Calculations

Calculations

• What a wire end connects to

  Joins a wire end to other wire ends, to pins and to the middle of other wires that it touches.

  connected when distance² ≤ tol², tol = 0.05

  Schematic wires, pins and connections addons/electrical/lib/wires.js

  • CadCraft
  64-bit

• Where a wire number goes

  The middle and direction of the longest segment of a net, for its wire number.

  x = (aₓ + bₓ) ÷ 2; y = (a_y + b_y) ÷ 2; rot = atan2(Δy, Δx) turned into (−π ÷ 2, π ÷ 2]

  Schematic wires, pins and connections addons/electrical/lib/wires.js

  • CadCraft
  64-bit

• Which wire a wire number belongs to

  Assigns each wire number to the nearest wire within reach.

  nearest segment with d² ≤ 3²

  Schematic wires, pins and connections addons/electrical/lib/wires.js

  • CadCraft
  64-bit

• Junction dots

  Places a dot at each junction and removes dots that no longer mark one.

  a dot marks a junction when d² ≤ max(tol, 0.2)²

  Schematic wires, pins and connections addons/electrical/lib/wires.js

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• Transform of a placed symbol

  The matrix that takes a symbol's own coordinates to the drawing.

  a = cos r × sx; b = sin r × sx; c = −sin r × sy; d = cos r × sy; e = x − (a bₓ + c b_y); f = y − (b bₓ + d b_y)

  Schematic wires, pins and connections addons/electrical/lib/symbols.js

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• A point through the transform

  Applies a symbol's matrix to a point.

  x′ = a x + c y + e; y′ = b x + d y + f

  Schematic wires, pins and connections addons/electrical/lib/symbols.js

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• Pin positions of a placed symbol

  The drawing positions of a symbol's connection points.

  Schematic wires, pins and connections addons/electrical/lib/symbols.js

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• Pin offsets written to the block

  Formats a pin offset for the block's EL attribute text.

  text = round(n × 1000) ÷ 1000

  Schematic wires, pins and connections addons/electrical/lib/symbols.js

  • CadCraft
  64-bit

• Attribute text kept upright

  Decides which attribute texts of a rotated symbol would read upside down and turns them half round.

  turn when cos(rot + text rot) ≤ −1e-9

  Schematic wires, pins and connections addons/electrical/lib/symbols.js

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  64-bit

• Sheet points on the 2.5 mm grid

  Moves a picked point on a sheet to the nearest point of the 2.5 mm grid.

  x = round(x ÷ 2.5) × 2.5

  Schematic wires, pins and connections addons/electrical/main.js

  • CadCraft
  Exact

• A wire point landing on a pin or wire

  Moves a picked wire point onto a pin, a wire end or a wire when it is within 2 units of one.

  candidate when d² ≤ 2²; a wire's middle is ranked with d² + 0.25

  Schematic wires, pins and connections addons/electrical/main.js

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  64-bit

• A wire cut under a new symbol

  Cuts a wire between two pins of a symbol placed on it.

  pin on the wire when d² < 1e-4 and 1e-6 < u < 1 − 1e-6

  Schematic wires, pins and connections addons/electrical/main.js

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  64-bit

• PV one-line layout

  Positions the symbols and wires of a solar one-line diagram from the column and row of each node.

  x = x₀ + col × pitch x; y = y₀ − row × pitch y; wire bend at (sx + ex) ÷ 2

  Schematic wires, pins and connections addons/electrical/lib/pvoneline.js

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• Transform of a schematic symbol

  The matrix that takes a symbol's pin offsets to the drawing.

  a = cos r × sx; b = sin r × sx; c = −sin r × sy; d = cos r × sy; e = x − (a bₓ + c b_y); f = y − (b bₓ + d b_y)

  Wire harness and control cabinet layout addons/harness/lib/schem.js

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  64-bit

• Squared distance from a point to a wire segment

  How far a wire end or pin is from a wire segment.

  u = clamp((p − a)·(b − a) ÷ |b − a|², 0, 1); d² = |p − (a + u (b − a))|²

  Wire harness and control cabinet layout addons/harness/lib/schem.js

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  64-bit

• Which wires and pins are connected

  Joins wire ends to other ends, to pins and to wires they touch, to find the nets.

  connected when distance² ≤ tol², tol = 0.05

  Wire harness and control cabinet layout addons/harness/lib/schem.js

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  64-bit

• A point in a rail's frame

  The distance along a rail and off its axis of a drawing point, in millimeters.

  s = (Δx cos r + Δy sin r) ÷ k; off = (−Δx sin r + Δy cos r) ÷ k

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

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  64-bit

• A rail position back in the drawing

  The drawing point at a distance along a rail.

  x = x₀ + (s cos r − off sin r) × k; y = y₀ + (s sin r + off cos r) × k

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

  • CadCraft
  64-bit

• Modules on a rail

  Which modules sit on a rail, and the stretch of rail each covers.

  s₀ = s − w ÷ 2; s₁ = s + w ÷ 2

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

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  64-bit

• Modules past the end or overlapping

  Flags a module that hangs past the rail or overlaps the next one.

  past when s₀ < −0.01 or s₁ > len + 0.01; overlap when next s₀ < s₁ − 0.01

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

  • CadCraft
  64-bit

• Free length on a rail

  The rail length not taken by modules.

  free = max(0, len − Σ module widths)

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

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  64-bit

• Where a new module sits

  The center of a new module on a rail: inside the rail, and flush to a neighbor when close.

  c = clamp(s, w ÷ 2, len − w ÷ 2); c = neighbor edge ± w ÷ 2 when within 3 mm

  Wire harness and control cabinet layout addons/harness/lib/cabinet.js

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  64-bit

• Drawing units per millimeter

  The factor between the drawing and millimeters.

  k = (1 ÷ per) × (1 ÷ 25.4 for inch rules)

  Wire harness and control cabinet layout addons/harness/main.js

  • CadCraft
  64-bit

• A harness moved, turned or scaled

  Applies a move, rotation or scale to a harness: its nodes and its scale.

  k′ = k × √(m₀² + m₁²); node′ = M · node

  Wire harness and control cabinet layout addons/harness/main.js

  • CadCraft
  64-bit

• Module positions in millimeters

  Each placed module's position for routing wires to it.

  x mm = x ÷ k; y mm = y ÷ k

  Wire harness and control cabinet layout addons/harness/main.js

  • CadCraft
  64-bit

• Total length of a harness

  The summed length of a harness's segments for the bill of materials.

  mm = Σ segment length

  Wire harness and control cabinet layout addons/harness/main.js

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  64-bit

• Wire count and bundle diameter per segment

  The number of wires in each harness segment and the diameter of their bundle, kept on the harness.

  od = round(bundleDiameter × 10) ÷ 10

  Wire harness and control cabinet layout addons/harness/main.js

  • CadCraft
  64-bit

• Rail length and angle from two points

  The length in millimeters and the angle of a rail drawn between two points.

  len = √(Δx² + Δy²) ÷ k; rot = atan2(Δy, Δx)

  Wire harness and control cabinet layout addons/harness/main.js

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  64-bit

• Modules placed in a row

  Places every remaining module along a rail, one after the other.

  center = s + w ÷ 2; s ← s + w; stop when s + w > len + 1e-9

  Wire harness and control cabinet layout addons/harness/main.js

  • CadCraft
  64-bit

• Segment length and bundle labels

  The length written beside each harness segment, and its wire count and diameter.

  mm = typed length, or √(Δx² + Δy²) ÷ k; label = round(mm)

  Wire harness and control cabinet layout addons/harness/lib/draw.js

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  64-bit

• A run moved, turned or scaled

  Applies a move, rotation, scale or mirror to a run's centerline and its scale.

  p′ = M · p; sc = √|det M|; k′ = k ÷ sc; z′ = z × sc

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

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  64-bit

• Section width in drawing units

  The drawn width of a duct section.

  width = w ÷ k

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

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  64-bit

• Branches found on mains

  Finds where a run's end sits on another run's centerline, the angle between them and how far the branch is cut back.

  sin = |t_main × t_branch|; cut = (W_main ÷ 2) ÷ sin; opening = W_branch ÷ sin; angle = round(asin(sin) × 180 ÷ π × 10) ÷ 10

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• Elbows, transitions and straight pieces

  The fittings of a run and the start and end of each straight piece along its centerline.

  T = R tan(θ ÷ 2), R = r × W; mitred: T = (W ÷ 2) tan(θ ÷ 2); elbow length = R θ or 2T; transition L = max(max(ΔW ÷ 2, ΔH) ÷ tan 15° ÷ k, minimum)

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• Length in feet or meters

  Converts a length in drawing units to feet or meters.

  feet = du × k ÷ 12; meters = du × k ÷ 1000

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

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  64-bit

• Sheet-metal area of a length of duct

  The surface area of a length of duct in square feet or square meters.

  ft² = perimeter × du × k ÷ 144; m² = perimeter × du × k ÷ 1e6

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• Elbow area and angle

  The sheet-metal area of an elbow and the angle in its name.

  area = perimeter × centerline length; name angle = round(θ × 180 ÷ π)

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• Transition area

  The sheet-metal area of a transition between two sizes.

  rectangular: bottom + top + two sides as trapezoids over their slant lengths; other: (pₐ + p_b) ÷ 2 × slant length

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• Straight pieces

  The length and area of each straight piece of a run.

  du = s₁ − s₀; length = lenOut(du); area = perimeter × du

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

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• Schedule totals

  The total duct length, total sheet-metal area and number of fittings.

  length = Σ rows; area = Σ duct areas + Σ fitting areas

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

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  64-bit

• A run in the other unit system

  Converts a run's sizes and airflows between inches with cfm and millimeters with L/s.

  size × 25.4 or ÷ 25.4; airflow × 0.47194745 or ÷ 0.47194745

  Duct runs, fittings and schedule addons/hvac/lib/duct.js

  • CadCraft
  64-bit

• A typed duct size

  Reads a size such as 24x12 or Ø14.

  Duct runs, fittings and schedule addons/hvac/main.js

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  64-bit

• A point pulled onto a run's centerline

  Moves a point picked inside a duct's outline onto its centerline, to start or end a branch there.

  inside when distance ≤ W ÷ 2 + 1e-9

  Duct runs, fittings and schedule addons/hvac/main.js

  • CadCraft
  64-bit

• Schedule table in the drawing

  The rows of the duct schedule placed in the drawing.

  shown length and area = value.toFixed(1), trailing zeros removed

  Duct runs, fittings and schedule addons/hvac/main.js

  • CadCraft
  64-bit

• Schedule CSV

  Writes the duct schedule as CSV.

  length, perimeter, area: 3 decimals; velocity: 0 decimals (inch units) or 2; friction rate: 4 decimals

  Duct runs, fittings and schedule addons/hvac/main.js

  • CadCraft
  64-bit

• Liters per second in one cfm

  The factor that converts airflow from cubic feet per minute to liters per second.

  1 cfm = 0.3048³ ÷ 60 × 1000 L/s = 0.4719474432 L/s exactly

  Duct network pressure: drawing adapter addons/hvac/lib/ductnet.js

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  64-bit

• Millimeters per drawing unit

  The factors that take a run's coordinates, sizes and airflow to millimeters and L/s.

  draw = k × 25.4 (inch) or k; size = 25.4 or 1; lps = CFM_LPS or 1

  Duct network pressure: drawing adapter addons/hvac/lib/ductnet.js

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  64-bit

• Turn at a corner

  The angle a run turns through at a corner, in degrees.

  turn = acos(u·v ÷ (|u| |v|)) × 180 ÷ π

  Duct network pressure: drawing adapter addons/hvac/lib/ductnet.js

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  64-bit

• Runs handed to the engine

  Each run's vertices in millimeters, its section size in millimeters, and its free ends with their airflow.

  vertex mm = p × draw; w mm = w × size; z mm = z × draw

  Duct network pressure: drawing adapter addons/hvac/lib/ductnet.js

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  64-bit

• Fan point matched to a run end

  Finds the run end the fan sits on and takes its height.

  nearest end by √(Δx² + Δy²); accepted when ≤ 60 mm

  Duct network pressure: drawing adapter addons/hvac/lib/ductnet.js

  • CadCraft
  64-bit