Can PLC's execute windows programs?

[Twitch]

Hi all,

I am using a Compact Logix 1769-L33ER PLC with RS Studio and Factory Talk View software to develop a protection and control system. It uses a high voltage DC Power Supply that needs to have its voltage applied in a slow ramp-up function. This is currently implemented in a separate script file that is executed by the operator on the host PC.

Is there any way anyone can think of to cause the PLC to initiate (spawn) the execution of a separate windows program (or even a DOS batch file)? Any alternative approach ideas?

I've learned a ton from this Forum. Many thanks to all for donating your time and wisdom. Cheers!

Tim

 

[Steve Bailey]

PLCs run their own proprietary operating systems so you won't be able to use a program designed to run in a Windows environment.

You may be able to duplicate the functionality of the script in a ST subroutine in the Compact Logix.

 

[Twitch]

Ok thanks Steve. I was hoping that since trend data can somehow access the windows file system that other s/w could too.

Forgive my ignorance - what is a 'ST' subroutine?

 

[Steve Bailey]

ST stands for Structured Text, one of the programming language options for the Compact Logix.

 

[TConnolly]

Ramp functions are routinely programmed in the ControlLogix. Ramping is a basic and fundamental control task. The RSlogix5000 instruction set includes some functions that facilitate special kinds of ramps as well as curve fitting.

Do a search on the forum for "ramp" and you'll find lots of examples showing various ways to ramp.

 

[Archie]

Is there any way anyone can think of to cause the PLC to initiate (spawn) the execution of a separate windows program (or even a DOS batch file)? Any alternative approach ideas?

You can monitor a bit from the PC and have the PC launch the program when the bit goes true. How fast would you need the program to launch after the PLC gave the signal? If up to 1 second delay was ok, then it is possible to do.

 

[Twitch]

Thanks for helping guys ...

TConnely: The ramp function is controlled by a C program across an IEEE-488 bus, so PLC ramping wouldn't apply here. That S/W has been around for awhile now and works fine. I was hoping to just use it without modification.

Archie: Hmmm ... an interesting idea. Alternatively the PLC could be armed to wait for a bit hi transition and the PC could set a bit when activated. But I think I like your approach better. It would require an extra I/O card in the PC and extra S/W written but maybe not a bad compromise.

Tim

 

[Archie]

Archie: Hmmm ... an interesting idea. Alternatively the PLC could be armed to wait for a bit hi transition and the PC could set a bit when activated. But I think I like your approach better. It would require an extra I/O card in the PC and extra S/W written but maybe not a bad compromise.

I'm not sure if this is possible in FactoryTalk View, but in AdvancedHMI I have done this with a DataSubscriber monitoring a bit, then when the bit goes true, use a StartProcess to launch the application.

 

[The Plc Kid]

I have used these to do similar things.

http://www.oldi.com/product/4/sam/

http://www.prosoft-technology.com/P...lLogix/In-Rack-Industrial-PC-for-ControlLogix

Prosoft has a Linux development module now also. If the software on your PC has an API available that will make it easier.

 

[The Plc Kid]

Also you can launch an application with FT View but it's purpose is to launch a 3rd party program or app from a button push, etc.

You could make it work with logic from the controller but FT can't close the application once it's launched and the application launches in it's native screen not really inside the HMI app so it's kind of clunky.

Not sure why FT View still does not have a better method to control and embed 3rd party apps. Other HMI vendors have this why Rockwell does not get on the ball is beyond me.

 

[mk42]

I've seen a some customers use Soft PLC's with success as well, which is a program that runs on a standard PC but executes PLC code. Typically they use some kind of realtime OS to still gaurantee deterministic control. Customers going this direction have often utilized the ability to call windows programs from within the PLC code.

I know you already have a CPU specced out for this job, but it may be worth looking at in the future. I think AB has a soft PLC if you want to keep the same platform, although I have no idea what it's capabilities are. It is probably a significantly more expensive solution than your standard compactlogix though.

 

[Manglemender]

Could you use a bit in the PLC to trigger an "Event" in the HMI/SCADA that then used a SHELL command, maybe via a script in the SCADA?

Nick

 

[Twitch]

...So I've stumbled upon the best answer to my own question - use an ActiveX Control:

In Factory Talk View 7.00, select Objects -> ActiveX Control... After drawing a small box on the GUI a "Insert Active X Control" window appears. Browse to the 'ME Program Launcher' item and select OK.

In the ME Program Launcher Properties 'Connections' tab, enter the full spec ProgramLocation for the program to want to run, such as "C:\PLC SW\DCPS_CTRL_ON.EXE" (Quotes required). For the LaunchEnable tag, enter a tag name such that when transitioned from 0 to 1 will cause the program to run.

That's it, works great! More info available from the always present 'Help' button if desired.

Tim