PLCS's Databases

A

Thread Starter

AHERRERA

I have system's with PLC's (500 family)but I want to make a data base in a computer to follow different signals, The data base should include the time and date for each bit or word every time it changes.

Does any one know how to do it?

Thanks in advance.
 
Use a SCADA system. Citect would be a good choice as the alarm summary page can be set up to do exactly what you want.
 
What is ur PLC Make?
You will need a pc-based driver to talk to your PLC and you need to write an application wherein you monitor the PLC values and push them in a database.
All this will become very simple, if your PLC has an OPC Server (consult the provider). Then u can write an OPC Client Application in visual basic to monitor values and can push them in a database.
Search the internet for Demo OPC CLient Applications.

[email protected]
 
R
Try with RSLinx Object Model.
There is a Event for Data Change you can use.

The following is the structure of OPC Server.
you can find the complete document at
http://www.opcfoundation.org

4.4.6 OPCGroup Events
4.4.6.1 DataChange
Description The DataChange event is fired when a value or the quality of a value for an item within the group has changed. Note the event will not fire faster than the update rate of the group. Therefore, item values will be held by the server and buffered until the current time + update rate is greater than the time of the previous update (event fired).
This is also affected by active states for both Group and Items. Only items that are active, and whose group is active will be sent to the client in an event.
Syntax DataChange (TransactionID As Long, NumItems As Long, ClientHandles() As Long, ItemValues() As Variant, Qualities() As Long, TimeStamps() As Date)

Part Description
TransactionID The client specified transaction ID. A non-0 value for this indicates that this call has been generated as a result of an AsyncRefresh. A value of 0 indicates that this call has been generated as a result of normal subscription processing.
NumItems The number of items returned
ClientHandles Array of client item handles for the items
ItemValues Array of values.
Qualities Array of Qualities for each item's value.
TimeStamps Array of UTC TimeStamps for each item's value. If the device cannot provide a timestamp then the server will provide one.
Remarks If the item values are changing faster than the update reat, only the most recent value for each item will be buffered and returned to the client in the event.
Example Dim WithEvents AnOPCGroup As OPCGroup
Private Sub AnOPCGroup_DataChange (TransactionID As Long, NumItems As Long, ClientHandles() As Long, ItemValues() As Variant, Qualities() As Long, TimeStamps() As Date)
‘ write your client code here to process the data change values
End Sub
 
W

William Delatorre

Try a Scada software ( rsview32, wonderware etc) and from inside run and enable an ODBC ( access, etc) to collect data, you define the tags.
You must have OPC running in the background.

William Delatorre
 
J
By 500 family, I assume you mean AB SLC 500 line of PLC's.

The obvious route would be to purchase RSView, WonderWare, or any other of the myriad of products that are designed to accomplish this exact task.

--Joe Jansen
 
R

Rokicki, Andrew

More obvious to me would be get http://www.lns-saginaw.net/index.php
ABEL library to get data directly from PLC.
Then use http://www.freetds.org/ freeTDS library to load data into the database (assuming you have MSSQL data base). Or different dB library depending on data base used. By the way you don't have to purchase anything.

Joe this is not to attack your response. I am just being a wise a??. and/or pointing out Microsoft/AB solution is not the only solution/obvious.
 
I've been considering a similar project and I'm under the impression that Rockwell's RSSql product is available specifically for this application. Probably much simpler than coding your own from scratch.

Regards
 
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