Micrologix Program assistance

toddp65

Member
Join Date
Aug 2014
Location
Florence, Ky
Posts
280
Hi All,

I have a micrologix program i created for our small microbrewery glycol cooling cooling and steam heat of various vessel.
I'll try to upload the rslogix program. Under the HLT temp routine the program will function well for a day and then it won't. Despite the actual temp being below the setpoint the valve logic will not enable. It's at a remote location so i have to drive to get it to. The other day I tried to go online and troubleshoot but it asked for a download so i didn't get to see the issue in action. I'll be heading over there later in the week. A power down of the system doesn't solve and oddly the temp okay indicator says it's good when in fact it's still below SP.

Is it a scan issue or something I'm missing?

This is connected to an AB Panelview 800


TIA
 
Hi, from what I can see, I would not use a GEQ and an LEQ for the same source A value. I am using a lot of these compare instructions in a job I'm doing and I had problems with that. Use a GRT or LES for one of them and a GEQ or LEQ for the other.

And of course you know that when you try to go on line and it asks you for a download (or upload) then something has changed. However, and I can't remember which one, some of those micrologix you had to go offline and download every change (no on line editing) I had one in Alaska, real pain.
Hope this helps a little.
 
If the program you have doesn't match, then when you try and Go Online it'll say no file found and search for a .RSS file in your projects folder that matches the processor name and type.

You can browse to select the file you want to use comments etc from then select "Upload Use File".

You'll then end up with a merge of the currently running program and your old comments.

Then figure out what's new... and go kick that guys butt for not sending you the latest copy!
 
Saffa, then I'd kick my own butt! I made the program--not sure what had changed. With a 1400 you can do online editing, not sure about older micrologixs though.

Saultgeorge--yeah, after looking at the code I realized that about the LEQ and GEQ that when it was at setpoint they'd be fighting--I'm going to change that directly.
 
Am I missing something? You say it only happens when they disable the system via the HMI. If the system is disabled I would expect it to not work. If that's the case, what is the problem?
 
LoL...firejo...yeah, he says when he disables it so the vessel doesn't hog all the steam when they're brewing and the enables it when the kettle cycle is complete...so a change in state and then back and then it doesn't function correctly...am I missing maybe a one shot?
 
The circled logic is suspect. You have opposite states of the same bit in series.
Having the GEQ and LEQ means that both bits can be true at once, specifically when the target temp is reached.

attachment.php


Naming your Enable bit "HLT_Off_From_HMI" is backwards in my opinion, name it what it does when true. When true, it is "ON", not "OFF". This doesn't affect operation, just a peeve of mine.

I don't see any missing oneshots, as long as the enable bit is a toggle (maintained) in the HMI.

Online editing is allowed in the ML1400 (as long as it is not a MSG rung)
Here's how I would change it:

attachment.php


PLCtalk 1.png PLCtalk 2.png
 
Last edited:
Okiepc--thanks, that's exactly what I did but won't be able to check and make changes til Friday; hen I originally programmed the bit from the HMI I wasn't sure what state the button and the instruction was going to be in until it would operating and I didn't change the name. Thanks!
 

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