Hi folks,
I am working with a Wonderware/IndustrialSQL system for the monitoring and analysis of harmful gases. I want to read the samples from the Runtime SQL database into another system. Now I notice that if the value (e.g. gas concentration) for a tag is constant, no new samples seem to be recorded (no matter what the storage mode). So on occasions, the last recorded sample timestamp for a tag can be several hours old. I would like the re-assurance of recording a regular new ‘physical’ sample every 30 sec or so even if the gas level is constant.
From poking around in the Runtime database and reading the InSQL documentation I gather now how cyclic/delta/forced storage works. The samples are buffered in the ‘active image’ (default 65 samples/tag), then for cyclic/delta the ‘history’ samples may be thinned out. But even when I set up a test tag using ‘forced’ storage, there are still these occasional long gaps between samples in the active image.
I am assuming that the tag value recorded in table/view Runtime::AnalogLive (now Live in version 90), which is pushed into the active image, is the last received sample from the I/O server. But I notice that this value too, even for the ‘forced’ tag, can be one or more hours old at times.
What I am concluding is that the I/O Server is simply not delivering up a new sample unless the value has changed from the last sample? If so, are there any configuration settings in the I/O server (or further back) which will force it to deliver a sample, preferably every 15-30 sec or so? And would these settings tend to be hardware dependent?
As I am new to Wonderware/InSQL/PLCs, I may have completely the wrong end of things! Perhaps I should be reading direct from the I/O server or from the PLC? However it would be much neater if I could read the values from the InSQL Server database, for various reasons.
I did not set up the Wonderware/InSQL system, and it may not be configured appropriately for my requirements. The DbRevision is 54.
Any advice or suggestions would be much appreciated.
I am working with a Wonderware/IndustrialSQL system for the monitoring and analysis of harmful gases. I want to read the samples from the Runtime SQL database into another system. Now I notice that if the value (e.g. gas concentration) for a tag is constant, no new samples seem to be recorded (no matter what the storage mode). So on occasions, the last recorded sample timestamp for a tag can be several hours old. I would like the re-assurance of recording a regular new ‘physical’ sample every 30 sec or so even if the gas level is constant.
From poking around in the Runtime database and reading the InSQL documentation I gather now how cyclic/delta/forced storage works. The samples are buffered in the ‘active image’ (default 65 samples/tag), then for cyclic/delta the ‘history’ samples may be thinned out. But even when I set up a test tag using ‘forced’ storage, there are still these occasional long gaps between samples in the active image.
I am assuming that the tag value recorded in table/view Runtime::AnalogLive (now Live in version 90), which is pushed into the active image, is the last received sample from the I/O server. But I notice that this value too, even for the ‘forced’ tag, can be one or more hours old at times.
What I am concluding is that the I/O Server is simply not delivering up a new sample unless the value has changed from the last sample? If so, are there any configuration settings in the I/O server (or further back) which will force it to deliver a sample, preferably every 15-30 sec or so? And would these settings tend to be hardware dependent?
As I am new to Wonderware/InSQL/PLCs, I may have completely the wrong end of things! Perhaps I should be reading direct from the I/O server or from the PLC? However it would be much neater if I could read the values from the InSQL Server database, for various reasons.
I did not set up the Wonderware/InSQL system, and it may not be configured appropriately for my requirements. The DbRevision is 54.
Any advice or suggestions would be much appreciated.
