Ab 1769-l24er

Hi
I have a AB 1769-L24ER plc
I have setup a variable to count run time of a motor, it work fine, but when I do a full download the variable get reset is there a way to make it completly retained?

Thanks

If you save your file while online the software will ask if you want to upload the tag values - say 'yes' - then your PC will have the same data as the PLC

julspower said:

...is there a way to make it completly retained?

Click to expand...

danatomega said:

If you save your file while online the software will ask if you want to upload the tag values - say 'yes' - then your PC will have the same data as the PLC

Click to expand...

Only if the motor is stopped when you Upload. If you Upload while the motor is running then the running time will further increment before you stop the motor and perform the Download. The computer will not have the same data as the controller.

I may be splitting hairs if a few seconds or even minutes do not matter, but worth noting I feel?

Regards,
George

No, to my knowledge, (please correct if need be) there is no way to make tag data "completely retained" or write protected during a download. In COmpactlogix the tag data is part of the program so it all comes in together.

There is a way to do what you want.
Its called the Rockwell Software "Tag Upload/Download Tool"

http://www.software.rockwell.com/support/download/detail.cfm?ID=3718

You use this to save all your most current tag data to your laptop.
You can then download the program.
The you write the tag data saved above back to your processor.

Everything is as it was.

Geospark said:

Only if the motor is stopped when you Upload. If you Upload while the motor is running then the running time will further increment before you stop the motor and perform the Download. The computer will not have the same data as the controller.

I may be splitting hairs if a few seconds or even minutes do not matter, but worth noting I feel?

Regards,
George

Click to expand...

George, you are completely correct (go ahead and split those hairs - in many circumstances it's important) - I didn't even consider the motor running time and otherwise active data...

GTUnit said:

No, to my knowledge, (please correct if need be) there is no way to make tag data "completely retained" or write protected during a download...

Click to expand...

GTUnit,

Yes, actually there is, but I'll get to that later.

The Tag Upload/Download Utility is one option if the OP is looking to save one or more tag data values for various reasons including before performing a Download.

However, it had appeared to me that they just wanted to find a "simple" way to make "it completly retained". That is, just the running time tag value.

If you simply Upload that value, while static, make edits that do not affect it, and then Download, it will be retained, even if the controller is power cycled.

Another simple option is to take note of the value, when static, before performing the Download and then write that value back to the tag when done. But that requires a user remembering to do this.

If you have a situation where you want to retain several, many or all tag values, then yes, you would be better to look at other options...

I say "simple" above because the Tag Upload/Download Utility is not so simple an option. You must have an OPC compatible version of RSLinx Classic with an OPC Topic setup to the controller. RSLinx Classic Lite will not suffice. A Single Node licence minimum would be required for a single controller. You must also select, via the Tag Upload Download Tool, which tags you want to exchange via OPC. Once the tag value is saved, and the Download performed, you must once again select the data, using the Tag Upload Download Tool, that you want to restore, and manually update it. This method, while somewhat more involved, does have its advantages. You can select just the tags you require and you can use it while the controller is in Run Mode. This is it's primary advantage really.

The better option, for preserving tag data values, before performing a Download, is to use the Data Preserve Download Tool. This tool can be used, manually or automatically, to save all supported tags and their values to a CSV file. The CSV file is then later used to restore the tag values in the controller.

In Auto, it will Upload tag values and save then to a CSV file. Next it automatically performs an ACD file Download. Then it automatically Downloads the tag values from the CSV file into the controller. While the advantage here is that this is all done automatically for you, and without OPC, there are disadvantages. You can only preserve and restore all supported tags, and not individual tags, and the controller must be placed in Program Mode.

Regards,
George

Thanks guys