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VIP Not Getting New Data From ION Devices

Goals and Symptoms

VIP Not Getting New Data From ION Devices
Data from the VIP appears to be wrong.

Symptoms
In Designer you can see the values on the inputs of a VIP module but the VIP Module doesn't seem to be processing that same data. For example, an arithmetic module might try to add two values from a meter. In designer you can see the inputs to this module as, say, 23 and 54. The formula is to add these two values. But the output of the module remains at 0.

Causes and Fixes

Cause
The VIP is holding stale data.

When you look at the values of the inputs in Designer the system is actually going to the meter with a high priority one-shot program to retrieve the values.  You are not seeing what the VIP is seeing in its inputs.

Meanwhile the VIP is doing its regular polling of all ION Devices it needs data for. And this polling is competing with all of the other ION clients (e.g VISTA, LogSrv etc).

To validate this problem, create a Data Monitor module in the VIP and point it at the ION Device.  Let it run and then check the update period.  This will tell you how long it takes for the VIP to see new data.

Resolution

By default the VIP polls at a LOW priority.  You can try to reset this priority higher, say to MEDIUM, but remember that this means that other clients will now not get updates as quickly. 

The overall bottleneck is access to the serial communication port. Close VISTA diagrams that look at devices on the constricted port. Disable unneeded Data Recorders on ION devices on this port. This means the LogSrv doesn't have to upload unneeded logs.

As an alternate application, use the VIP as a concentrator.  Let the VIP bring in the values of interest for its internal calculations and then reconstruct the Vista diagrams to get the values from the VIP. Vista would not contend for the port.


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