Issue: Error Message Quality BAD is Displayed When Reading Items

Issue

The error message Quality BAD is displayed when items (variables) are read.

Cause 1

No connection to the controller is established.

Solution 1

Several solutions are available for this cause:

oVerify the status of the __CommState item as described under Groups and Items if it is supported by the client you are using.

oStart the server in test mode and read out an item. If the server returns the quality status GOOD, verify the connection to the controller.

Cause 2

No connection is established between the OPC server and the gateway server/Gateway Management Console.

Solution 2

Verify whether the icon of the gateway server/Gateway Management Console in the Windows notification area is active. If necessary, restart the gateway.

If there are instances of the OPC server and the gateway server/Gateway Management Console still active as processes in the memory, end these Processes manually via the Windows Task Manager.

Cause 3

One single variable (or item) is greater than the buffer size (byte) set in the OPC configuration tool.

Thus, the quality of all items is classified as BAD. The maximum buffer size for the PacDrive M controller, for example, is 1500 byte.

Solution 3

Verify the setting of the buffer size in the OPC configuration tool. Verify whether a single variable (for example, an array) is too large.

Cause 4

Group or item inactive.

Solution 4

Enable the group or the respective item in your OPC client.