ControlLogix - Accumulated operating time

[dalporto]

Hi.

I need suggestions.

I want accumulate operating hours from a simple XIC condition, so I'm thinking a RTO with a 60000 or 3 600 000 preset, 1 or 2 CTU, you catch my drift. The unit can be operating for 1 hours up to 12 months non-stop, if that changes anything. I'm also looking to keep the number of operations on a breaker.

What I'm wondering is how to make sure that I don't lose the count / values on a full PLC download. I'm guessing what you're going to tell me is to make a note of the actual value and put it back after the download, or save / upload values before doing a change, but that is not always possible, and that will be lost anyway if the customer do its own changes later, even if written in the O&M.

So I'm asking if there is another way to try to not lose the values.

I remember I once did something like that with a different brand where I had another PLC on the network at a "higher level", so I had a logic that would give the value back if it was different, or lower, or zero, but this still looks kind of overkill for a stupid accumulated time counter, and more data exchange to set up.

I have the same setup here (PLC at "higher level"), so I could do something like that again, but I'd really prefer not to.

There is also a standalone InTouch HMI on that setup, maybe there is something that could be done using that?

Thanks for your suggestions.

 

[robertmee]

Data preserve download tool....you can download logic updates but retain the tag values. You need fully licensed linx to use.

 

[DaDaDadeo]

Take the 0 bit of the PLC clock's seconds DINT and put an ONS after it to execute an ADD instruction with a "Total_Process_Seconds" DINT tag +1 with itself. Use this tag to calculate the total operation minutes and hours using the DIV function. The MOD function is helpful for reoccurring intervals during a process. The DINT tag should keep its value when the PLC is powered off and back on as long as there's battery or capacitor backup. Clear the "Total_Process_Seconds" tag when an operation starts.

I usually create a bit tag called a "One_Second_Trigger" after the ONS that I use throughout the program for simple 1 second timer accumulators instead of using TON, TOF, or RTO instructions. I reserve those for processes that require more accurate times with a resolution less than 1 second.

 

[robertmee]

Take the 0 bit of the PLC clock's seconds DINT and put an ONS after it to execute an ADD instruction with a "Total_Process_Seconds" DINT tag +1 with itself. Use this tag to calculate the total operation minutes and hours using the DIV function. The MOD function is helpful for reoccurring intervals during a process. The DINT tag should keep its value when the PLC is powered off and back on as long as there's battery or capacitor backup. Clear the "Total_Process_Seconds" tag when an operation starts.

I usually create a bit tag called a "One_Second_Trigger" after the ONS that I use throughout the program for simple 1 second timer accumulators instead of using TON, TOF, or RTO instructions. I reserve those for processes that require more accurate times with a resolution less than 1 second.

That doesn't address the OPs needs of retaining the value on a download...the accumulated value in your example could be hours, days, weeks old in the downloaded version.

 

[DaDaDadeo]

That doesn't address the OPs needs of retaining the value on a download...the accumulated value in your example could be hours, days, weeks old in the downloaded version.

Oops. I read it too fast and I glanced over the "full PLC download". It looks like an external storage such as the HMI or another PLC may be the best option unless a PLC is used that separates the register or tag memory from the logic. A PLC such as the IDEC FC6A retains register values after downloading full logic updates.

 

[robertmee]

Oops. I read it too fast and I glanced over the "full PLC download". It looks like an external storage such as the HMI or another PLC may be the best option unless a PLC is used that separates the register or tag memory from the logic. A PLC such as the IDEC FC6A retains register values after downloading full logic updates.

I'm assuming it's Rockwell with the use of XIC, CTU and RTO mnemonics. Rockwell makes a tool to download logic and preserve the tag values.

 

[dalporto]

Not a lot of information available on Data preserve download tool.

I'll try to check it later.

 

[kekrahulik]

I have come to accept that my various PLC programs may all have data or settings or recipes or .... that I don't want to overwrite. SO I am very careful to upload, make changes, and download.

Of course, when a PLC craps out in the middle of the night, all bets are off. I'll get to explain to people the next day that their reports are probably wrong now. Very grateful I'm not working in a regulated industry.