Troubleshooting the CygNet OPC UA Server

The following tips might be helpful in solving issues that may arise when using the CygNet OPC UA Server.

Subscription Considerations

When subscribing to large numbers of points, it is recommended to use a single Subscription for multiple MonitoredItems. We recommend between 5,000 and 10,000 MonitoredItems per subscription. If you run into issues with a large number of Subscriptions or MonitoredItems, you can increase one or more of the following parameters by adding these elements to your CygNet OPC UA Server configuration file. See Server Configuration for more information about how to do this.

<MaxMessageQueueSize>
<MaxNotificationsPerPublish>
<MaxSubscriptionCount>

Subscription Process Time

The more CygNet points that you subscribe to, the longer the full subscription process will take to complete. Below is a chart that estimates the time, in seconds, that the full subscription process will take based upon the number of CygNet points being subscribed to. The measured times include the retrieval and publishing of each points current value. Your results will vary depending on attributes of your host machine and network environment such as CPU, memory and network latency.

All Point Values - Subscription Time (Sec)

Subscription Time (seconds by point values)