# Engineering Systems Toolkit — 477 Diagrams & Field Tools

> 477 Diagrams & Field Tools (iPhone/iPad app by Yuhsiu Lai.)

- Source: https://appshunter.io/ios/app/engineering-systems-toolkit/id6767090529 (this page in markdown: same URL + `.md`)
- Developer: [Yuhsiu Lai](https://appshunter.io/developer/433114647)
- Category: Education, Reference
- Price: $7.99
- Age rating: 4+
- Requires: iOS 17.0 · 1.3 GB
- Languages: English
- Released: 2026-05-07
- Data updated: 2026-05-23
- User reviews in markdown: https://appshunter.io/ios/app/engineering-systems-toolkit/id6767090529/reviews.md

## What is Engineering Systems Toolkit?

This app is the definitive visual reference for working engineers, technicians, students, and inspectors. Browse 477 professional-quality diagrams spanning 8 major engineering disciplines — all offline, all in one app.
WHAT IS INSIDE
477 illustrations organized into 8 engineering categories:

Electrical Systems — power distribution, panel wiring, conduit layouts, load centers
Fire Alarm Systems — initiating devices, notification appliances, control panels, wiring
HVAC Systems — air handling, duct networks, chilled water, refrigerant circuits
BIM and Construction — floor plans, riser diagrams, coordination views, LOD references
Enterprise IT — network topology, structured cabling, data center layout, TIA-942
PLC and Automation — ladder logic, I/O modules, PLC panels, field instrumentation
SCADA and Controls — RTU diagrams, HMI screens, Modbus/DNP3 architecture, control loops
RF and Radio Systems — antenna configurations, path diagrams, repeater systems, link diagrams

GLOBAL SEARCH
Search all 477 diagrams instantly by name across every category. One-tap category filter chips let you narrow results to a single engineering discipline in seconds.
DIAGRAM OF THE DAY
A fresh featured diagram appears on the home screen every day — automatically curated from all 8 disciplines. A new reference point every time you open the app.
SHARE ANY DIAGRAM
Send any illustration directly to colleagues, students, or inspection reports using the iOS Share Sheet — available from every diagram in the gallery.
ENGINEERING CALCULATORS
Each category includes a dedicated field calculator:

Voltage Drop — NEC K-factor conductor sizing with pass/fail at 3% threshold
Battery Standby — NFPA 72 battery Ah sizing for fire alarm panels
HVAC — CFM airflow, cooling load in BTU/h and tons, duct sizing at target FPM
BIM Space — multi-room gross/net area, GFA, and volume in imperial or metric
IT Network — PoE budget (802.3af/at/bt) and IPv4 subnet calculator with CIDR
PLC I/O — module count, chassis sizing, and scan time estimation
RF Link Budget — FSPL, path loss, link margin with fading environment presets
SCADA Timing — Modbus RTU frame timing, T3.5 gap, and DNP3 poll cycle load

STANDARDS REFERENCE
Built-in searchable reference covering NFPA 72, NEC, ASHRAE, ISO 19650, IEC 61131-3, IEC 62443, TIA-942, and ITU/FCC standards — filtered by engineering domain.
KEY FEATURES

Swipeable full-screen gallery — page through every diagram in a category
Pinch-to-zoom — inspect fine detail on any illustration
Favorites — star and collect your most-used diagrams
Works fully offline — no internet connection required
iPhone and iPad — optimized for all screen sizes and orientations

Whether you are reviewing a design, studying for a certification, or troubleshooting a system in the field, this app puts 477 reference diagrams and professional engineering tools in your pocket.


## Version history (last 2 releases)

### 2.0 — 2026-05-19

Version 2.0 introduces four major new features:

Global Search — search all 477 diagrams by name across every category, with one-tap category filters
Diagram of the Day — a new featured diagram surfaces on the home screen every day, drawn from all 8 disciplines
Share Any Diagram — send illustrations to colleagues or reports via the iOS Share Sheet directly from the gallery
8 Field Calculators — purpose-built engineering calculators for every category, including NEC voltage drop, NFPA 72 battery sizing, ASHRAE CFM, PoE budget, FSPL link budget, and Modbus RTU timing

### 1.0 — 2026-05-07

No release notes.

## More apps by Yuhsiu Lai

- [Availability and Reliability](https://appshunter.io/ios/app/availability-and-reliability/id435033141)
- [Battery Capacity Calculator](https://appshunter.io/ios/app/battery-capacity-calculator/id445176473)
- [48VDC Power System](https://appshunter.io/ios/app/48vdc-power-system/id449477913)
- [NEC Electrical Code Tools](https://appshunter.io/ios/app/nec-electrical-code-tools/id469334093)
- [Engineer's Toolset](https://appshunter.io/ios/app/engineers-toolset/id478486737)
- [Battery Current Simulator](https://appshunter.io/ios/app/battery-current-simulator/id488430945)

All apps by Yuhsiu Lai: https://appshunter.io/developer/433114647

## Related topics

[engineering systems atlas](https://appshunter.io/ios/topics/engineering-systems-atlas)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-05-23.*