Experimental Physics and Industrial Control System

Hi,

In our project we are frequently interested in questions like:

1. What were the values of a set of process variables at a given time?

pv_name_1 time_stamp value
pv_name_2 time_stamp value
.
.

2. What were the differences in the values of a set of process variables
at two different times?

pv_name_1 time_stamp_1 value | time_stamp_2 value
pv_name_2 time_stamp_1 value | time_stamp_2 value
.
.

3. What were all the values of a set of process variables between two times?

pv_name_1 time_stamp_1 value
          time_stamp_2 value
					.
          .
          time_stamp_m value

pv_name_2 time_stamp_1 value
          time_stamp_2 value
          .
          .
          time_stamp_n value
.
.

It seems that most archivers are designed for plotting a few process
variables over a long period. I have begun to write an application to
store and query data as I have described, but I am wondering if I am
reinventing the wheel. Does a tool such as this already exist?

Thank you for your time,
Patrick

Replies:

RE: querying for sets of pvs in archived data Emmanuel Mayssat

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