Slots Definition Plane

An OpenVPX backplane profile is a physical definition of a backplane implementation that includes details such as the number and type of slots that are implemented and the topologies used to interconnect them. Plane Kinematics of Rigid Bodies Motion Relative to Rotating Axes Relative Velocity Relations.The curved slot represents rotating x-y frame.The x-y axes are not rotating themselves.Vel of A measured relative to the plate = v rel.v rel will be tangent to the path fixed in x-y plate.Magnitude of v rel will be ds/dt.v.

A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specified datum feature. A datum is the origin from which the location or geometric characteristics of features of a part are established. During landing we want high lift and high drag, so the flaps and slats will be fully deployed. When the wheels touch down, we want to decrease the lift (to keep the plane on the ground!), so you will often see spoilers deployed on the top of the wing to kill the lift. Spoilers create additional drag to slow down the plane. Definition of slot. C: a passage through the wing of an airplane or of a missile that is located usually near the leading edge and formed between a main and an auxiliary airfoil for improving flow conditions over.

Slots Definition Plane Crashes

Electromagnetic Compatibility Consulting and Training

The most important thing that I can say about slots in ground planes,is don't have them! If you do have slots, no tracescan cross over them. If a trace does cross over the slot askyourselfthis question: Where is the return path for the current? Remember the fundamental principal of EMC, 'return currents locallyand compactly, through the smallest loop area possible.' Ifeveryonewould follow this principal, a great many of our EMC problem would goawayor at least be minimized.
Thelowest impedance signal return path is in a plane directly under thesignaltrace. Slots in ground planes divert the ground current flow(see figure), thereby producing a high ground impedance (Inductance)anda ground plane voltage drop that is the cause of increased emissionsfromthe cables connected to the board. In addition, ground planeslotswill significantly increase the crosstalk between traces thatcrossover them, and the larger loops formed by the return current paths willradiate.

Strip Plane Slot Plane

The table below shows measured values of ground plane voltage withandwithout a slot in the ground plane. The voltage measurements weremade between two point on the ground plane one inch apart and directlyunderneath the trace. The slot was cut perpendicular to thedirectionof current flow, as shown in the figure, and half way between themeasuringpoints. The entry under 'holes' represents a linear pattern offifteenholes each 0.052' in diameter (oriented perpendicular to current flow)covering a linear distance of one inch. This isrepresentativeof an array of holes for vias or thru-hole component leads. Thevoltagemeasurements were made with a 10 MHz, 3 nS rise time clock signalflowingdown the trace and returning in the ground plane. As can be seenthe array of holes did not increase the ground plane voltage, but theslotdid increase the voltage by a factor of as much as five in the case ofthe 1 1/2' slot.

Finding these problems, after-the-fact, on a buried ground planethatcannot be seen is a difficult and time consuming problem. Thereis,however, a very simple way to initially check the quality of the groundplane. When you have printed circuit boards made, ask to have oneset etched but not laminated. That way, you can look at theunlaminatedground plane and see if there are problems very quickly. It wouldbe a good practice todo this with all new designs.

Length of Slot	Ground Plane Voltage
0 inches	15 mV
1/4 inch	20 mV
1/2 inch	26 mV
1 inch	49 mV
1 1/2 inches	75 mV
Holes	15 mV

© 2001/2000 Henry W. Ott

Slots Definition Plane Games

Henry Ott Consultants48 Baker Road Livingston, NJ 07039Phone: 973-992-1793, FAX: 973-533-1442
July 16, 2002

Slots Definition Plane Game

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Definition Slot Machine

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Great Planes Slot Machine

Term Inner Boundry	Definition A worst case boundry (that is, locus) generated by the smallest feature (MMC for an internal feature and LMC for an external feature) minus the stated geometric tolerance and any additional goemetric tolerance (if applicable) from the features departure from its specified material condition.
Term Outer Boundry	Definition A worst case boundry (that is, locus) generated by the largest feature (LMC for an internal feature and MMC for an external feature) plus the stated geometric tolerance and any additional goemetric tolerance (if applicable) from the features departure from its specified material condition.
Term Datum	Definition A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specified datum feature. A datum is the origin from which the location or geometric characteristics of features of a part are established.
Term Datum Feature	Definition An actual feature of a part that is used to establish a datum.
Term True Geometric Counterpart	Definition The theoretically perfect boundry (virtual condition or actual mating envelope) or best-fit (tangent) plane of a specified datum feature.
Term Datum features subject to size variation	Definition Datum features, such as diameters and widths, differ from singular flat features in that they are subject to variations in size as well as form.
Term Datum feature simulator	Definition A surface of adequately precise form (such as a surface plate, a gage surface, or mandrel) contacting the datum feature(s) and used to establish the simulated datums.
Term Simulated datum	Definition A point, axis, ot plane established by processing or inspection equipment, such as the following simulators: surface plate, a gage surface, or mandrel.
Term Datum target	Definition A specified point, line, or area on a part used to establish a datum.
Term Dimension	Definition A numerical value expressed in appropriate units of measure and used to define the size, location, and geometric characteristis, or surface texture of a part or part feature.
Term Basic dimension	Definition A numerical value used to describe the theoretically exact size, profile, orentation, or location of a feature or a datum tatget. It is the basis from whigh permissible variations are established by tolerances on other dimensions, in notes, or in feature control frames.
Term Reference Dimension	Definition A dimension, usually without tolerance, used for information purposes only. A reference dimension is a repeat of a dimension or is derived from other values shown on the drawing or on related drawings. It is considered auxiliary information and does not govern production or inspection opertions.
Term Feature	Definition A general term appiled to a physical portion of a part, such as a surface, pin, tab, hole, or slot.
Term Axis of a feature	Definition A straight line that coincides with the axis of the true geometric counterpart of the specified feature.
Term Center plane of a feature	Definition A plane that coincides with the center plane of the true geometric counterpart of the specified feature.
Term Derived median line of a feature	Definition An imperfect line (abstract) that passes through the center points of all cross sections of the feature. These cross sections are normal to the axis of the actual mating envelope. The cross section center points are determined as per ANSI B89.3.1.
Term Derived median plane of a feature	Definition An imperfect plane (abstract) that passes through the center points of all line segments of the feature. These line segments are normal to the actual mating envelope.
Term Feature of size (FOS)	Definition One cylindrical or spherical surface, or a set of two opposed elements or opposed parallel surfaces, associated with a size dimension.
Term Individual features of size (Rule #1)	Definition Where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent to which variations in its geometric form, as well as size, are allowed
Term Maximum Material Contition (MMC)	Definition The condition in which a feature of size contains the maximum amount of material within the stated limits if size -- for example, minimum hole diameter, maximum shaft diameter.
Term Least Material Contition (LMC)	Definition The condition in which a feature of size contains the least amount of material within the stated limits if size -- for example, maximum hole diameter, minimum shaft diameter.
Term Regardless of Featue Size (RFS)	Definition The term used to indicate that a geometric tolerance or datum reference applies at any increment of size of the feature within its tolerance.
Term Resultant Contition	Definition The variable boundry generated by the collective effects of a size feature's specified MMC or LMC material condition, the geometric tolerance for that material condition, the size tolerance, and the additional geometric tolerance derived from the feature's departure from its specified material condition.
Term Virtual Condition	Definition A constant boundry generated by the collective effects of a size feature's specified MMC or LMC material condition and the geometric tolerance for that material condition.
Term Actual Size	Definition The general term for the size of a produced feature. This term includes the actual mating size and the actual local sizes.
Term Actual Local Size	Definition The value of any indiviual distance at any cross section of a feature.
Term Actual Mating Size	Definition The dimensional value of the actual mating envelope.
Term Actual Mating Envelope	Definition This term is defined according to the type of feature, as follows' a) For an external feature. A similar perfect counterpart of smallest size that can be circumscribed about the feature so that it just contacts the surface at the highest points. For example, a smallest cylinder of perfect form or two parallel planes of perfect form at minimum separation that just contact(s) the highest points of the surface(s). b) For an internal feature. A similar perfect counterpart of largest size that can be inscribed within the feature so that it just contacts the surface at the highest points. For example, a largest cylinder of perfect form or two parallel planes of perfect form at maximum separation that just contact(s) the highest points of the surface(s). For features controled by orientation or positional tolerances, the actual mating envelope is oriented relative to the appropriate datum(s), for example, perpendicular to a primary datum plane.
Term Limits of Size	Definition The specified maximum and minimum sizes.
Term Nominal Size	Definition The designation used for purposes of general identification.
Term Resultant Contition Size	Definition The actual value of a resultant contition boundry.
Term Virtual Contition Size	Definition The dimensional value of a virtual contition boundry.
Term Tangent Plane	Definition A theoretically exact plane derived from the true geometric counterpart of the specified feature surface.
Term Tolerance	Definition The total amount a specific dimension is permitted to vary. The tolerance is the difference between the maximum and minimum limits.
Term Bilateral Tolerance	Definition A tolerance in which variation is permitted in both directions from the specified dimension.
Term Geometric Tolerance	Definition The general term applied to the category of tolerances used to control form, profile, orientation, location, and runout.
Term Form Tolerance	Definition _____ tolerances control straightness, flatness, circularity, and cylindricity.
Term Flatness	Definition _______ is the condition of a surface having all elements in one plane.