Issue
Managing communication between I/NET and StruxureWare
Product Line
EcoStruxure Building Operation, TAC INET
Environment
- I/NET Enterprise server level integration
- I/NET Automation server level integration
- StruxureWare Building Operation 1.6.1.5000 and above.
Cause
Users should manage data flow on the controller LAN in order to maintain efficient communication.
Any binds to objects under the I/NET interface follow the settings for the INET Global device scan rate (min) and the INET Global point scan rate (s). By default, this is set to 60 minutes for device status and 5 seconds for point bindings.
The INET Global device scan rate (min) is used to monitor online devices. A device will show offline sooner than the configured setting as all points would show offline.
The INET Global point scan rate (s) is applied to all binds between StruxureWare and I/NET. Opening a graphic or watch window will ignore this rule and immediately request values. After that, the scan will update according to the configured setting.
A controller can either follow the Global scan rates as by default or use its own setting. When a controller has the property DCU scan rate or point scan rate set to 0, it will follow the scan rate configured for the I/NET interface.
An I/NET 19200 speed Controller LAN will handle a maximum of 10 token cycles per second. Each cycle allows a single packet of information to be passed from a single controller to the server. 1 Packet can contain all data for up to 18 points on a single controller. This means binding to manual, value, and PvControl for 18 points on a single 7718 will take one packet. Binding only the value of 5 points on 5 different controllers will take 5 packets. Adding devices to the controller LAN and adding additional polling will slow down the number of cycles per second on the controller LAN.
Resolution
All active binds will poll every scan interval. Graphic binds are only active when the graphic is open. Trend Logs will poll every scan interval regardless of the log configuration options.
Whenever possible, use the I/Net Alarm and Trend objects rather than creating separate StruxureWare alarm and trend objects.
Trend Log Best Practices:
- Use the I/NET Trend Extension as outlined in Using I/NET trends in StruxureWare Building Operation please refer to the online help guide for complete information.
- Create Extended Trend Logs of this information for long term storage.
I/Net Alarm Best Practices:
- Use the I/NET point extension to configure the alarm to be triggered by logic within the I/NET controller.
- I/NET Alarms have 3 priority options which are Routine, Priority, and Critical. This can be globally assigned to any priority using the I/NET interface messages tab.
- Other StruxureWare Alarm enhancements are available to I/NET objects as well.
Scheduling and programming I/NET from StruxureWare
- Whenever possible, bind values to a single I/NET controller per controller LAN and then create I/NET Global/Indirect point relationships to distribute this value to other devices on the controller LAN. Using a single controller allows more information to be sent per packet. I/NET Global points will only broadcast on change. In this scenario, the server is polling a single controller ever scan interval and then on change all other controllers are updated.
Increase the Point scan rate
- Using the information above you should be able to calculate how many packets are required for your system for each token pass. If this number increases to the point that more packets are required than are possible in the default 5 seconds, increase the scan rate. You can increase it on specific over loaded controllers or on all controllers together.
