Problems with OPC DA UDS

[Former Member]

Hi,

I have a problem using the UDS to access OPC datasources.

I'm trying to access a server from the company Sartorius Mechatronics. This server is OPC DA 2 compatible.

In OPC UDS 2.5.0.4 Beta the only way to get data is, to set the read mode to asynchronous. If I do so, I can query tag values but it takes about 2-3 seconds per tag and isn't really usable in a productive application.

I tried to use the UDS Framework 4.0, hoping that it would solve my problem. With 4.0 I can't access tags. The OPC server hast two groups and the same items within every group. If I select the UDS in a tag query and try to build the details, all tags are referred to without group name. For example if I add the item ST_WGT_A of group X5_203 to the selected Tags it is added as ST_WGT_A without the leading X5_203. which is needed to access the item.

If I use this OPC server in a standalone OPC client (for example the free opc explorer from http://www.dopc.kassl.de/explorer.shtml) I can access all items without problems and changes of the item's values can nearly be seen in real time (instead of waiting about 2-3 seconds in MII).

Has anyone ideas how to solve this problems?

Regards Timo

[Former Member]

The alias configuration tells me, that it can not connect to OPC server. But it must be able to connect, because I can use the OPC server with this UDS from within MII workbench.

I also realized yesterday that the access to the server is not only slow. If I run the tag query the first time, I get old values different from the one that are really set in the server. Running the query for the second time shows the actual values.

Timo

[Former Member]

The OPC server used can gather information from different weighing machines over a vendor specific protocol.

I can add each weighing machine to use to the OPC server by specifying the name and the IP address of it.

All available OPC items for that kind of device are provided in an OPC group with the name of the device afterwards.

In the current configuration for example I have two weighing machines that are configured in the OPC server.

Name 1: X5_203

Name 1: X5_204

So when I connect with the free OPC client I see two groups (X5_203 and X5_204) in the tree and OPC items with the same name in each of this groups (because both weighing machines are of same type and have same items).

When I select an item the OPC client accesses it with the "full name", for example X5_203.ST_WGT_A and X5_204.ST_WGT_A for the item ST_WGT_A of the both machines. I see correct values of one of the both devices then.

In OPC UDS 2.5.0.4 beta I can also access the items with this full name (but very slow in the asynchronous mode).

In OPC UDS of UDS 4.0 I see the groups in tag query selection menu and also the items. But when I add an item it is accessed by ST_WGT_A instead of X5_203.ST_WGT_A and it doesn't work.

The dialog to set aliases in UDS 4.0 always ends with an exception when I try to brows the OPC server.

Regards Timo

[Former Member]

Timo,

I have configured the two tags with same in OPC server in different groups.And sucessfully added these two in UDS 4.0 using alias configuration. Even I browsed these two tags with two groups in MII tag query and got the output.

What is the error message you are getting?

-Suresh

[Former Member]

Hi,

Why Can't you add a group in UDS itself? It is poosible to create group in UDS using Configure Alias Option. There you can add Group and map tags to particular group.

I want to know from you that did OPC server or client allowed you to add the tag with the same name eventhough it is a different group node.

Even I have got better responses with many number of tags with different OPC servers.It was less than a second.

-Suresh

Edited by: Suresh Hiremath on Jul 9, 2009 2:36 PM