Control Logix Guru's need your Insight

[dbh6]

@ Brendan, say on rung 1 when from the HMI the momentary PB is pressed it turns on the PB_Run_HMI bit then in the same rung another bit PB_Run is turned on and also the PB_Run_HMI is unlatched. Mind you the PB_Run is going to be on up until the next scan that it will go off, but before that first scan is over that PB_Run bit will latch on the LT_Run bit so on the next scan when the PB_Run goes off the LT_Run is on

So i also modified the routine such that i got rid of rungs 123 and just directly linked the HMI momentary pb's to the PB_run, PB_Standby etc with having any unlatch bit for them, because technically the momentary pb unlatches itself, and still the issue is still present

after that didn't work i add the unlatch bits for PB_Run, PB_Standby, and PB_Off at the end of the routine and still the same issue.

 

[DennisCotten]

Make it a maintained pushbutton. Then when you press the button it will latch, have this latch start a timer of 2 seconds. Once the timer is done have the .dn unlatch the pushbutton. That will give the button a long enough time for the PLC to see the signal, and will unlatch it after 2 seconds and make it ready for use again. Has to be done for each individual pushbutton.

 

[OkiePC]

There are about 17 different ways to deal with stuck button syndrome (which appears to be the case here).

My favorite is the good ole timer method. I want my button bit box to stay 'hot' for 1/2 second no matter how short or how long the button press really was. I wanna see that dog gone instruction turn green for a split second too.

SLC Example, same principles apply in Logix5k:

 

[dbh6]

@ dennis i tried what you insisted where i placed the rung that would start the 2sec timers based on the maintained pb's then execute the pump logic then after that i had the done bits from each time unlatch the PB from HMI, the results well it seems like its missing it more often

 

[dbh6]

@ Okie Pc if it really is a button stick syndrome i will give your method a shot, but one thing, on rung 0 you are unlatching the pb and starting a timer for 0.5 secs then you are using the timer timing bit to initiate the "do stuff" bit, when the next scan comes around your timer won't even see 0.5 secs because the unlatch wrote a 0 to the HMI_Pb1 bit, unless we are using a mainted pb from the HMI. Is that what you had in mind or am i completely wrong here?? They are closing down over here and about to kick me out so i will give it a shot tomorrow and let you guys know if anything changes till then keep the info's coming greatly appreciate the feedback.

such a simple problem, can turn into a real issue, plc i tell ya lol

 

[Bit_Bucket_07]

Wish that I could look at your program, but I don't have Logix5000 on this computer. Are other momentary HMI pushbuttons working properly? Do you execute the Pump subroutine on every sweep?

 

[Ron Beaufort]

just as a wild guess, try turning off all of that "rotation" logic for your HMI animation ... see if that speeds up your HMI's communication - and makes the button presses more reliable ...

I haven't had time to look at ALL of your program - but that extra "animation" logic just sort of looks fishy ... (we don't normally write the logic inside the PLC that way - and send it over the network to an HMI) ...

DISCLAIMER: I haven't had time to dig through your logic ... feel free to ignore this post ...

 

[dbh6]

@ bit buckets all the other pumps have the same issue and yes Iam calling the pump subroutine on every scan if that's what you meant by sweep,
@ Ron I'm using that rotation but to animate a fan and make it rotate on the HMi but I will try what you said and see if that help, I will let you guys know tomorrow because I got kicked out right now

 

[Ron Beaufort]

usually we do that type of "animation" logic in the HMI with a "derived tag" or something along those lines ... if you're doing it in the PLC then the constantly changing values might be contributing to a network overload ... could the extra network traffic be contributing to the flakey operation of your HMI buttons? ...

again – just a guess – but it wouldn't take much to try it out ...

also – on another tangent ... why do you have that one single Structured Text routine? ... it looks like a "temporary" file – for use later – but consider this: if you make use of Structured Text then anyone who follows along in your footsteps will be required to have the Structured Text option loaded on their RSLogix5000 software installation – and they'll have to know more than just "plain vanilla" ladder logic in order to troubleshoot the program that you're writing ...

sometimes that's a "good" thing - but sometimes it just adds needless extra time and confusion to a project ...

my personal opinion: if you have a GOOD reason to use STX then by all means use it ... if it's just to add a "bells and whistles" effect to the code, then I'd consider leaving it out ...

 

[dmargineau]

The ladder logic looks pretty "original"...I still wonder if it's not related to communications timing...RSView is legacy and using RSLinx to connect to a 1756-ENBT CLX bridge located who knows where on the LAN...I have never personally attempted to use RSView on a Logix platform, only FactoryTalk View and Wonderware (with an EtherNet/IP driver).

 

[dbh6]

@Ron I made a structured text routine for use later when mapping IO and just for mapping and maybe setting presets, that way I can test out my logic with the already existing assigned tags, then when I later have all my local inputs and outputs as well as other IO I will map everything, instead of going into each routine and changing the already existing tags to the IO tags.

But despite what you said I will still omit it out to see if it maybe be can make a difference

 

[Ron Beaufort]

sorry – you've misunderstood my point ...

I'm QUITE certain that the STX routine has ZERO to do with your current "HMI button" problem ... I just mentioned it as something to think about ...

my point was that anything that you're planning to do in structured text – could also be done in plain vanilla ladder logic ...

 

[dbh6]

@ron ok sorry for misunderstanding

 

[OkiePC]

@ Okie Pc if it really is a button stick syndrome i will give your method a shot, but one thing, on rung 0 you are unlatching the pb and starting a timer for 0.5 secs then you are using the timer timing bit to initiate the "do stuff" bit, when the next scan comes around your timer won't even see 0.5 secs because the unlatch wrote a 0 to the HMI_Pb1 bit

Look at the branch with the TT bit, it will be true for 1/2 second, always and only 1/2 second. It becomes my trusted internal pushbutton I use to do stuff elsewhere in the code. On that branch, it keeps the timer going.

As for the structured text routine, I think others with a standard license can open the project, just not see the contents of that file. We have standard licenses and recently received some OEM code with a FBD task. It shows up in the tree, and we can look at everything else...just not inside that solitary FBD.

 

[Ron Beaufort]

As for the structured text routine, I think others with a standard license can open the project, just not see the contents of that file. We have standard licenses and recently received some OEM code with a FBD task. It shows up in the tree, and we can look at everything else...just not inside that solitary FBD.

yep – that's my point ... the last time I checked you could get a standard (ladder logic) license for RSLogix5000 for about $2,500 ... I think each additional "language" (Structured Text; Function Block Diagrams; Sequential Function Charts; maybe even Equipment Phases) costs about $900 extra – each ...

my point is that if you don't NEED to add those extra languages for some GOOD reason – then why saddle everybody else with having to deal with the expense – and the extra learning curve involved? ...