Lost values - compactlogix

Hello,

My problem is right now, that when I am downloading a new
program into my compactlogix the values I got on my panelviewplus
- terminals are overwritten.

Is there also another solution than making first only terminal-
internal variables and writting them then on the controller
- values or making an initialization - program for this
inputs?

Thx for help

Maybe. On the SLC series processors, there are two "protection" options to prevent registers from being changed on download or from being changed at all. I don't know if Logix5000 has a similar feature. Search "Protection" in the Logix5000 help files and see what comes up.

The "Static" protection for SLC-series will prevent the registers being overwritten on download. However, it also prevents them from being written by a PanelView or any other HMI, so if the registers you are trying to protect are intended to be interactive you still need to write some initialization and buffer logic to use them in the HMI.

Take a look at this:

http://www.software.rockwell.com/support/download/detail.cfm?ID=2788

It's kind of a pain as it makes program downloads a three-step process. But it should do wha tyou need.

Keith

I'm just thinking out loud here, but maybe you could one shot your PLC values to the PV+ at first scan?

I just made it like this that I set up something like a firstscan,
which is loading some startup values.

But also it´s working easy when I was setting up my recipes in
my panelview - plus main terminal.

That get´s me to a different question:

I can load up the values from my controller into the selected
recipe.
Also I can load up and in the same time create a new recipe with
this values.
But how can I delete a recipe due to working only with
the terminal?

dmroeder said:

I'm just thinking out loud here, but maybe you could one shot your PLC values to the PV+ at first scan?

Click to expand...

What do you mean? How would you do that?

fieldprog wrote:

... But how can I delete a recipe due to working only with
the terminal?

Click to expand...

With RSView ME or SE, you can't. Apparantly RS hired the same people who write software for the credit score companies; there is no "Delete" function for recipes.

Anybody have a workaround for this?

I would be allready happy if there exists an option to rename the

existing one´s. Because the problem is when the end-user is using

the recipes he wouldn´t be able to delete wrong or old ones, or

rename them. Also its possible to make 2 recipes with the same name

I think, which will cause some troubles.



Because of loosing the values I´ve got in my panelview plus -

I found something interresting: When I´m downloading the program

to the controller, it is overtaking the offline - values of my

variables. That was fun, because another programmer loaded up

the program while my line was running. Then loaded this one later

, and I was wondering first why the hell my whole machines with

no external start - signal moved when this happend.

So there is also no possibility to rename the recipes?

fieldprog said:

I found something interresting: When I´m downloading the program to the controller, it is overtaking the offline - values of my variables. That was fun, because another programmer loaded up the program while my line was running. Then loaded this one later, and I was wondering first why the hell my whole machines with no external start - signal moved when this happend.

Click to expand...

Forget your recipies for a while. First, you need to go through that program, and any like it, and make sure that on S:FS (System First Scan), you manually unlatch, reset, turn off any outputs that can cause motion when the PLC powers up, goes from Program to Run mode, or goes to Run from a Download.

PanelView + terminals always read the 'Device' values from the controller (PLC). Unless you have macros programmed in the terminal, it will always just show the values in the PLC. If you download a new program (or an updated one), then you will most likely have different values than those on the terminal.

You can use the Tag Upload/Download tool, but it's important to remember that even then, if you use LATCHING (OTL) 'Run' bits, then if you upload the tag database from the controller while it is running, download a new (updated) program, and then download the tags again, you could still end up with a dangerous situation. And, that tool will most likely at least partially fail if you have changed the structure of a UDT in Logix.

Depending on how well-designed the rest of the control system is, I suppose you could cheat a little, and have the PLC drop out a relay in the machine E-STOP circuit, requiring a manual reset and start command to proceed, but that is highly dependent on your system.

A good general rule to follow, is "All Un-Commanded Motion is Dangerous", that is, if an operator does not initiate motion, either with a start button, or a go button, or something similar, nothing should move no matter how many times the PLC power is cycled or transitioned to and from run mode.