PV loses trend information

The pid trend information goes away when pid is disabled in the control logix 5000. The PV does have the correct information in the data logging file.

Welcome to the Forum !

Are you using a Trend object you created from scratch, or a Faceplate that is tied to the PIDE control tag ?

"Trend data goes away when I change screens" is the classic symptom when a PV+ Trend doesn't have the tags properly selected in the Data Log Model or the Data Log Model is not running.

Having the data "go away" when the "PID is disabled" is an unusual complaint.

Are you putting the PID into Manual mode, or literally disabling the instruction ?

Are you using PID or PIDE ?

Could the data "going away" be the displayed values becoming zero ?

Are any errors displayed by the PV+ in the FactoryTalk Diagnostic list object ?

PV losing data

Ken, I did a little more searching on this problem and found out Rockwell has seen these problems in versions 5.1 and 6.0 panelview 1500s. We are using PIDE instructions. What happens is that the data logging file becomes corrupted. The only way to reset this is to clear the log files. I found another site that recommended creating another runtime file and reloading the panelview. What was happening is that the trend pages would only show real time values, not past values. Thanks for your input and fast response.

Are you getting errors in the FactoryTalk diagnostic window when the Data Log Model starts up ?

I am, unfortunately, very familiar with the failure mode of the Data Log Model in some revisions of 5.10 and 6.0 firmware. There are always error messages at Data Log Model startup that allow you to determine if you're seeing those bugs, or seeing some other configuration problem.

Ken, I am not seeing any diagnostic errors. The page with trend data on it clears if you go to another page and then come back to it. It only shows live data.

If you are experiencing the same or similar bug that I was in versions 5.10.x and 6.0.x, there will definitely be diagnostic messages when the project starts up and the Data Log Model attempts to start.

When the Data Log Model starts, each Tag in the Data Log Model generates first a "Item could not be resolved" Warning, then later an Error reading "Invalid Tag Type".

These Warnings and Errors only show up when the project starts up, so you need a big FactoryTalk Diagnostics object, preferably on its own page, with scroll up/down buttons if you're going to see the errors.

If you don't see the Warnings and then the Errors, you are experiencing a problem that is different from the Data Log Model startup bug.

What is the exact firmware of your terminal ? When I experienced these problems, 5.10.00 and 5.10.03 were OK but 5.10.06 and 5.10.08 had the problem.