Controls › SCADA & HMI
Historian & Data
Collecting, compressing, and retrieving process history.
Written guides in this section
Full references, procedures, and diagnostic guides published under Historian & Data.
Historian Architecture
How process history is collected, stored, and served: the collector, the archive, and the client layers, where the historian sits relative to SCADA and the DMZ, single-server and tiered designs for a utility, the store-and-forward buffer that survives outages, and the sizing that decides how many years fit on a disk.
9 min readUpdated Sep 5, 2026
Historian Data Collection
Deciding what the historian stores and how often: polled versus exception collection, the deadband per tag, rates for control loops, levels, totals, and compliance values, timestamps at the source, quality codes, calculated tags, and the tag list review that keeps a historian from filling with noise and missing what matters.
9 min readUpdated Sep 5, 2026
Historian Compression
How historians store years of data on a disk: exception deadbands at the collector, swinging door compression at the archive, what each discards and what it keeps, the settings that turn a trend into a staircase, lossless alternatives, and how to check that the compressed data still tells the truth.
8 min readUpdated Sep 5, 2026
Trending
Using historian trends to understand a process and diagnose a problem: pens that belong together, scaling and time ranges, raw versus averaged data and what compression hides, overlays and cursors, event markers, and the patterns that point at each cause.
9 min readUpdated Sep 5, 2026
Reporting from the Historian
Turning history into the reports a utility must produce: the monthly operating report, compliance reports for the regulator, daily operator summaries, pump run and energy reports, the calculations behind daily minimums, maximums, and totals, handling bad quality and gaps, and building reports once so they run every month without an engineer.
9 min readUpdated Sep 5, 2026
Long-Term Storage
Keeping historian data for years: a retention policy by data class that follows the record rules, tiered storage from online to offline copies, downsampling, archive management, exports that outlive the historian, and the annual proof that old data reads.
9 min readUpdated Sep 5, 2026
Topics in this area
Historian Architecture
Historian Architecture — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
Data Collection
Data Collection — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
Compression
Compression — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
Trending
Trending — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
Reporting
Reporting — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
Long-Term Storage
Long-Term Storage — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
SQL Integration
SQL Integration — practical reference notes for controls engineers, integrators, and technicians working with historian & data.
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