4-20mA in PLC to Charts and Graphs

I am sure this has been hashed out hundreds of times. I've read several post about the pros and cons of Excel.

Here is what I got:
2 Instruments that have a standard 4-20 mA output. These two instruments are on a Control Logix PLC and a MicroLogix PLC. The big dogs want to see some pretty charts and graphs. I got to make it happen and send it down the Ethernet wire. So, having never done that I coming to the world of experts for help. I need simple and easy if possible on both ends. Will ya'll point me in the right direction.

Let me know if you need any more info. I've done alot of programming just never done anything messing with this kind of stuff or ethernet at all.

I appreciate in advance the help.

Do you have RSLinx Pro software? Having it, or similar software, will make a world of difference in how easy this is to do.

(linx lite that comes with your RSLogix software won't fill the bill)

This might get you started:

http://www.eng-tips.com/viewthread.cfm?qid=32838&page=3

1.You will need to "Serve" some Data to them.

Sooo. What connection do you have to your AB device now?

This connection must eventually end up to an Ethernet link to them "Clients".

On the AB side... who cares?.

Remember to keep them clients as farr away as possible from the AB devices. PC+router+hub ... keep them away.

2.Start by an Excel sheet. Write some Data in it.

3.Have this data displayed on another computer.

4.Get the data from AB to Excel.

Yes, I have RS Pro Edition. I hope its easy. For an ole broken down Electrian like me most anything can be hard. The basic's I can handle ... now some of this ethernet stuff is ....flyin a little to high for this ole bird. Yall be easy ....

First you have to find a way to read the values then store them. I would look at the RedLion Data station.

What brand of hardware do you want to use?

With what frequency does this data need to be refreshed?
Is it 1 or 2 times a day or average or live?

They want live data. This is an online system that they want to see wants going on with 2 products. Right now all I have is 2 instruments reading a value and they have to walk out and look at the instrument. They want it "piped" back to the office area via the PLC. Of course all I got is a 4-20 and all they got is Bill Gates! So they want to look any time of the day and see whats going on in these two tanks.

I got to put them something in that will work easy for me and realiable for both!

If you can install RSLinx Gateway or Pro on their PC(s), and create a DDE connection (probably through your PC) then you give them live data in excel format very easily.


If you cannot install RSLinx on their machines, then it can still be done, with a little more work...

EDIT: Now I am not sure if RSLinx Lite (free) can be used...as long as you have Gateway or Pro on the machine connected to the PLCs.

Check under help in your RSlinx pro. Try searching on kewords Excel or DDE. There are some examples right there in RSlinx help that will show you how to get RSLinx to get the data from the PLC and put it right in Excel.

Thanks

"Once you open a can of worm, you find that the only way to get the worm back in the can is to get a bigger can."

Why not prevent any abuse of your system by isloating the INFO part from the control part?

Get an "embedded web server I/O Device". If you search for them or others here can link you to devices they know, you should be able to do all this with only having to install a few cable... your Bosses will only have to use there browser to view the Data.

Those device already have a "Web page" in them that you "see" the Data values. Nothing to program exept the IP address

Install a router and seperate network sub to make certain that it never get clos to you AB PLC.

Here's a bit of scrap code that might help out.


Public Sub GetSettingsFromPLC()

Dim PLCchannel As Long
Dim DownLoadSheet As Worksheet
Dim BbitsIhope As Range
Dim NwordsIhope As Range

Set DownLoadSheet = Sheets("Upload")
Set BbitsIhope = DownLoadSheet.Range("A2:A11")
Set NwordsIhope = DownLoadSheet.Range("B2:B11")

PLCIdent = DownLoadSheet.Range("A2").Value 'Put the name of the PLC here.

Application.DisplayStatusBar = True
Application.StatusBar = "Opening Connection to PLC"
PLCchannel = Application.DDEInitiate("RSLinx", PLCIdent)

Application.StatusBar = "Reading B3 - B Bits"
BbitsIhope = DDERequest(PLCchannel, "B3:0.0,L10") 'Select the range of "B" bits.

Application.StatusBar = "Reading N7 - N Words"
NwordsIhope = DDERequest(PLCchannel, "N7:0,L10") 'Select the range of "N" words.

Application.StatusBar = "Closing PLC Connection"

'close dde link
DDETerminate (PLCchannel)

Application.StatusBar = False

End Sub

Pierre is correct. The Red Lion DataStation Plus device would do this very easily and be real time. You would simply need to connect the DSP to your PLC and then map to the correct tags, create a few Simple Bar Charts on the User Interfrace HMI screen and Enable the Web Browser. The Suits would feast on all that "live" data going up and down. And you could have the DSP send them an E-mail alert when a certain value might be met and tell them to book their weekend Tee times! It would be that easy.

Joe_WaZoo

Quick and Dirty

Ok guys, here ya go. This is the easiest way to go with it.


1) Install RSLinx Pro on the machine you want to display the data on.
2) Configure your ethernet driver to connect to the PLC. (Use Ethernet devices, not Ethernet/IP)
Make sure you can connect to the running PLC
3) Click Edit->Copy DDE/OPC Link... (you may have to configure a Topic under DDE/OPC or whatever, my copy of Linx automatically sets up a new topic for every PLC I establish connection with.)
4) Then Open Excel
5) In Excel, right click in the cell in which you want to display the data before it is converted to the chart.
6) Click paste Link when prompted....
7) This will put the live data from your PLC intoo your spreadsheet, and then manipulate the data in Excel in any way you desire.