/advice. Thanks heaps.. Exercise_2.zip

Thanks paul for the indepth writeup.. Read it once but will definitely read it again when I have more time to enable me to digest it more.. Thanks again..

Thanks... I don't quite get what you mean by that or how to do it.. Can you please give me some example..? Thanks..

yay.. thanks.. I was abit worried when coding it because i 'wasted' 4 rungs. I could have saved 4 rungs if i'd connect the output directly to the input for run light, motor, valve and filling light. If I remembered correctly, the logixpro student exercise said not to use too many rungs for the program.. I also came across some program using fewer rungs but look more 'professional'.. But then again... I was trying to think in terms of maintenance and easy modification.. Hmm.. newbie's insecurities I guess..... Btw, is there any right method to planning and programming apart from writing comments..? I was thinking since I've jst started learning plc programming, might as well as do it the right way from the start.. hmm... Thanks again..

Hi.. I'm new to plc.. I've just completed the Silo simulation exercise 3. I know it has alot of rungs because my initial idea is to activate output by using state/flag instead of input. This is so that it is easier to modify the coding later on if needed to. But i'm not sure whether it is necessary to do so or not.. Can somebody please comment/advice/critic..? Thanks..