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Why is KEPServerEX Skipping or Not Receiving Updated Device Values?


Last Update: 11/7/2018

If the server is not receiving device updates and the quality of the tags or items is Bad, please call Technical Support.

If the server is skipping device updates but the quality of the tags or items is Good, the server may not be polling the device fast enough to receive all the device data changes. To find missing updates, look at the data's beat pattern, which is the rate at which the data is changing versus the rate at which the data is being polled by the software. If the data is changing at the same rate at which it is being polled, it is possible that an update will be missed. This can occur despite the PLC's accurate timing because the PC shares its CPU processing time among multiple running applications. When connecting to a serial device, there is also a chance that the data is changing faster than the device can receive and respond to the poll requests.

The server handles device poll rates differently depending on the type of client application that is connected. Client applications can get data from the server or devices in several ways. For OPC client connections, the Update Rate is controlled by the client (for example, the Group Update Rate in the Quick Client). For non-OPC clients using DDE, AdvancedDDE, FastDDE, SuiteLink, or Intellution PDB connections, the server will poll the device for data at the rate specified in Tag Properties under the Tag Update Rate or Alias Update Override parameter.