Blog.
Field notes on P&ID extraction, ISA 5.1, and instrumentation engineering.
Archive.
May 2026
- Spare I/O Percentage. How Much to CarryA flat 20% spare wastes budget on DO and under-provisions AI. The number that matters is the one you compute per type, against the client spec.
- The Line List Explained. Contents and SourcesThe line list is the master register of every process line on the P&IDs, distinct from the I/O list and the index, and the input to stress, MTO, and isometrics.
- What Is Not an Instrument. Tags That Don't Belong on the I/O ListAn I/O list counts wired field signals, not every tagged item on a P&ID. Hand valves, local gauges, line numbers, and legend entries carry tags but earn no channel.
- PLCCreator Device I/O List Format ExplainedWorking reference for the PLCCreator Device IO List CSV format. Column definitions, signal class encoding, vendor architecture handling, and conversion notes from a P&ID-derived I/O list.
- ANSI/IEEE C37.2 Device Function Numbers. A Working ReferenceWhat the numeric codes on protection relays and switchgear single-line diagrams mean, where to look them up, and how they fit alongside ISA 5.1 instrument letters on a P&ID.
- How to Read a Cable ScheduleWhat every column on an instrumentation cable schedule means, why downstream users care, and how to spot the most common errors before they reach site.
- DEXPI 1.3 Schema Explained. Process Industry Data Exchange in PracticeWorking overview of the DEXPI 1.3 P&ID exchange format. Schema structure, what fields it carries, ISO 15926 alignment, and when teams pick it over native CAD formats.
April 2026
- API RP 552 Instrumentation RequirementsWorking summary of API RP 552 for transmission systems in process plants. What it covers, what it does not, and how its requirements cascade into instrument selection and P&ID markup.
- SIL-Rated I/O and BPCS Separation ExplainedHow Safety Integrity Level, SIL ratings change instrument selection, I/O list structure, and the hard line between safety instrumented systems and basic process control. Written for controls engineers building an I/O list that a functional safety auditor will accept.
- Commissioning Loop Check Plan. What to Prepare Before the First CheckA working commissioning engineer's checklist for pre-check setup, loop-check sequence, documentation templates, and the things that cause the most delays once the PLC is energized.
- KKS Coding Explained. How to Read KKS TagsA working reference for KKS, Kraftwerk-Kennzeichensystem tag structure in power generation. The function key, equipment unit, and component breakdown levels, worked example tags, and how KKS relates to IEC 81346 and RDS-PP.
- NORSOK Z-DP-002 Coding ExplainedField reference for NORSOK Z-DP-002 tagging on offshore oil and gas projects. System and tag-number structure, example tags, and how the standard interacts with IEC 81346 and ISA 5.1.