Data Collection Using Dde/excel

[lynchmob2000 0]

Hello all, A few months back I used the DDE/VB/Excel example floating around here to setup a data collection app. It is working great and a big thanks to chakorules for the example. I have now been asked if there is a way to not allow the machine to run cycles unless the PC is on and running the datalog spreadsheet. I think I can do this simply by using the Excel sheet to "hotlink" to a bit in the PLC then clear it in the PLC based on a timer (i.e. heartbeat). Question is, what is the syntax to write this bit from a cell? I don't use VB very much at all and figured one of you guys would know this and save me some time. The read syntax for a hotlinked cell is =RSLINX|'M1138'!'B3/161 Thanks, Chris

[Ken Moore 23]

Don't know about bits, but I know you can write a word, see below. From the RSLinx help files: The following macro writes a value to N7:0 in a PLC-5 using the RSLinx topic, testsol: This routine will write a word from Excel file RSLINXXL.XLS, DDE_Sheet tab, cell D7: Sub Word_Write() 'open dde link: testsol=DDE Topic RSIchan = DDEInitiate("RSLinx", "testsol") 'write data thru channel DDEPoke RSIchan, "N7:30", Range("[RSLINXXL.XLS]DDE_Sheet!D7") 'close dde channel DDETerminate (RSIchan) End Sub Using VB From the RSLinx help files: T Visual Basic examples: write a word The following program writes a user inputted number to N7:0 when the Write button (Command1) is clicked, and reads the value stored in N7:0 to verify that the number was actually sent. The inputted number is stored in the text property of the text box named txtWrite_val. The returned value is stored in the text property of the text box named txtRead_val. Sub Command1_Click () 'Write value to N7:0 txtWrite_val.LinkTopic = "RSLinx|testsol" 'Define DDE application & topic txtWrite_val.LinkItem = "N7:0" 'Define DDE item txtWrite_val.LinkMode = 2 'Open DDE link (manual) txtWrite_val.LinkPoke 'Poke Data to RSLinx txtWrite_val.LinkMode = 0 'Close DDE link 'Read value from N7:0 txtRead_val.LinkTopic = "RSLinx|testsol" 'Define DDE application & topic txtRead_val.LinkItem = "N7:0" 'Define DDE item txtRead_val.LinkMode = 2 'Open DDE link (manual) txtRead_val.LinkRequest 'Request data from RSLinx txtRead_val.LinkMode = 0 'Close DDE link End If End Sub

[David Nelson 3]

i cant find this download could someone please put a link to it thanks david Edited 8 Mar 2006 by David Nelson

[Mickey 71]

Not sure if this is what you are looking for but http://forums.mrplc.com/index.php?autocom=downloads&showfile=46 http://forums.mrplc.com/index.php?autocom=downloads&showfile=431

[David Nelson 3]

Thanks Mickey

[Chris Elston 78]

And the "Famous" Excel to SLC DDE logger sheet: http://forums.mrplc.com/index.php?autocom=downloads&showfile=134 You can do a download search here: http://forums.mrplc.com/index.php?act=downloads&do=search Change Category to: View All search for "DDE"

[David Nelson 3]

thanks chakorules downloaded it and others i am going to see if this may be something i can use. first i have to see if i can learn how to use excel and visual basic. thanks again, david

[lynchmob2000 0]

Thanks Ken. I was hoping to be able to hotlink directly from a cell, but I think I can work the VB as you suggest. If anyone knows if it can be hotlinked directly (or not), I would appreciate the help. Thanks, Chris

[Nathan 7]

I'm not trying to spoil the fun here, but doesn't some person own the patent on using MS Excel to PLCs via DDE? I'd really like a link/reference to that if anyone has it. My real question is why anyone uses this in the first place? ---- Nathan Boeger Integrator, Microsoft Certifed Systems Engineer http://www.inductiveautomation.com