pc control

[spanky 0]

I would like to control a (any) plc from a PC. I can write the plc program not sure how to write the computer software program. I would like to be able to start and stop things with the click of a mouse and monitor sensors connected to the plc. Well were do I start? Thanks in advance for any help spanky

[Chris Elston 79]

Somewhere along the lines, your going to need to decide on a communcations protocol. What PLC are you using? That will narrow it down a wee bit for us to help you. In general, sounds like you want to make an HMI. Depending on what PLC, can your application use just a off the shelf HMI, rather than pc based software? If not, there are other ways to make simple HMIs. One time, I used RS Linx Single node, and DDE topics to make an HMI in Microsoft Excel. I had a spreadsheet open that I created buttons that told the PLC what to do in VBA code. Kind of slow, but it worked.....

[TConnolly 13]

First off, you don't really "control" a PLC from a PC. The PLC is the controller. You can send data in the form of discrete bits and numeric values to the PLC, but it is the PLC that executes its own program in response to the data it is provided. Now that that is out of the way, we really do need to know what PLC you want to interface with. Each PLC is different and the requirements to communicate with it vary a great deal from brand to brand.

[TimWilborne 108]

I would hope that by this statement you are talking about a Pc near what you are wishing to operate. If not you may want to look at some of the safety issues first.

[spanky 0]

ok I'm back. I have not selected a PLC yet. I'm interested in some one recommending a complete package. Not sure what all the ddl, hml stuff is. You might have to put that in laymans terms. These plcs will be far from the computer, there will be may be 250 of them all on different independant machines that all work together. The couple of machines that are currently hooked up use a wireless lan to talk to the computer. I'm just interested in getting pointed in the right direction. I need to create a screen that I can click on the machine click a button with the mouse to do some things and more importantly monitor 8 or 10 sensors on the screen. I would assume that some or most PLC's have a feature that may be I can create this screen using the plc's own software. If not what software do I need to learn, where can I get it, and if it is packaged with a plc that will be fine. I will look into using that plc for my needs. Thank You

[Ken Moore 23]

Plc software is for programming PLC's not PC's. Sounds like your best choice would be one of the major SCADA software companies, such as GE/Intellution, Wonderware or Citect, just to name a few. These software packages are not cheap. However, all the major brands, pretty much can communicate with almost any PLC. Then you could have your machine interaction, data monitoring, data history, report generation etc... Some of these packages may have downloadable demo's can't say for sure. Just google SCADA software and check out the links. So... As mentioned earlier, you need to decide which brand of plc, and which communication protocol you are going to be using FIRST. Go to this link: http://www.iainsider.co.uk/scadasites.htm it has a lot of useful SCADA links

[entertron 0]

Spanky, What you are asking for can be done by just about any PLC...for which there are many, however, I will suggest what I am familiar with, and those are the controllers my company manufacturers. Entertron Web Site Based on the number of I/O, a micro PLC should be sufficient. The wireless lan you are currently using will need to have some sort of serial connection, in order to interface with the PLC. If you are looking to source other lan products, Aerocomm offers an inexpensive product that we have worked with in the past. Aerocomm product page On the front end, or PC end, I would consider an HMI package that is already done and can be programmed. We market a product from KEP called Infilink. Here is a link to the product information and downloads - HMI Software page You can download a development package with 1 hour run license to see if it is what you are looking for. Another option for your front end software, if you have the time is creating something in visual basic - this would cost less up front, but would require an investment of your time. Disclaimer...I am employed by Entertron, so the information presented is biased. Hope this is information you can use. If you have any questions regarding the information I have provided, you can either call or email from our web site. God Bless, Stephen Luft Edited 8 Dec 2005 by entertron

[Sleepy Wombat 27]

DDE (not dll)- Dynamic Data Exchange (a way for programs to share info between them) a dll is a dynamic link library a compiled file that programmers use to access embeded code function. HMI - Human Machine Interface (OMI - Operator Machine Interface) Hope i don;t sound rude but what past experience do you have with industrial controls, sensors ? If they already talk to a computer what package are they using etc, did you configure this system?Do the existing machines have PLC's in them? From what you have told us 250 * 10 = 2500 pt's sensors feed back PLUS in addition the magic button you mentioned also... What are the consequences of starting a singular machine etc What are the possible safety consequences of starting the system from a hidden little office whan a maintenace man is fixing the machine etc. It certainly sounds like an interesting project, but on the same instance it sounds like you are jumping into the deep end of the pool with out being able to swim.

[gravitar 3]

Please elaborate on your statement, "do some things". As long as you're just monitoring I/O from the remote PC, you're safe. If you want to be able to alter the PLC's memory, change the data tables in any way, or, most importantly, control outputs, then you have VERY SERIOUS safety consequences to deal with. Here's my recommendation. If you have PLENTY of time to make this happen and the remote station is READ ONLY, go ahead and educate and implement this yourself. You've already made a big step in the education phase by finding this website. If at any point however, you think you may want to write ANYTHING to the PLCs, stop and get an integrator involved.

[spanky 0]

All of this has been done before. This is no new thing in the snow industry just new to me. Thanks for all the help.

[TerryRWood 0]

We use Microsoft Visual Basic 6.0 and a program called IN-GEAR OCX for Allen Bradley. It allows us to do anything we want with an interface, show and enter Interger data, control Bit status, show status lights, ..... What ever you can imagine. Look them up at http://www.plcdriver.com/ Terry

[TimWilborne 108]

I've used Pc to remotely turn on generators or switch to secondary systems but I know some that use computers to remotely operate machines that people are near. Still scares me