Over the last few weeks many of our readers made use of our “submit a question” link to send us topics they'd like to see us cover, and today I'll share a few of them along with my take on how to resolve each question.

Note: Readers can ask submit questions directly for me to answer weekdays at Automation.Locals.com, or submit them on the blog here if they'd like us to consider covering them in future Q & As.


Question 1:

The clocks on AB PLCs can drift as much as a minute a week. I run dept schedules on my PLCs to reset part counts, trigger reports, and other things like that. What is the best way to synchronize the clocks on all of your PLCs? I currently use the Clock update tool, but it has to be running on my computer to keep the time's synced.

Shawn's Take:

The Clock Update Tool is definitely one option.

Another is to have your HMI or SCADA system to update the same “Time Tags” in your PLCs. With View Studio ME and SE this can be accomplished by using Global Connections.

The advantages of using your PC based HMI or SCADA is that your PC is likely already sync'd to internet time. As far as using an HMI, most HMI's have more accurate clocks than what you'll find in a PLC, and you can easily make a display on the HMI to allow a qualified operator to tweak the time if you wish.

On the PLC side, the Status Files in the PLC-5, SLC-500, and MicroLogix are where you'll find the time tags. With ControlLogix and CompactLogix you would need to create your own tags and then use the SSV instruction to set the controller's time to these tags, similar to how the GSV instructions are used to get the controller's time as discuss in our previous article here.

A final way it to use a newer Rockwell product like the 1756-EN2T, to sync with a grand master clock, as we discuss in our article here, and you'll find Rockwell's white paper on the topic here.


Question 2:

I have a ControlLogix PLC which has a SD Card. The image of the main program is on this card. I copied the image to my pc, but could not open it with RSLogix 5000 because this image file format is p5k. Can u help me to convert this file to ACD or L5k file please?

Shawn's Take:

While platforms like the S7 PLC line from Siemens do support this functionality, unfortunately Rockwell has never supported this, and as far as I know has no plans to in the future?


Question 3:

Assign a key assignment to a PLC bit for remote navigation without global connection

Shawn's Take:

There's really not very much information here, so I'm going to make the assumptions that you are talking about the PanelView Plus.

Aside from actually selecting screen on a PanelView Plus (or remotely via ViewPoint,) there is only ONE way to change screens from the PLC, and that is to use global objects which I cover in this article as well as this article.

If you think about it, it really doesn't make sense to include two features in a product that have the very same function. And unlike View Site Edition, the PanelView Plus is a simple HMI without scripting capabilities.


Question 4:

I have a new ML1400 series C. It always faults whenever there's a power cycle and all settings like IP address and programs erases. I have changed the battery. I also program with RSlogix 500 v11. I only see series A, B on the list of processors. What could be the problem?

Shawn's Take:

Is the MicroLogix set to load from Non-Volatile memory every time it powers up? This would be my first guess.

If that was not the case, next I would suspect your power source is producing a sizable spike that is clearing the controller's memory. We often see this happen when lightning strikes near a facility, but it can also happen with switching of large loads.

If those first two issues are ruled out, I would next try to rule out your program by creating and downloading a blank program to see if the issue persists.

And the final option would be to get a warranty replacement from your supplier.


Question 5:

I need help in converting my program written in RSlogix500 to RSlogix5000, because I don't have the RSLogix Project Migrator. Can you do it for me, even for a fee?

Shawn's Take:

As I recently discussed in my article here, Rockwell no longer makes the Project Migrator available as a free download.

If you have access to the installation files for v19 through v26 you should find the Migrator or Translation Tool in either the RSLogix/Studio 5000 folder, or in the Tools folder.

Otherwise, if you have RSLogix 5 v10 or RSLogix 500 v12, you can simply save your file as an ACD as I discuss in this article.


If you'd like to see our previous Q & A's, click here.

To submit a question for us to consider covering in a future blog, click here.

Those readers who'd like to ask me questions directly, can do so here.

Sincerely,

Shawn Tierney
Automation Instructor and Blogger

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