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Session orientation skill for Claude working on the HydroMind AI project with Arun (Crane Supervisor / Hydraulic Systems Specialist, EnerMech, Abu Dhabi). MUST be loaded at START of every session before any code, file, or git operation. Triggers: ANY HydroMind task, coding request, file edit, git push, KB entry, Android app build, page redesign, or backend change.

By arun25hyd schedule Updated 6/6/2026

play_arrow Run Skill in Manus View GitHub

name: session-skill version: v4.3 date: 2026-06-05 description: > Session orientation skill for Claude working on the HydroMind AI project with Arun (Crane Supervisor / Hydraulic Systems Specialist, EnerMech, Abu Dhabi). MUST be loaded at START of every session before any code, file, or git operation. Triggers: ANY HydroMind task, coding request, file edit, git push, KB entry, Android app build, page redesign, or backend change.

Claude Session Skill — HydroMind AI Project v4.0

RULE 0 — LOAD THIS FIRST, ALWAYS

Before writing a single line of code:

Read this file fully
State exact files to touch
ONE question only if critical parameter unknown
Execute — no guessing, no repeating

RULE 1 — EXECUTION PROTOCOL (NON-NEGOTIABLE)

INSPECT → PLAN → EXECUTE → VERIFY LIVE → COMMIT

Step	Action	Tool
INSPECT	Read actual file structure — grep shell/nav/div counts	Desktop Commander:start_process
PLAN	State changes + files + risks to Arun before touching anything	Text
EXECUTE	Single clean pass — never patch a broken patch	Python script via start_process
VERIFY LIVE	Browser screenshot of every changed page	Claude in Chrome
COMMIT	Only after live browser confirms page loads correctly	git add -A && push

NEVER claim done without browser screenshot. NEVER edit without reading full file structure first. NEVER patch a patch — restore from clean Downloads source if broken.

RULE 2 — REPEAT MISTAKES REGISTRY (NEVER REPEAT THESE)

#	Mistake	Correct Behaviour
1	Edit HTML without reading structure	grep shell/nav/div layout before any edit
2	Nav regex consuming closing shell div	Only replace nav tag contents — assert div count unchanged
3	Claim "fixed" without browser screenshot	Browser screenshot is the ONLY acceptable proof
4	Patching broken patches	Restore from clean Downloads source, patch minimally
5	Changing hero grid for ad slots	Add ads as position:fixed or outside grid — never change grid
6	window.claude.complete() on live site	Use mailto: or Supabase — claude.complete works in Claude artifacts only
7	Assuming all pages have same structure	Shell pages vs scroll pages — always check before editing
8	Using bash_tool for Mac filesystem	Container /mnt ≠ Mac — always use Desktop Commander for Mac
9	Not waiting for Vercel deploy before checking	Wait 15-20s then browser verify
10	Not counting divs after regex edit	Count shell open/close divs before AND after every regex
11	Multiple questions to Arun	Max ONE question
12	Saying "done" without browser screenshot	Screenshot = only proof. No screenshot = not done.
13	Re-doing tasks Arun confirmed with 👍	If Arun said 👍 — never touch it again
14	Long preamble before acting	Act first, brief explanation after
15	Adding new CSS without checking existing classes	grep existing CSS before writing new rules
16	Using display:grid on .diag-shell with flex:1	Use display:flex + explicit widths on children
17	Not overriding hm-design.css body padding on shell pages	Shell pages MUST override body padding-left/right:0!important
18	Leaving hm-sidebar-left/right visible on full-height pages	Add display:none!important on shell pages with own panels
19	system_design.html sending wrong fetch payload	Always send `{ messages: [{role,content}] }` — never `{ message, systemContext }`
20	XHR timeout 35s on Render backend	Render cold start = 50–70s — always set XHR timeout to 90s
21	No client-side keep-alive on chat pages	Every chat page MUST have 8-min XHR GET ping to backend root
22	Frontend/backend API contract drift after backend hardening	When validateChatRequest changes — audit ALL pages that call /api/chat
23	Not updating CLAUDE.md, SKILL.md, memory at session end	MANDATORY — Arun's standing rule — always update all three before closing
24	Circuit diagram magic number offsets for port connections	ALWAYS named coordinate constants — DCV_P_X, DCV_T_X, PMP_OUT_X etc. Never arithmetic
25	PRV body placed above pressure rail — vent wraps over top of diagram	PRV ALWAYS below rail. Inlet taps DOWN from rail to PRV_BOT. Drain exits PRV_TOP upward to return rail then tank
26	DCV P/T ports not on centre of middle box	DCV_P_X = dcvL + dvW + dvW/2. DCV_T_X = same X. Never use offset like +22
27	Diagonal flow lines in hydraulic circuit	ISO 1219 — ALL lines orthogonal only. Zero diagonal routing ever
28	No pre-push circuit checklist	Run full ISO 1219 checklist (see RULE 16 below) before every push
29	PRV inlet/drain reversed — inlet at top, drain at bottom	ISO 1219-1: INLET=BOTTOM (PRV_BOT). DRAIN=TOP (PRV_TOP). Spring on DRAIN side. Arrow points UP (inlet→drain)
30	Motor ports A & B both connecting to top of motor circle	Port A = LEFT side (MOT_X-mR). Port B = RIGHT side (MOT_X+mR). Never use RAIL_Y-mR for both
31	Return rail final drop offset from tank centre	Return rail must drop to TK_CX exactly — not TK_CX+offset
32	Writing circuit SVG code WITHOUT a topology grid plan first	MANDATORY: define the full grid table FIRST (all component centres, all port XY, all gap checks) BEFORE writing any SVG. Never generate coordinates mentally while coding
33	Claiming circuit correct without live browser screenshot	Screenshot = only proof. Never claim done without verifying in browser with zoomed audit

RULE 3 — PROJECT STATE (June 1, 2026)

Platform URLs

Service	URL
Frontend (live)	https://hydromindai.com
Backend	https://hydromind-backend.onrender.com
Backend API chat	https://hydromind-backend.onrender.com/api/chat
Supabase	frqefpoheewbornozvhc
Android App	https://play.google.com/store/apps/details?id=com.hydromind.app

Mac File Paths (EXACT — Jun 2026)

Item	Path
Web root	/Users/Apple/Documents/HydroMind-Website/Web
Backend root	/Users/Apple/Documents/HydroMind-Website/Backend
Android app	/Users/Apple/Documents/HydroMind-Platform/android-app
CSS design system	/Users/Apple/Documents/HydroMind-Website/Web/css/hm-design.css
Auth JS	/Users/Apple/Documents/HydroMind-Website/Web/js/auth.js
Session skill	/Users/Apple/Documents/HydroMind-Website/Web/skills/claude-session-skill/SKILL.md

Git Remotes

Repo	Remote
Frontend (Vercel)	arun25hyd/hydromind-ai
Backend (Render)	arun25hyd/hydromind-backend

Design System — v4.0 DARK TEAL THEME

Token	Value
Background	#080f14
Surface	#0d1720
Card	#111d2a
Accent	#06b6d4 (teal)
Accent bright	#22d3ee
Text primary	#e2f0f5
Text secondary	#7fb3c8
Success	#10b981
Warning	#f59e0b
Danger	#ef4444
Nav height	60px (--nav-h)
Sidebar width	140px (--sb-w)
Fonts	Inter + Space Mono + Syne 800
CSS file	css/hm-design.css v4.0 (923 lines)

Page Status — Web v2.0 Rebuild (updated June 05 2026)

Page	Status	Notes
hm-design.css	✅ DONE	Dark teal v4.0
auth.js	✅ DONE	Dark modal fixed
index.html	✅ DONE	Hero, stats, features, calc, app banner, QR
crane_diagnostic.html	✅ DONE	3-col, PLC bar, 8 cranes — chatHistory fix + 90s timeout + keep-alive added Jun 5
system_design.html	✅ DONE	fetch payload fixed (messages array), response parser fixed Jun 5
ai_advisor.html	⚠ VERIFY	var history clash fixed in earlier session — confirm keep-alive present
knowledge_base.html	⏳ PENDING	Needs audit
pricing.html	⏳ PENDING	Left sidebar grid fix needed
pages/feedback.html	⏳ PENDING	Left sidebar grid fix needed

Android App Status

Item	Value
Version	v1.0.39 (versionCode 43)
Next versionCode	44
Installs	6
Countries	177
Known issue	Deprecated edge-to-edge API (Expo SDK 54) — defer to SDK 55

Clean Source HTML Files in Downloads (RESTORE FROM HERE IF PAGE BROKEN)

Deployed name	Downloads source
index.html	HydroMind .html
ai_advisor.html	AI Advisor.html
crane_diagnostic.html	Crane Diagnostic.html
system_design.html	System Design .html
knowledge_base.html	Knowledge Base.html
pricing.html	Pricing (1).html

GOLDEN RULE: If a page is broken or blank — restore from Downloads source. Never patch a broken patch.

KB State (May 3, 2026)

KB1–KB47: OEM manuals
KB48: Fukushima IHI — PENDING
KB49–KB86: Hydraulic textbooks, crane standards, seals, wire rope, rigging
KB87: ISO 4413:1998 — Full hydraulic system safety rules
KB88: Rexroth VT-VRPA2 — Servo solenoid valve amplifier (RE 30048)
KB89: Rexroth VT-VRPA1 — Proportional valve analogue amplifier (RA 30118)
KB90: Palfinger PK10000 — Hydraulic knuckle boom crane operators manual
SKILL.md: updated May 3, 2026 | Next KB: KB91

RULE 4 — HTML PAGE STRUCTURES (CRITICAL — READ BEFORE EVERY EDIT)

SHELL LAYOUT pages — nav MUST be INSIDE the shell div:

ai_advisor.html
crane_diagnostic.html
system_design.html

Correct structure:

<body>
  <div class="bg-wrap"><canvas id="bgCanvas"></canvas></div>
  <div class="shell">              ← ALL content inside here
    <nav class="nav">...</nav>
    <div class="mobile-menu" id="mobileMenu OR mm">...</div>
    <div class="ticker">...</div>
    <div class="main">...</div>
  </div><!-- /shell -->            ← IF CONSUMED → PAGE GOES COMPLETELY BLANK
</body>

DANGER: crane_diagnostic.html uses id="mm" NOT id="mobileMenu". DANGER: If the closing

is eaten by regex → page shows only black particle background. VERIFY: After any edit grep for closing shell comment: grep "shell" filename.html

SCROLL LAYOUT pages — normal scroll, no shell:

index.html
knowledge_base.html
pricing.html
privacy.html
disclaimer.html

RULE 5 — SAFE NAV REPLACEMENT TEMPLATE (use this exactly)

import re

with open(fname, 'r') as f:
    html = f.read()

# Count BEFORE
shell_before = html.count('<div class="shell">')
mm_before = html.count('class="mobile-menu"') + html.count('id="mm"')

# Replace ONLY nav tag — narrow pattern, count=1
html = re.sub(r'<nav\b[^>]*>.*?</nav>', NEW_NAV_HTML, html, count=1, flags=re.DOTALL)

# ASSERT — if these fail, ABORT and restore from source
assert html.count('<div class="shell">') == shell_before, "SHELL BROKEN — ABORT"
assert (html.count('class="mobile-menu"') + html.count('id="mm"')) == mm_before, "MOBILE MENU BROKEN — ABORT"

with open(fname, 'w') as f:
    f.write(html)

RULE 6 — UNIFIED NAV HTML (same structure all pages — only class="active" changes)

<nav class="nav">
  <a class="nav-logo" href="index.html">
    <div class="nav-logo-icon">HM</div>
    <span class="nav-logo-text">HYDRO<b>MIND</b>.AI</span>
  </a>
  <div class="nav-links">
    <a href="index.html">Home</a>
    <a href="ai_advisor.html">AI Advisor</a>
    <a href="crane_diagnostic.html">Crane Diagnostic</a>
    <a href="system_design.html">System Design</a>
    <a href="knowledge_base.html">Knowledge Base</a>
    <a href="pricing.html">Pricing</a>
  </div>
  <div class="nav-r">
    <span class="badge badge-green"><span class="dot-pulse"></span> AI ONLINE</span>
    <button class="btn-login" onclick="openAuth('login')">Login</button>
    <button class="btn-pro" onclick="openAuth('register');selectPlan('pro')">Get Pro →</button>
  </div>
  <button class="nav-toggle" onclick="document.getElementById('mobileMenu').classList.toggle('open')">
    <span></span><span></span><span></span>
  </button>
</nav>

Active page link gets: class="active" Logo icon MUST show: HM — never H. or H or blank.

RULE 7 — DESIGN SYSTEM (May 1, 2026)

Token	Value
Primary orange	#FF6B1A / var(--o)
Orange 2	#FF9A4A / var(--o2)
Background	#080A0C / var(--bg)
Surface	#0D1014 / var(--bg2)
Card	#131820 / var(--bg3)
Border	rgba(255,255,255,0.07) / var(--b)
Text primary	#EEF0F4 / var(--t)
Text muted	#8A919E / var(--td)
Green	#34D399 / var(--green)
Blue	#60A5FA / var(--blue)
Font sans	Space Grotesk
Font mono	Space Mono

Active nav: color:var(--o); background:rgba(255,107,26,.12); font-weight:700 Gold and cyan: FULLY ELIMINATED — never reintroduce.

RULE 8 — SITE STATUS (May 1, 2026)

All 8 pages working live:

index.html ✅ — animated circuit v4.0
ai_advisor.html ✅ — full shell layout, chat working
crane_diagnostic.html ✅ — PLC sequence, instrument bar
system_design.html ✅ — 12-step wizard
knowledge_base.html ✅ — 45+ docs loading
pricing.html ✅ — feedback mailto:support@hydromindai.com
privacy.html ✅
disclaimer.html ✅

Pending items:

Ad slots hero (left/right) — safe implementation without touching grid
Ad slots KB (left/right) — same
Login → nav update post-auth — onclick wired, needs live confirm
/pages/* redirects — live in vercel.json

RULE 9 — ANDROID APP STATE

Item	Value
Package	com.hydromind.app
EAS account	arun25hyd
App path	/Users/admin/HydroMind-Platform/android-app
versionCode	35 (set on EAS remote)
Build	In progress — started May 1 08:32 AM
Build ID	a7521b1e-fb66-458c-bf09-5003dafb784f
Next step	Build complete → Internal Testing → Production

HydroFit (com.hydrofit.app): /Users/admin/hydrofit — EAS build deferred.

RULE 10 — GIT WORKFLOW (exact)

cd /Users/admin/Desktop/HydroMind-Platform/web-frontend
git branch           # MUST confirm main
git add -A
git commit -m "fix: description"
git push origin main
# Wait 20 seconds
# Open browser → screenshot every changed page
# Only then report done to Arun

RULE 11 — BROWSER VERIFICATION PROTOCOL (MANDATORY AFTER EVERY PUSH)

1. Claude in Chrome: list_connected_browsers → select_browser → tabs_context_mcp
2. navigate to EVERY changed page URL
3. wait 4-5 seconds per page
4. screenshot — check ALL of:
   ✓ Nav bar visible at top
   ✓ Correct page active in orange
   ✓ Logo shows HM
   ✓ Page content visible — NOT blank dark screen
   ✓ No layout broken
5. If blank → check shell div, restore from source
6. ONLY after all pages pass → report done to Arun

RULE 12 — TOOL SELECTION

Task	Correct Tool
Read file on Mac	Desktop Commander:read_file
Run command on Mac	Desktop Commander:start_process
Edit file on Mac	Desktop Commander:start_process (Python)
Browse live site	Claude in Chrome
Read uploaded file	view /mnt/user-data/uploads/
Run bash in container	bash_tool

Container /mnt ≠ Mac filesystem. NEVER confuse them.

RULE 16 — HYDRAULIC CIRCUIT DIAGRAM STANDARDS (MANDATORY)

HydroMind AI is tested by real offshore hydraulic engineers and field designers. A wrong symbol, reversed port, or broken connection destroys platform credibility instantly.

══ CRITICAL DCV PORT RULE — THE MOST REPEATED MISTAKE ══

ALL FOUR ports (P, T, A, B) connect to the CENTRE box only. A and B are TOP. P and T are BOTTOM.

     A    B        ← TOP of symbol  (work ports → actuator)
     |    |
 ┌───┼────┼───┐
 │ ↑↓│ XX │↑↓ │   3 boxes: extend | neutral(blocked) | retract
 └───┼────┼───┘
     |    |
     P    T        ← BOTTOM of symbol (P=pump inlet, T=tank return)

Left/right boxes = spool positions only. NO pipes connect to outer boxes.

DCV must sit ABOVE the pressure rail:

dcvB = Y_RAIL = 290   (DCV bottom edge = pressure rail level)
dcvT = dcvB - dvH     (DCV top edge = 240)
P port at (DCV_P_X, dcvB) — pressure rail arrives here directly
T port at (DCV_T_X+6, dcvB) — exits bottom, stub goes down to return rail
A port at (DCV_A_X, dcvT) — exits top, bypass channel goes UP to actuator
B port at (DCV_B_X, dcvT) — exits top, bypass channel goes UP to actuator

══ LOAD SENSING (LS) PILOT LINE RULE ══

LS pilot taps from DCV A-port work line — NOT from the actuator/cylinder.

WRONG: LS line from cylinder/motor back to pump
RIGHT: LS line from DCV A work port (bypY_A channel) back to pump compensator

Per ISO 4413: the LS signal is the highest load pressure signal,
taken from the DCV work port, fed back to the pump displacement control.

Code:
  pilY = bypY_A - 16   (16px above A bypass channel, clear of it)
  Path: DCV_A_X,bypY_A → DCV_A_X,pilY → PUMP_X,pilY → PUMP_X,PUMP_Y+P_R
  Label: "LS" near DCV end, "PUMP COMPENSATOR" near pump end

BEFORE writing a single line of SVG code, you MUST define the full coordinate grid.

This is the lesson from 6+ failed circuit iterations on June 05 2026. Every single failure was caused by generating coordinates mentally while writing code. Fixing one value broke another. The grid-first approach eliminates this entire class of error.

THE MANDATORY PROCESS — no exceptions:

STEP 1: Define full grid table (copy-paste this template, fill in values)
────────────────────────────────────────────────────────────────
Canvas:    W=1100, H=660
RAILS:     Y_RAIL=290  Y_RET=470  Y_SUCT=350
TANK:      TK_CX=70    TK_TOP=540  TK_HALF=36
PUMP:      PUMP_X=190  PUMP_Y=290  P_R=22    PMP_IN=168   PMP_OUT=212
FILTER:    FILT_X=320  FILT_Y=290  F_R=14    FLT_IN=306   FLT_OUT=334
PRV:       PRV_X=420   PRV_CY=410  PRV_SZ=20 PRV_BOT=430  PRV_TOP=400  PRV_SPR=378
GAUGE:     GAU_X=380   GAU_Y=210   G_R=10
DCV:       dcvL=485 dcvR=635 dcvT=265 dcvB=315 DCV_X=560  dvW=50 dvH=50
           DCV_P_X=560  DCV_T_X=560  DCV_A_X=485  DCV_B_X=635
           DCV_P_Y=265  DCV_T_Y=315
BYPASS:    bypY_A=233   bypY_B=213   (A=32px above dcvT, B=52px above dcvT)
CYLINDER:  cyX=780 cyY=268 cyW=90 cyH=44  pisX=818
           CYL_A_X=790  CYL_A_Y=268  CYL_B_X=818  CYL_B_Y=268
MOTOR:     MOT_X=830  MOT_Y=290  M_R=24  MOT_L=806  MOT_R=854
COOLER:    coolX=240  coolY=470  coolW=40 coolH=28
RTN FILT:  rfX=150    rfY=470    rfR=12
ACCUM:     ACCUM_X=700  ACCUM_Y=200  ACC_R=16

STEP 2: Collision check BEFORE writing SVG (minimum 60px gap between components)
────────────────────────────────────────────────────────────────
Pump right (PMP_OUT=212) → Filter left (FLT_IN=306):     gap=94  ✓
Filter right (FLT_OUT=334) → PRV centre (PRV_X=420):     gap=86  ✓
PRV centre (420) → DCV left edge (dcvL=485):              gap=65  ✓
DCV right edge (dcvR=635) → Cylinder left (cyX=780):      gap=145 ✓
bypY_A (233) vs DCV top (dcvT=265):                       gap=32  ✓
bypY_B (213) vs bypY_A (233):                             gap=20  ✓
PRV_TOP (400) vs Y_RAIL (290):                            gap=110 ✓  (PRV is BELOW rail)
PRV_BOT (430) vs Y_RET (470):                             gap=40  ✓

STEP 3: Only now write the SVG code — all values from grid, no inline arithmetic
────────────────────────────────────────────────────────────────

ISO 1219-1:2012 SYMBOL REFERENCE

Component	ISO Correct Symbol	NEVER Do This
Fixed pump	Circle + solid triangle, apex pointing RIGHT (outlet)	Triangle wrong direction, outside circle, or text only
Variable pump	Fixed pump + diagonal arrow through circle	Writing "VAR" as text label only
Hydraulic motor	Circle + triangle apex pointing INTO circle from RIGHT	Letter "M" inside circle, or same symbol as pump
Double-acting cylinder	Rect + thick end-caps BOTH sides + piston line at 42% + rod exits ONE side only	Rod both sides, no end caps, wrong piston position
HP/Return filter	Circle with diagonal hatching lines INSIDE (needs clipPath)	Striped rectangle
PRV	Square body + arrow UP inside + spring zigzag ABOVE box + fixed seat line	Rotated diamond, arrow wrong direction, spring below box
4/3 DCV	THREE separate equal adjacent squares + internal flow arrows + solenoid hatched rects + spring triangles	Single rect with dividers
Accumulator	Circle bisected by horizontal line — gas top (N₂), fluid bottom	Plain ellipse or circle
Cooler / HE	Rectangle with X pattern inside	Rectangle with plus or empty
Reservoir	Two horizontal parallel lines + vertical end caps both sides	Filled rectangle
T-junction dot	Filled circle r=3.5 at EVERY branch point on pressure/return rails	Missing — engineers expect and look for junction dots

MANDATORY NAMED PORT CONSTANTS

Every single port position MUST be declared as a named variable from the grid. NEVER calculate port positions inline inside flow line path strings.

// PRESSURE RAIL PORTS
PMP_IN  = PUMP_X - P_R    // pump inlet  = left  of circle
PMP_OUT = PUMP_X + P_R    // pump outlet = right of circle
FLT_IN  = FILT_X - F_R   // filter inlet
FLT_OUT = FILT_X + F_R   // filter outlet

// DCV PORTS — all derived from dcvL, dvW
DCV_P_X = dcvL + dvW + dvW/2  // = dcvL+75 = exact centre of middle box TOP
DCV_T_X = DCV_P_X             // same X — centre of middle box BOTTOM
DCV_A_X = dcvL                // left  edge of left  box (A port)
DCV_B_X = dcvR                // right edge of right box (B port)
DCV_P_Y = dcvT                // top  of DCV boxes
DCV_T_Y = dcvB                // bottom of DCV boxes

// PRV PORTS — INLET=BOTTOM, DRAIN=TOP
PRV_BOT = PRV_CY + PRV_SZ/2  // INLET: pressure rail taps DOWN to this point
PRV_TOP = PRV_CY - PRV_SZ/2  // DRAIN: exits upward through spring to return/tank
PRV_SPR = PRV_TOP - 22        // top of spring zigzag / fixed seat line

// ACTUATOR PORTS
CYL_A_X = cyX + 10           // cylinder: cap-end port (left area)
CYL_A_Y = cyY                 // top of barrel
CYL_B_X = cyX + cyW*0.42     // cylinder: rod-side port (piston position)
CYL_B_Y = cyY                 // top of barrel
MOT_L   = MOT_X - M_R        // motor port A: LEFT  side of circle
MOT_R   = MOT_X + M_R        // motor port B: RIGHT side of circle

CIRCUIT TOPOLOGY (ISO 4413)

PRESSURE PATH (solid line, 2px):
  Tank (TK_CX,TK_TOP) → up to Y_SUCT → horizontal to PMP_IN → up to Y_RAIL
  PMP_OUT → [gauge tap at GAU_X] → [PRV tap at PRV_X] → DCV_P_X (horizontal)
  DCV_P_X,Y_RAIL → DCV_P_X,DCV_P_Y (vertical stub down into P port)

PRV BRANCH (red dashed, 1.2px):
  PRV_X,Y_RAIL → PRV_X,PRV_BOT     (inlet: rail taps VERTICALLY DOWN)
  PRV_X,PRV_TOP → PRV_X,Y_RET      (drain: exits VERTICALLY DOWN from box top)
  PRV_X,Y_RET → TK_CX,Y_RET        (horizontal left along return rail)
  TK_CX,Y_RET → TK_CX,TK_TOP       (vertical down to tank)
  Junction dot at PRV_X,Y_RET

WORK LINES A and B (via bypass channels ABOVE DCV assembly):
  A (pressure, 1.8px): DCV_A_X,Y_RAIL → DCV_A_X,bypY_A → port_A_X,bypY_A → port_A_X,port_A_Y
  B (return,  1.5px): DCV_B_X,Y_RAIL → DCV_B_X,bypY_B → port_B_X,bypY_B → port_B_X,port_B_Y
  Cylinder: port_A=(CYL_A_X,CYL_A_Y)  port_B=(CYL_B_X,CYL_B_Y)
  Motor:    port_A=(MOT_L,MOT_Y)       port_B=(MOT_R,MOT_Y)

DCV T PORT → RETURN RAIL (solid, 1.5px):
  DCV_T_X,DCV_T_Y → DCV_T_X,Y_RET (straight vertical down)
  Junction dot at DCV_T_X,Y_RET

RETURN RAIL (solid, 1.5px, darker teal):
  DCV_T_X,Y_RET → cooler_right → cooler_left → rf_right → rf_left → TK_CX,Y_RET → TK_CX,TK_TOP
  Junction dot at TK_CX,Y_RET

BYPASS CHANNEL RULES (A and B lines above DCV)

bypY_A = dcvT - 32    // 32px clear above DCV top — no component within ±20px
bypY_B = dcvT - 52    // 52px above, 20px above bypY_A — two distinct channels
Both channels must have clear horizontal run from DCV port X to actuator port X.
No solenoid box, no label, no other component crosses these channels.

COMPLETE PRE-PUSH CHECKLIST (run BEFORE every circuit push, no exceptions)

GRID CHECK:
□ Full grid table defined with all component centres and port positions
□ Collision check run — all gaps ≥ 60px confirmed
□ No port positions calculated inline — all from named constants

SYMBOL CHECK (ISO 1219-1):
□ Pump:      circle + triangle apex RIGHT (outlet direction)
□ Motor:     circle + triangle apex INTO circle from RIGHT (opposite pump)
□ Filter:    circle with diagonal hatching inside (clipPath used)
□ PRV:       square body + arrow UP inside + spring zigzag ABOVE box + fixed seat
□ PRV inlet: BOTTOM of box (PRV_BOT) — pressure taps DOWN from rail
□ PRV drain: TOP of box (PRV_TOP) — exits upward through spring to return/tank
□ DCV:       THREE separate equal boxes side by side (not one box with dividers)
□ DCV P:     enters top-centre of middle box = DCV_P_X = DCV_X
□ DCV T:     exits bottom-centre of middle box = DCV_T_X = DCV_P_X (same X)
□ DCV A:     exits left edge of left box = DCV_A_X = dcvL
□ DCV B:     exits right edge of right box = DCV_B_X = dcvR
□ Cylinder:  thick end-caps both sides, piston line, rod exits ONE side only
□ Cylinder A port: cap-end top stub (left of piston)
□ Cylinder B port: rod-end top stub (right of piston)
□ Motor A port: LEFT side of motor circle = MOT_L = MOT_X - M_R
□ Motor B port: RIGHT side of motor circle = MOT_R = MOT_X + M_R
□ Accumulator: circle bisected by horizontal line (gas top, fluid bottom)
□ Reservoir: two parallel lines + end caps (not filled rectangle)
□ Junction dots: at EVERY T-branch on pressure rail, return rail, PRV drain

LINE CHECK:
□ ALL flow lines orthogonal — zero diagonal lines
□ Suction line routes via Y_SUCT offset (not through pump body)
□ Bypass A and B have clear separate channels above DCV (bypY_A, bypY_B)
□ No line passes through any component body
□ Return rail drops to TK_CX exactly (not TK_CX+offset)
□ PRV drain AND return rail share Y_RET with junction dot
□ Component reference table present (top-right)
□ Legend with line types present (bottom)
□ ISO 1219-1 disclaimer in footer
□ Canvas W ≥ 1100

BROWSER VERIFICATION (MANDATORY — no exceptions):
□ Deployed to Vercel and hard-refreshed
□ Screenshot taken of full circuit
□ Each section zoomed and compared against this checklist
□ Only after all 26+ points confirmed = circuit is done

RULE 17 — HYDRAULIC TROUBLESHOOTING PROTOCOL

Identify: System type → Architecture → Suspect component
Check: KB entry for that model first (KB01–KB86)
Diagnose: Pressure → Flow → Temperature → Case drain
Isolate: Upstream vs downstream of suspect
Test: Specific gauge points or signal measurements
Conclude: Root cause + corrective action + parts list

Architecture types:

Closed loop hydraulic: pilot joystick → pump swash direct, no electronics
Electronic closed loop: PLC → amplifier → prop valve → swash → motor A/B, brake DCV
Open loop pilot DCV: constant flow pump → DCV → motor/cylinder → tank, CBVs at 110-130% load

OEM tools: Liebherr=LiDAT | Rexroth=BODAS | Danfoss=PLUS+1 | Eaton=gauges only

RULE 14 — COMMUNICATION STYLE

👍 from Arun = task complete — NEVER redo it
Arun corrects directly — accept immediately, no defence, no excuses
Short responses unless code/tables required
Lead with action, not preamble
ONE question max per response
Engineering tone: precise, direct, no waffle
Never say "done" without browser screenshot proof

RULE 15 — SELF-CHECK BEFORE EVERY EDIT

Before touching any file answer all these:

Read full file structure (not just target lines)?
Counted shell div open/close?
Using clean source or patching broken patch?
Will verify live in browser before reporting done?
Correct tool: Mac=Desktop Commander, Container=bash_tool?
Regex narrow enough — not consuming surrounding divs?

If ANY is NO — stop and fix first.

Version Control

Version	Date	Changes
v1.0	2026-04-04	Initial
v2.0	2026-04-19	KB71-86, hero v2, advisor 8 modes, Android versionCode 35
v3.0	2026-05-01	CRITICAL UPDATE: shell layout rules, safe nav template, browser verify mandatory, May 1 site state, full mistake registry from today's failures
v3.1	2026-05-03	KB87–KB90 added: ISO 4413, Rexroth VT-VRPA2, VT-VRPA1, Palfinger PK10000
v4.0	2026-06-01	Full redesign to dark teal v4.0, new page structure rules, sidebar rules
v4.1	2026-06-05	Added mistakes #19–23. Page status table updated.
v4.2	2026-06-05	Added RULE 16 — full hydraulic circuit diagram standards. ISO symbols, named port constants, topology rules, pre-push checklist. Mistakes #24–28.
v4.3	2026-06-05	CRITICAL UPDATE: RULE 16 completely rewritten with GRID-FIRST LAW. Full verified grid template (W=1100, all 13 named port constants, collision check table). Complete 30-point pre-push checklist including grid check + symbol check + line check + browser verification. Mistakes #29–33 added. Root cause of all circuit failures: writing SVG without topology grid first. This is now fixed permanently.

KB87 — ISO 4413:1998 — Hydraulic Fluid Power General Rules

Document: ISO 4413:1998 (Second Edition) — Hydraulic fluid power — General rules relating to systems Category: Standards & Compliance Scope: All hydraulic systems on industrial and marine machinery

Key Requirements by Section

Safety (Clause 4):

All parts of system must be protected against pressures exceeding maximum working pressure
Primary protection = pressure relief valves; alternative = pressure compensator pump controls
Surge and intensified pressures must not cause hazards
Loss of pressure or critical pressure drop must not expose persons to hazard
Mechanical movements (intended or unintended) must not create hazardous situations

System Design (Clause 5):

Circuit diagrams must comply with ISO 1219-2
Circuit diagram must include: all component IDs, pipe/tube sizes, cylinder bore/rod/stroke, motor displacement/torque, pump flow/direction, pressure settings, filter types, fluid volume, fluid type/viscosity, accumulator pre-charge pressures
All ports, test points, bleed points and drain outlets must be clearly identified
Components >15 kg must have lifting provisions
Installation height: bottom edge min 0.6 m, top edge max 1.8 m above working platform

Pumps & Motors (Clause 6.1):

Must be mounted accessible for maintenance with no shaft misalignment under duty cycle
Drive couplings must withstand maximum torque under all operating conditions
Case drain lines must meet OEM specification — no excessive back pressure
Pump inlet pressure must not be less than minimum specified by pump supplier
Tapered pipe threads or sealing compounds NOT permitted on connections

Cylinders (Clause 6.2):

Piston rod material must minimise wear, corrosion and impact damage (HVOF or hard chrome standard)
Pressure intensification from piston area differences must be prevented by circuit design
Cylinders used as position stops must be sized for maximum incurred loading
Port location: cylinders installed with ports uppermost where practical

Accumulators (Clause 6.3):

Must auto-vent liquid pressure or positively isolate when system shuts off
Warning label mandatory: "CAUTION – System contains accumulator(s). Depressurise before maintenance"
Charging medium: nitrogen only — never oxygen or air
Fully depressurise both liquid AND gas sides before disassembly

Valves (Clause 7):

Surface-mounted and cartridge valves preferred
Manifold mounting surfaces per ISO 4401, ISO 5781, ISO 6263, ISO 6264, ISO 7790
Electrically operated valves: solenoids must operate reliably at nominal voltage ±10%
Manual override mandatory if valve must operate when electrical control unavailable
Valves that can cause hazard if adjusted must be tamper-proof

Fluid & Conditioning (Clause 8):

Reservoir minimum height: 150 mm above floor level
Reservoir must dissipate heat under normal working without heat exchanger if applicable
Return lines must discharge below minimum operating fluid level at lowest practical velocity
Filtration must limit contamination per ISO 4406
Suction filtration NOT recommended unless agreed supplier/purchaser
Filter assemblies must have differential pressure indicator visible to operator
Heat exchangers: cooling media control valves on input line; shut-off valves in cooling medium lines for maintenance

Piping (Clause 9):

Fluid velocity limits: suction lines ≤1.2 m/s | pressure lines ≤5 m/s | return lines ≤4 m/s
Pipe support spacing: OD <10mm = 1m | 10-25mm = 1.5m | 25-50mm = 2m | >50mm = 3m
Hose assemblies must not be bent below minimum bending radius
Quick-action couplings must auto-seal both sides on disconnection

Control Systems (Clause 10):

Servo/proportional valve supply line: full-flow filter WITHOUT bypass, collapse strength > system max pressure
System must be cleaned to stabilised contamination level BEFORE servo/proportional valves installed
Emergency stop must not itself cause a hazard
At least one emergency stop must be remotely located
Spring-biased or detent-located valves mandatory for any actuator that must hold position on control failure

Commissioning (Clause 14):

No measurable unintended leakage permitted (slight wetting not forming a drop is acceptable)
Pressure test each part at maximum pressure that may be sustained under all conditions of intended use

Pressure Test Points

Permanently installed gauges must be protected by pressure limiter or gauge isolator
Gauge range upper limit must exceed max working pressure by minimum 25%
Fluid sampling point per ISO 4021 must be provided for contamination monitoring

Standards Referenced

ISO 1219-1, ISO 1219-2, ISO 4401, ISO 4406, ISO 4021, ISO 6149, ISO 6162, ISO 6164, ISO 10763, IEC 204-1, IEC 529

KB88 — Rexroth VT-VRPA2 — Electric Amplifier for Servo Solenoid Valves (RE 30048/01.09)

Document: Bosch Rexroth RE 30048/01.09 — Electric Amplifiers Type VT-VRPA2, Unit Series 1X Manufacturer: Bosch Rexroth AG, Lohr am Main, Germany Category: Proportional/Servo Amplifier Cards Application: Direct actuation of servo solenoid valves type 4WRP Series 1X (offshore crane directional control)

Identification

Model: VT-VRPA2-1X
Format: Eurocard, 19" rack mount, DIN 41612-F32 connector
Unit series: 1X (10 to 19)
Serial numbers: 527 = NG6 | 537 = NG10

Technical Specifications

Parameter	NG6 (527)	NG10 (537)
Solenoid current	2.7 A	3.7 A
Solenoid voltage	25 V	50 V
Current rating	1.5 A	2.5 A
Power consumption	35 W	60 W
PCB dimensions	100 x 160 x ~35 mm	same
Weight	0.25 kg	0.25 kg
Ambient temp	0 to +70°C	same
Storage temp	-20 to +70°C	same

Power Supply:

24 VDC nominal
Battery: 21–40 V DC
Rectified AC: Ueff = 21–28 V (single-phase full-wave)
Smoothing capacitor: 4,700 µF/63 VDC (if UB ripple >10%)

Input Signal (Setpoint):

0 to ±10 V (Ri = 10 kΩ)
Potentiometer: 1 kΩ, ±10 V supply from card

Actual Value Feedback:

Oscillator frequency: 10.2 Veff / 7.8 kHz
Feedback signal: 0 to ±10 V DC
Open-circuit detection active — fault signal on cable break

Solenoid Cable:

Up to 20 m → 1.5 mm²
20 to 50 m → 2.5 mm²
Position transducer: max 50 m at 100 pF/m

Front Panel Adjustments (Trimming Potentiometers)

Pot	Function	Range
NPA / NPB	Valve zero adjustment	±10% of stroke
QA / QB	Sensitivity	100% to 50%
Ramp α	Acceleration ramp time	0.05 to 5 seconds
Ramp β	Deceleration ramp time	0.05 to 5 seconds

LED Indicators

LED	Colour	Meaning
Enable	Green	Enable ON — output stage active
UB low	Red	Supply voltage below 21 V
Ramp OFF	Yellow	Ramp function deactivated
Open circuit	Yellow	Feedback signal cable break detected

Enable & Ramp Logic

Enable input: z16, U = 8.5–40 V → output stage active
Ramp OFF: b20 linked to b22 or 8.5–40 V at b20 → immediate transition (no ramp)
Ramp ON: b20 open (default)
Ramp OFF, Enable OFF, or Open Circuit = abrupt transition to final signal value

Key Functions

Deadband Compensation: Electronic bypass of ±20% spool overlap in ±15% range — prevents dead zone response at valve centre Quadrant Recognition: Ramp switches automatically when valve spool crosses centre to maintain equal acceleration in both directions Zero Compensation: Input 0.3–0.5 V required to exit deadband correctly Closed-loop Position Control: PID action on spool position via LVDT feedback Clocked Output Stage: Fast energise/de-energise for rapid response

Fault Signals (Open Collector to +UK, max 100 mA)

Feedback signal open circuit
UB too low
±15 V internal stabilisation fault

Wiring Notes

Power zero (b2) and control zero (b12) must be connected SEPARATELY to central ground (neutral point)
Never connect power zero and control zero together — causes ground loops
Test box: VT-PE-TB1 (RE 30063)
Test adapter: VT-PA-3 (RE 30070)

Fault Diagnosis — Field Guide

Symptom	Likely Cause	Check
No valve movement	Enable not active	Confirm z16 = 8.5–40V
Red LED on	Supply <21V	Check UB at b16/b18
Yellow open-circuit LED	LVDT cable break	Check transducer cable continuity
Valve hunting/oscillating	PID gain too high	Reduce sensitivity QA/QB
No ramp on start	Ramp disabled	Check b20 — must be open for ramp ON
Valve stuck at one side	Zero offset	Adjust NPA or NPB trimmer

KB89 — Rexroth VT-VRPA1 — Analogue Amplifier for Proportional Valves (RA 30118/11.04)

Document: Bosch Rexroth RA 30118/11.04 — Analogue Amplifier Model VT-VRPA1, Component Series 1X Manufacturer: Bosch Rexroth Corp., Bethlehem PA USA Category: Proportional Amplifier Cards Application: Proportional pressure control valves (DBETR), proportional flow control valves (2FRE 6/10/16)

Model Variants

Model	Valve Type	Solenoid R(20)	Mat. No.
VT-VRPA1-100-1X/V0/0	DBETR pressure valve	10 Ω	R901009038
VT-VRPA1-150-1X/V0/0	2FRE 6 flow valve	5.4 Ω	R901057058
VT-VRPA1-151-1X/V0/0	2FRE 10/16 flow valve	10 Ω	R901057060

Technical Specifications

Parameter	Value
Operating voltage	24 VDC (+40% / -5%)
Functional range	22–35 V
Power consumption	<35 W
Current consumption	<1.5 A
Fuse	2.5 A T (slow blow)
PCB format	Eurocard 100 x 160 mm (DIN 41494)
Front plate	3HE x 4TE (3HE = 128.4 mm)
Connector	32-pin blade DIN EN 60603-2 form D
Ambient temp	0 to +50°C
Storage temp	-25 to +70°C
Weight	0.15 kg

Command Value Inputs

Input	Signal	Reference
Command value 1	0 to +9 V	M0 (measurement zero)
Command value 2	0 to +6 V	M0
Command value 3 (diff)	0 to +10 V / 0-20 mA / 4-20 mA	Differential

Internal regulated supply: ±9 V (raised zero point) — 25 mA external load available

Ramp Generator

Separate ramp times for UP (t1) and DOWN (t2) — adjusted via front panel potentiometers
Ramp time range: Short (X9 bridge) = 0.02 to 5 s | Long (X8 bridge) = 0.2 to 50 s
Ramp OFF: apply >10 V to switched input OR set bridge X4 → minimum ramp ~15 ms
Measurement sockets t1/t2 on front panel allow ramp time verification with voltmeter

Ramp time calculation:

Short: t_up = 1/Ut1 (seconds) | Long: t_up = 0.1/Ut1 (seconds)
Ut1 voltage at measurement socket — range -0.02 V (max time) to -5 V (min time)

Output Stage

Solenoid output: max 2.2 A ±10%
Clock frequency: free clocking ~1.5 kHz
Limiter: command value clamped to +105% / -5% — prevents spool hitting mechanical stop

Position Controller

PID controller optimised for DBETR and 2FRE valves
Inductive position transducer (LVDT) — oscillator frequency 2.5 kHz ±10%
Actual value output: 0 to -6 V (inverted vs command value — 100% travel = -6 V at socket x)

Plug-In Bridge Settings

Bridge	Function	Fitted	Open
X3	Enable	Permanently ON	External control
X4	Ramp	Permanently OFF	External control
X8	Long ramp (0.2–50s)	Long	—
X9	Short ramp (0.02–5s)	Short	—
X12-X14	Current input config	4-20 mA / 0-20 mA	Voltage

Enable Input

Active: >10 V at 20a → output stage released (yellow LED ON)
Not active: <9 V → output stage blocked
Bridge X3 = permanently enable ON (for replacing VT 5003/5004/5010)

Compatibility — Drop-in Replacement

Replaces amplifier types: VT 5003, VT 5004, VT 5010 When replacing: set bridge X3 (enable) to "permanently ON" — order 4TE/3HE dummy plate separately (mat. no. R900021004)

Wiring Critical Notes

Measuring zero (M0) is raised +9 V above 0 V operating voltage — NEVER connect M0 to 0 V (L0)
Always screen command value lines — screen to card-side 0 V, leave far end open (prevent earth loops)
Solenoid cables: LiYCY 1.5 mm² up to 50 m
Do not use solenoid plugs with freewheeling diodes or LED displays
Measurement instruments must have Ri >100 kΩ
Distance from antenna, radio and radar equipment: minimum 1 m
Do not lay solenoid and signal lines near power lines

Fault Diagnosis — Field Guide

Symptom	Likely Cause	Check
Green LED off	UB <20V or internal fault	Check supply, check ±9V rails
Yellow LED off	Enable not active	Check 20a > 10V or set X3
No valve response	Command value zero or zero pot wrong	Check Zw potentiometer
Valve at full stroke always	Limiter tripped	Check Zw and Gw settings
Unstable/oscillating	PID overshoot	Reduce Gw sensitivity
Ramp not working	Bridge X4 fitted	Remove X4 for external ramp control
Incorrect ramp direction	Wrong ramp bridge	Check X8 vs X9 — only one should be fitted

KB90 — Palfinger PK10000 — Hydraulic Knuckle Boom Crane

Document: Operators Manual — Hydraulic Crane PK10000 (Scribd ref: 492675723) Manufacturer: Palfinger AG, Austria Category: Offshore / Marine Knuckle Boom Crane Architecture: Open-loop hydraulic, knuckle boom (articulated jib), truck/deck mount

Crane Overview

The Palfinger PK10000 is a hydraulic knuckle boom loader crane used on deck vessels, supply boats and onshore heavy transport applications. It features a two-section articulated boom (main boom + knuckle/inner boom) driven by double-acting hydraulic cylinders with counterbalance valve protection on all load-holding circuits.

Note: Source PDF is scanned image format — specifications below are based on PK10000 series engineering data from Palfinger technical literature and field knowledge. Verify against OEM manual pages for exact serial-specific settings.

Typical Hydraulic Architecture

System type: Open-loop, load-sensing or fixed-displacement pump
Working pressure: 250–350 bar (system dependent)
Relief valve setting: 350 bar (system relief) | 380–400 bar (overload protection)
Hydraulic actuators: Double-acting cylinders (main lift, knuckle, extension)
Control: Hydraulic pilot joystick or radio remote — proportional DCVs
CBV protection: Counterbalance valves on all cylinder ports — set at 1.3× load-induced pressure

Main Hydraulic Circuits

Main Boom Lift (Kolben/Arm Cylinder):

Double-acting cylinder, clevis-mounted
Counterbalance valve (CBV) on rod side — prevents uncontrolled lowering
CBV pilot ratio: typically 3:1 to 4.5:1
Load holding: CBV closes on pilot pressure loss → crane holds load

Knuckle Boom (Inner Jib Cylinder):

Double-acting cylinder controlling articulation angle
CBV on both ports — bidirectional load holding
Critical: both CBVs must be set correctly to prevent knuckle collapse

Extension (Telescopic, if fitted):

Single or tandem cylinder extending inner boom
Mechanical lock or CBV depending on series

Slew (Rotation):

Hydraulic motor or ring gear cylinder arrangement
Crossover relief valves: 270–300 bar to absorb slew shock loads

Key Pressure Settings (PK10000 series typical)

Function	Setting
System relief	350 bar
Overload protection	380–400 bar
Main boom CBV	1.3 × max load-induced pressure
Knuckle CBV	1.3 × max load-induced pressure
Slew crossover relief	270–300 bar
Pilot supply pressure	30–40 bar

Common Fault Diagnosis

Fault	Cause	Action
Boom drifts down slowly	CBV internal leakage or wrong pilot ratio	Replace CBV or check pilot line pressure
Knuckle drops suddenly	CBV not opening — pilot line blocked	Check pilot line filter and orifice
No boom movement	System pressure low or pump fault	Check system relief, pump output
Slow operation	Flow insufficient or control valve restriction	Check pump RPM, DCV spool condition
Crane chatters under load	CBV set too low — opens/closes rapidly	Increase CBV setting by 10–15 bar
Slew shock/jerk	Crossover relief set too high or too low	Adjust crossover relief to 270–300 bar
Oil overheating	Unloading not working or cooler blocked	Check unload valve, clean cooler

Maintenance Schedule

Daily: Check oil level, inspect hoses and fittings for leaks, test emergency lowering
Weekly: Check CBV pilot lines, test overload protection
Monthly: Check all pressure settings with calibrated gauge, inspect cylinder seals
Annual: Full hydraulic oil change, filter replacement, CBV bench test

Safety Features

Overload protection system (OPS) — prevents lift beyond rated capacity
Emergency lowering — gravity or hand pump to lower load on power failure
Slew lock — mechanical or hydraulic slew brake
DNV/BV class notation available for offshore variants

Install via CLI

npx skills add https://github.com/arun25hyd/hydromind-ai --skill session-skill

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