While Kepware unofficially supports up to 100,000 tags, real-world performance degrades past 50,000 tags if you are using advanced features (Alarms & Events, Historical Logging, or 20+ concurrent OPC UA clients). Beyond that, you should split the plant into multiple EX instances or upgrade to Enterprise.
| Feature | KEPServerEX (Standard/Connectivity) | KEPServer Enterprise (Tier) | | :--- | :--- | :--- | | Primary Use Case | Single machine connectivity, small skids, simple SCADA. | Plant-wide connectivity, IIoT Gateways, Enterprise MES. | | Tag Count | Limited (based on purchase tier). | Unlimited. | | Driver Support | Most standard drivers (Modbus, AB, Siemens). | All standard drivers + Advanced IoT/Cloud drivers. | | Data Redundancy | Basic. | Advanced (IP Failover, Redundancy). | | Cost Structure | Lower upfront cost for small deployments. Scales linearly with tags. | Higher upfront cost, but better value at scale. | | IIoT Readiness | Requires purchasing specific plug-ins. | Often bundled with IoT Gateway features. | | Deployment | "Lite" or "Pro" installers. | Full installation with all features unlocked. |
Choose KepserverEX if:
Choose Kepserver Enterprise if:
Best for: Single plant floor, standalone machine, or small to medium sites where high availability isn’t critical. kepserver enterprise vs kepserverex
Key features:
Licensing: Per-instance, per-model (tag count, plugin options). While Kepware unofficially supports up to 100,000 tags,
Many engineers assume the standby node sits idle. It does not. The standby node actively polls all PLCs at the same rate as the active node to maintain current values. This doubles the load on your industrial network. If you have 100 PLCs, each polled 10x/sec, the standby node adds another 1000 polls/sec. Ensure your network switches can handle it.
Unplanned downtime in a refinery costs $1M+ per hour. In a data center, it’s even higher. Enterprise provides redundant power supplies, redundant NICs, and redundant servers—all managed through a single configuration. Choose KepserverEX if: